PEM POCUS Series: Soft Tissue Ultrasound

PEM POCUS fascia iliaca block

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric soft tissue ultrasonography. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

Case Goals

  1. List the indications of performing a pediatric soft tissue point-of-care ultrasound (POCUS).
  2. Describe the technique for performing soft tissue POCUS.
  3. Interpret signs of cellulitis, abscess, and soft tissue foreign body on POCUS.
  4. Describe the limitations of soft tissue POCUS.
  5. Differentiate abscess from other soft tissue pathologies such as cysts and lymph nodes.

Case Introduction: Child with abdominal pain

Wendy is a 7-year-old girl who comes into the emergency department with redness, swelling, and pain on her left calf. Her symptoms started 1 week ago as a scratch which progressively got more red and painful. There has been no drainage from the lesion. She has had no fevers, but endorses elevated temperatures of 99 F.

On arrival, her vital signs are:

Vital SignFinding
Temperature100.1 F
Heart Rate95 bpm
Blood Pressure105/68
Respiratory Rate20
Oxygen Saturation (room air)100%

On her exam, you notice a 3 x 3 cm area of erythema and induration on her right calf with questionable fluctuance. The area is tender to palpation. She has no other skin findings noted, and she is able to bear weight. Given your concern for an abscess which may require drainage, a POCUS is performed.

Pediatric Soft Tissue POCUS

Figure 1. Linear ultrasound transducer


  • Use a linear, high-frequency transducer.


  • Hold the probe perpendicular to the skin.
  • Scan the area of interest in 2 orthogonal (perpendicular) planes.
  • If there is an abscess:
    • Measure the abscess in 3 dimensions.
    • Use color Doppler to ensure the structure is not vascular.

Pro Tips

  • It is often helpful to ultrasound the unaffected side as a comparison.
  • You cannot see what you didn’t scan. Scan the entirety of the affected area in 2 planes.
  • Be aware of the patient’s comfort throughout the examination.
  • A water bath may be helpful to visualize lesions in extremities such as the hands or feet.
    • The probe sits just below the water’s surface and does not need to contact the skin.
    • The benefits of using a water bath include better visualization of superficial structures and alleviates the need for direct skin contact.
waterbath technique with ultrasound image

Figure 2. Left: Water bath technique; Right: Ultrasound of a toe using a water bath (image courtesy of The Pocus Atlas and Moudi Hubeishy, MD)

soft tissue layers ultrasound

Figure 3. Normal soft tissue layers on ultrasound (image courtesy of The Pocus Atlas)

Normally on a soft tissue ultrasound, you will see layers of defined structures separated by fascial planes.

  1. Epidermis/dermis: This is the topmost layer and has an hyperechoic appearance on ultrasound.
  2. Subcutaneous tissue: This deeper layer will appear slightly more hypoechoic.
  3. Muscular layer: This even deeper layer classically appears striated in the long axis view, while in the short axis view, it will have a speckled appearance.
  4. Bone: This layer appears hyperechoic cortex with posterior shadowing.

Cellulitis has a spectrum of appearances on ultrasound. Early cellulitis may present as skin thickening (Figure 4).

pem pocus cellulitis hazy thickening

Figure 4. Cellulitis with skin thickening


As cellulitis progresses, there is effacement of the clearly differentiated structures seen above, and the tissue layers may appear hazy and hyperechoic. More advanced cellulitis may have “cobblestoning” which is the result of edematous fluid separating fat globules in the subcutaneous tissue.

pem pocus cellulitis cobblestoning

Figure 5. Cellulitis with cobblestoning


Video 1. Ultrasound showing cellulitis with cobblestoning

Abscesses can have varied appearances. They can be anechoic (black) or filled with debris leading to a heterogeneous appearance of contents. The rim may be echogenic or blend in with surrounding tissue. They may be well-circumscribed or may have irregular borders.

A. Abscess with irregular borders and heterogeneous appearance

B. Well-circumscribed abscess with heterogeneous debris

C. Larger abscess with well-circumscribed borders

D. Abscess with irregular borders and surrounding cellulitis

E. Abscess with irregular borders and more homogenous appearance

F. Superficial abscess with well-circumscribed borders

Table 1. Examples of different appearances of abscesses on ultrasound
Video 2. Ultrasound of a cutaneous abscess

Color Doppler Flow

Placing color Doppler flow on a suspected abscess is helpful to differentiate it from a lymph node or blood vessel (see “Abscess Mimickers” section for lymph node examples). It may also aid in identifying nearby vasculature.

Figure 6. Abscess with color Doppler flow

Video 3. Ultrasound of cutaneous abscess with color Doppler flow

Posterior Acoustic Enhancement

Abscesses may exhibit posterior acoustic enhancement, which results in an enhanced transmission of ultrasound waves through a fluid-filled structure. Sometimes the abscess may not be as obvious and appear less anechoic due to debris. A squish (or swirl) sign may be elicited by putting pressure on the region, which will cause movement of the abscess contents. This finding has also been called “pus-talsis”.

Figure 7. Abscess with posterior acoustic enhancement

Video 4. Ultrasound of cutaneous abscess with squish sign

Size Measurement

Abscesses should be measured in 2 planes. Measure depth in 1 plane and length in 2. An easy way to remember this is to measure a plus sign (+) in one view, and a minus sign (-) in the other.

Figure 8. Measurement of abscess in two planes (images courtesy of Dr. Munaza Rizvi)

Lymph Nodes

Lymph nodes appear as ovid and well-circumscribed structures on ultrasound and may be confused for abscesses. They may be differentiated by their homogenous echotexture, central echogenic hilum. When inflamed, they may exhibit internal vascularity which should not be seen in an abscess.

Figure 9. A lymph node with a hilum (left) and a reactive inguinal lymph node with central vascularity (right)


Cysts are fluid-filled, well-circumscribed structures which may be similar to abscesses. A common soft tissue cyst is an epidermoid cyst, which is a subepidermoid nodule filled with keratin. In addition to physical exam clues which may help distinguish cysts from abscess, cysts are typically very well-circumscribed and more homogenous in appearance.

Figure 10. Epidermoid cyst (image courtesy of The Pocus Atlas and Dr. Robert Jones)

Soft tissue foreign bodies are a common pediatric presentation and can be easily identified on ultrasound. X-rays can be used to identify foreign bodies; however, their use is limited to radiopaque objects. On ultrasound, foreign bodies often appear as a hyperechoic defect.

Figure 11. Hyperechoic foreign body (glass) embedded in the soft tissue of a foot with posterior shadowing

Video 5. Ultrasound of soft tissue foreign body

Foreign bodies embedded for a prolonged time may have signs of infection, such as cellulitis or abscess (Figure 12).

Figure 12. Wooden splinter embedded in a patient’s plantar foot with surrounding fluid collection consistent with abscess

A foreign body’s composition can affect how it appears on ultrasound. Different materials can produce characteristic ultrasound artifacts.

Foreign BodyUltrasound FindingsUltrasound Image
WoodHyperechoic with posterior shadowing
GlassHyperechoic with posterior shadowing
May have comet tail artifact

Images courtesy of Dr. Ashkon Shaahinfar

MetalVery hyperechoic
Often has a comet tail or reverberation artifact
Table 2. Foreign body characteristics on ultrasound

Foreign Body Removal

Ultrasound assistance in foreign body removal may be static (used to locate the foreign body’s position) or dynamic (using ultrasound to guide foreign body removal in real-time). Measuring the foreign body and assessing the object’s depth on ultrasound may assist in determining if bedside removal versus surgical removal is indicated.

Limited evidence suggests that there may be some sonographic differences between the papular urticaria of a “skeeter syndrome” and local cellulitis. On ultrasound, both findings will have thickening of dermal and subcutaneous tissues. Angioedema characteristically includes more linear, horizontal, striated bands — in comparison to cobblestoning found in cellulitis [1]. However, additional studies are needed to confirm this.

Figure 13. Ultrasound of angioedema (left) and cellulitis with cobblestoning (right). Angioedema image courtesy of Dr. Laura Malia.

Necrotizing fasciitis is a rare pediatric diagnosis but a rapidly progressive and life-threatening condition if not identified quickly. While necrotizing fasciitis is primarily a clinical diagnosis, imaging may be helpful when the diagnosis is uncertain. Computed tomography (CT) and magnetic resonance imaging (MRI) have good test characteristics; however, these tests are time-consuming and may not be available in all centers. CT also involves ionizing radiation. Point-of-care ultrasound has the benefit of rapid bedside use and lack of ionizing radiation.

On ultrasound, early necrotizing fasciitis presents with thickening of the subcutaneous tissue, similar to cellulitis. Fluid in the fascial layers may also be present, and a thick layer of pre-fascial fluid >4 mm has been associated with necrotizing fasciitis [2]. Subcutaneous air with dirty shadowing (Figure 14) is a characteristic but late finding in necrotizing fasciitis. These findings may be recalled using the “STAFF” mnemonic [3]:

  • Subcutaneous Thickening
  • Air
  • Fascial Fluid

Note: It may be difficult to distinguish early cases of necrotizing fasciitis from cellulitis. Therefore ultrasound should not be used to exclude necrotizing fasciitis. Patients with findings concerning for necrotizing fasciitis require additional work-up and surgical consultation.

Figure 14. Necrotizing fasciitis on POCUS exam showing the presence of air with dirty shadowing within soft tissue (image courtesy of Dr. Di Coneybeare)

For additional reading on ultrasounding necrotizing fasciitis, see these ALiEM articles:

  • As with all ultrasound applications, soft tissue POCUS is operator dependent.
  • The ultrasound can only see what is scanned. You must make sure the lesion is fully imaged.
  • It is difficult to differentiate between various types of fluid on ultrasound. For example, hematomas may resemble abscesses. Therefore clinical context is important.

There have been multiple studies (Table 3) that support the use of soft tissue POCUS for identification of cellulitis or abscess. Soft tissue POCUS has been shown to have good sensitivity and specificity. It has also been shown to be superior to clinical assessment in several pediatric studies.

POCUS can also reduce the length of stay (LOS) for our patients. In one pediatric study including 3,094 children suspected of a soft tissue infection who underwent either POCUS or radiology department ultrasound, POCUS was shown to have a shorter median LOS by 73 minutes (95% CI 52.4-93.6 min) [4].

StudyNMethodsPOCUS Sensitivity (95% CI)POCUS Specificity (95% CI)Conclusions
Gottleib et al., Ann Emerg Med 2020 [5]2,656Systematic review of adult and pediatric studies94.6%




POCUS has good diagnostic accuracy. Led to correct change in management in 10% of cases.
Lam et al., J Emerg Med 2018 [6]327Prospective cohort study of children 6mo-18yrs comparing clinical assessment to POCUS90.3%




POCUS changed management in 22.9% of cases*
Subramaniam et al., Acad Emerg Med 2016 [7]800Systematic review of adult and pediatric (patients from birth – 21yrs) studies97%




POCUS may assist physicians in distinguishing cellulitis versus abscess.
Adams et al., J Pediatr 2015 [8]151Prospective cohort study of patients 3mo-21yrs comparing clinical assessment to POCUS96%




POCUS changed management in 27% of cases.** For every 4 ultrasounds performed, 1 correct change in management.
Sivitz et al., J Emerg Med 2009 [9]50Prospective cohort study of children <18yrs comparing clinical assessment to POCUS90%




POCUS changed management in 22% of cases.
Table 3. Studies comparing soft tissue POCUS to clinical assessment in the management of soft tissue infections.
* Change in management after POCUS defined by the following:
  • Changed incision location/size
  • Added packing
  • Medical to surgical management
  • Surgical to medical management
  • Consultation of specialist
  • Other
** Change in management defined as when the ultrasound diagnosis was discordant from the physical exam and matched the ultimate lesion classification.

Case Resolution

After reviewing the literature, you decide to perform a POCUS to evaluate for skin abscess. You place a linear, high-frequency transducer over the patient’s affected area and you observe the following:

Video 6. Soft tissue ultrasound showing an abscess with heterogeneous appearance and irregular borders with posterior acoustic enhancement, surrounding soft tissue haziness, cobblestoning

ED Course

The patient underwent successful incision and drainage of the abscess, and she was discharged home with antibiotics.


Learn More…


  1. Tay ET, Ngai KM, Tsung JW, Sanders JE. Point-of-Care Ultrasound on Management of Cellulitis Versus Local Angioedema in the Pediatric Emergency Department. Pediatr Emerg Care. 2022 Feb 1;38(2):e674-e677. doi: 10.1097/PEC.0000000000002416. PMID: 34398861.
  2. Yen ZS, Wang HP, Ma HM, et al. Ultrasonographic screening of clinically-suspected necrotizing fasciitis. Acad Emerg Med. 2002;9:1448–1451. PMID 12460854.
  3. Castleberg E, Jenson N, Dinh VA. Diagnosis of necrotizing faciitis with bedside ultrasound: the STAFF Exam. West J Emerg Med. 2014 Feb;15(1):111-3. doi: 10.5811/westjem.2013.8.18303. PMID: 24578776; PMCID: PMC3935782.
  4. Lin MJ, Neuman M, Rempell R, Monuteaux M, Levy J. Point-of-Care Ultrasound is Associated With Decreased Length of Stay in Children Presenting to the Emergency Department With Soft Tissue Infection. J Emerg Med. 2018 Jan;54(1):96-101. doi: 10.1016/j.jemermed.2017.09.017. Epub 2017 Oct 27. PMID: 29110982.
  5. Gottlieb M, Avila J, Chottiner M, Peksa GD. Point-of-Care Ultrasonography for the Diagnosis of Skin and Soft Tissue Abscesses: A Systematic Review and Meta-analysis. Ann Emerg Med. 2020 Jul;76(1):67-77. doi: 10.1016/j.annemergmed.2020.01.004. Epub 2020 Feb 17. Erratum in: Ann Emerg Med. 2022 Jan;79(1):90. PMID: 32081383.
  6. Lam SHF, Sivitz A, Alade K, Doniger SJ, Tessaro MO, Rabiner JE, Arroyo A, Castillo EM, Thompson CA, Yang M, Mistry RD. Comparison of Ultrasound Guidance vs. Clinical Assessment Alone for Management of Pediatric Skin and Soft Tissue Infections. J Emerg Med. 2018 Nov;55(5):693-701. doi: 10.1016/j.jemermed.2018.07.010. Epub 2018 Aug 28. PMID: 30170835; PMCID: PMC6369916.
  7. Subramaniam S, Bober J, Chao J, Zehtabchi S. Point-of-care Ultrasound for Diagnosis of Abscess in Skin and Soft Tissue Infections. Acad Emerg Med. 2016 Nov;23(11):1298-1306. doi: 10.1111/acem.13049. Epub 2016 Nov 1. PMID: 27770490.
  8. Adams CM, Neuman MI, Levy JA. Point-of-Care Ultrasonography for the Diagnosis of Pediatric Soft Tissue Infection. J Pediatr. 2016 Feb;169:122-7.e1. doi: 10.1016/j.jpeds.2015.10.026. Epub 2015 Nov 10. PMID: 26563535.
  9. Sivitz AB, Lam SH, Ramirez-Schrempp D, Valente JH, Nagdev AD. Effect of bedside ultrasound on management of pediatric soft-tissue infection. J Emerg Med. 2010 Nov;39(5):637-43. doi: 10.1016/j.jemermed.2009.05.013. Epub 2009 Aug 8. PMID: 19665335.

Top 3 SOAR Blog Posts on Pediatric Respiratory Infectious Disease

pediatric respiratory infectious diseases soar review

There has been a well-documented growth in the use of FOAM in graduate medical education [1-4]. The decentralized nature of FOAM along with concerns with the lack of peer review make the assessment of the quality of information difficult. Several years ago, a group of physicians set out to solve these problems by modifying the traditional systematic review format, and created the Systematic Online Academic Resource (SOAR) review. The SOAR review aims to “systematically identify online resources by topic…[and] assess the quality of these resources with a validated tool, and collate links.” [5]

Our review, “Systematic online academic resource (SOAR) review: Pediatric respiratory infectious disease,” [6] is the fourth in the AEM Education and Training series – and the first focusing on pediatrics. We identified 36 high-quality blog posts on this topic.

Previous SOAR reviews included the following:

What were the top 3 posts for pediatric respiratory ID?

rMETRIQ ScoreTopicBlog/Podcast PostDate of Publication
20EpiglottitisRadiopaedia: Epiglottitis1/29/10
19Strep pharyngitisemDOCs Podcast – Episode 27: An Understated Myth? Strep Throat & Rheumatic Fever4/27/21
19Hand-foot-and-mouth diseaseRadiopaedia: Enterovirus 711/24/14

How can I find the entire list of the 36 high-quality blog posts?

Looking for a blog post on bronchiolitis? Pneumonia? Croup? Look no further! You can view these high-quality blog posts in our SOAR publication (subscription required) [6]. To make it easier, you can also identify these resources by topic on PEMBlog with Dr. Brad Sobolewski (coauthor of the SOAR review):

  1. Bronchiolitis
  2. Epiglottitis
  3. Pneumonia
  4. Croup
  5. Everything else

How did we arrive at 36 blog posts?

Using 177 search terms, our initial search yielded 44,897 resources, 441 of which met criteria for quality assessment.

  • 36 of the 441 blog posts reached the high-quality cutoff score of ≥16 using the rMETRIQ scoring tool.
  • 67 of the 441 blog posts had an rMETRIQ score of ≤7, meeting the threshold for poor quality.
  • Similar to prior SOAR reviews, there was an uneven distribution of blog posts for each topic.
  • For all of the posts reviewed, the highest mean scores were seen in the first 3 questions of the rMETRIQ tool, which relate to the “Content” domain (vs. the “Credibility” and “Review” domains).
  • Only 5 of the 441 posts specified an intended audience level.

How do our findings compare to prior SOAR Reviews?

RenalEndocrineSickle CellPediatric Resp ID
# Reviewed34175653441
High Quality34 (10%)121 (16%)8 (15%)36 (8%)
Poor Quality*NANA11 (21%)67 (15%)

* Poor quality was not assessed in the first 2 SOAR reviews

Special thanks to SOAR coauthors Brad Sobolewski, Cindy Roskind, Andrew Grock, JooYeon Jung, Shirley Bae, and Lisa Zhao.


  1. Purdy E, Thoma B, Bednarczyk J, Migneault D, Sherbino J. The use of free online educational resources by Canadian emergency medicine residents and program directors. Can J Emerg Med. 2015;17(2):101-106. doi:10.1017/cem.2014.73. PMID 25927253
  2. Mallin M, Schlein S, Doctor S, Stroud S, Dawson M, Fix M. A survey of the current utilization of asynchronous education among emergency medicine residents in the United States. Acad Med. 2014;89(4):598-601. doi:10.1097/ACM.0000000000000170. PMID 24556776
  3. Thurtle N, Banks C, Cox M, Pain T, Furyk J. Free open access medical education resource knowledge and utilisation amongst emergency medicine trainees: a survey in four countries. Afr J Emerg Med. 2016;6(1):12-17. doi:10.1016/J.AFJEM.2015.10.005. PMID 30456058
  4. Reiter DA, Lakoff DJ, Trueger NS, Shah KH. Individual interactive instruction: an innovative enhancement to resident education. Ann Emerg Med. 2013;61(1):110-113. doi:10.1016/J. ANNEMERGMED.2012.02.028. PMID 22520994
  5. Grock A, Bhalerao A, Chan TM, Thoma B, Wescott AB, Trueger NS. Systematic online academic resource (SOAR) review: renal and genitourinary. AEM Educ Train. 2019;3(4):375-386. doi:10.1002/ aet2.10351. PMID 31637355
  6. Belfer J, Roskind CG, Grock A, et al. Systematic online academic resource (SOAR) review: Pediatric respiratory infectious disease. AEM Educ Train. 2024;8(1):e10945. Published 2024 Feb 21. doi:10.1002/aet2.10945. PMID 38510728

SAEM Clinical Images Series: Not Your Usual Irritated Eye

eye irritation

In July 2022, a 32-year-old male with a past medical history of HIV (on antiretroviral therapy, CD4 390, viral load undetectable) presented to the emergency department with constitutional symptoms and a rash for 4-5 days. His symptoms included malaise, body aches, subjective fevers, a sore throat, tender, swollen neck glands, body rash, and irritation of his left eye. He also noticed fluid-filled vesicles on his face, neck, trunk, and extremities. He denied travel outside the U.S. but reported a recent trip to New Orleans. He denied any new sexual partners or known exposure to individuals with similar symptoms.

Vitals: BP 135/83; Pulse 104; Temp 100.2 °F (37.9 °C); Resp 22; SpO2 99%

Constitutional: Alert, no acute distress

HEENT: 1×1 mm raised lesion to the left medial canthus/caruncle. No appreciated LAD. Oropharynx is clear and moist, and mucous membranes are normal.

Cardiovascular: Tachycardia, regular rhythm, and normal heart sounds.

Pulmonary: Breath sounds normal, unlabored respirations.

Abdominal: Soft. Non-tender.

Skin: Numerous 5-6 mm erythematous macules, bland fluid-filled vesicles, and umbilicated lesions throughout the face, neck, trunk, and extremities.

Complete Blood Count (CBC): WBC: 19.5 10^3/mcL, Hemoglobin: 15.2 gm/dL, Hematocrit: 43.6%, Platelet count: 325 10^3/mcL

Comprehensive Metabolic Panel (CMP): Within normal limits

RPR titer: Reactive, 1:4

Syphilis antibody IgG and IgM: Positive

Orthopoxvirus DNA: Pending

HIV RNA: Pending

The patient has Monkeypox with involvement of the caruncle of the left eye. The patient tested positive for non-variola orthopoxvirus DNA. Ophthalmology was consulted and did not find any other signs of compromise to the eye and recommended treatment with artificial tears. The patient received 14 days of Tpoxx. The patient’s eye lesion and symptoms resolved and he was discharged on hospital day eight.

Ocular lesions are a rare presentation of the monkeypox virus. There is limited literature documenting eye involvement and pictographic examples of its presentation. During the current outbreak, ocular involvement has been used as a criteria for hospital admission. The most commonly seen ophthalmologic lesions include a vesicular rash of the orbital and periorbital skin (25%), focal conjunctiva lesions, blepharitis, and conjunctivitis. Rarely, lesions can process to corneal ulcerations, keratitis, and vision loss. Given the late risk of vision loss in cases of ocular manifestations, clinicians should be aware of the varied presentation of ocular lesions associated with the monkeypox virus.

Take-Home Points

  • While rare, ocular involvement of Monkeypox is associated with vision loss, and should be promptly identified and addressed by a clinician.
  • If there is ocular involvement of primarily cutaneous pathology, a thorough eye exam is indicated in the initial assessment of the patient.
  • Abdelaal A, Serhan HA, Mahmoud MA, Rodriguez-Morales AJ, Sah R. Ophthalmic manifestations of monkeypox virus. Eye (Lond). 2023 Feb;37(3):383-385. doi: 10.1038/s41433-022-02195-z. Epub 2022 Jul 27. PMID: 35896700; PMCID: PMC9905463.
  • Kumar N, Acharya A, Gendelman HE, Byrareddy SN. The 2022 outbreak and the pathobiology of the monkeypox virus. J Autoimmun. 2022 Jul;131:102855. doi: 10.1016/j.jaut.2022.102855. Epub 2022 Jun 25. PMID: 35760647; PMCID: PMC9534147.
  • Thornhill, John P., et al. “Monkeypox virus infection in humans across 16 countries—April–June 2022.” N Engl J Med. 2022 Aug 25;387(8):679-691. doi: 10.1056/NEJMoa2207323. Epub 2022 Jul 21. PMID: 35866746.

SAEM Clinical Images Series: Fever with Rash


A 40-year-old male, tailor by occupation, was brought to the Emergency Department with complaints of high-grade fever for the past 11 days. Fever was documented to be 102°F and was not associated with any chills or rigors. The patient also complained of shortness of breath for one week associated with a dry cough, as well as an altered sensorium for one day. The patient during his hospital stay developed ARDS and was on mechanical ventilation for 20 days. He was then extubated and discharged after 27 days.

Skin: Multiple eschars on knee, foot, and lower chest.

Complete Blood Count: WBC 31,000; Plt 12,000

BUN: 215 mmol/L

Creatinine: 2.5 mmol/L

Liver Function Tests: AST 192 IU/L; ALP 591 IU/L

Blood PCR for Scrub Typhus was found to be positive.

Scrub typhus is often diagnosed clinically based on exposure to endemic regions and its characteristic eschar, which usually appears on the lower extremities, axillae, or genital region. [1,2] Still, diagnosis can be tricky, and similar eschars can be caused by spider bites, Mediterranean spotted fever, Queensland tick typhus, African tick-bite fever, and anthrax. [3] Scrub typhus is a potentially fatal mite-borne rickettsial infection caused by Orientia tsutsugamushi. It is endemic to the Asia–Pacific region, which has an estimated 1 million instances per year. Those affected may have headaches, myalgias, hearing loss, and rash, in addition to fever. Encephalitis, hepatitis, and pulmonary and cardiac involvement can occur. [1,2]

Early empiric treatment with Doxycycline is life-saving.

Take-Home Points

  • Consider Scrub Typhus in a patient presenting with eschars.
  • Early empiric treatment with Doxycycline is life-saving.
  • Botelho-Nevers E, Raoult D. Fever of unknown origin due to rickettsioses. Infect Dis Clin North Am. 2007 Dec;21(4):997-1011, ix. doi: 10.1016/j.idc.2007.08.002. PMID: 18061086.
  • Hendershot EF, Sexton DJ. Scrub typhus and rickettsial diseases in international travelers: a review. Curr Infect Dis Rep. 2009 Jan;11(1):66-72. doi: 10.1007/s11908-009-0010-x. PMID: 19094827.
  • Shiao CC, Lin SY. Eschar: a clue to scrub typhus. CMAJ. 2011 Oct 18;183(15):E1152. doi: 10.1503/cmaj.101929. Epub 2011 Sep 12. PMID: 21911554; PMCID: PMC3193135.

SAEM Clinical Images Series: Face and Chest Rash

chicken pox

A 23-year-old female with a past medical history of asthma presented with a rash that began five days ago on her face and spread to her chest. The lesions are painful and pruritic, spreading slightly to her extremities. She noted a slight sore throat and nasal congestion. She denied any known fever and had no known vaginal or oral lesions. She has a 5-year-old daughter at home with no known symptoms. She is sexually active with one male partner who has no rash or illness. She is vaccinated for COVID-19. She is unsure of childhood illnesses and believes she was never properly immunized as a child in Central America.

Vitals: BP 110/55; Temperature 37°C; pulse ox 97%

Skin: Face, thorax, and extremity papules are noted with an erythematous base, some vesicular, others with occasional crust or scabs. No dermatomal distribution. There is relative sparing of extremities with more lesions noted on the trunk and face. Negative Nikolsky sign. Otherwise, no other findings on physical examination.


Herpes varicella-zoster, or chickenpox, is a viral infection transmitted by airborne droplets and direct contact. Before immunization, 90% of cases occurred in children. While primary infection in children is generally benign, adult and infant infections can have severe complications including encephalitis and pneumonia. Erythematous vesicular lesions appear in successive crops typically starting on the face and spreading to the trunk. Extremities usually have more minor involvement with sparing of palms and soles. Vesicles progress quickly to crusted erosions in 8-to-12-hour periods. Treatment should focus on symptomatic care.

Antivirals can slow the severity of the course if given within 24 hours of the onset. Severely immunocompromised patients should receive acyclovir 10 mg/kg IV every 8 hours for 7 to 10 days.

Take-Home Points

  • Chickenpox presents with several “crops” of lesions: papules, vesicles, and scabs.
  • Adult primary disease is not common and is more severe than pediatric illness.
  • Antivirals are not indicated after the first day of illness in immunocompetent adults with mild to moderate disease.

  • Gomez-Gutierrez AK, Flores-Camargo AA, Casillas Fikentscher A, et al. Primary varicella or herpes zoster? An educational case report from the primary care clinic. Cureus Apr 2022;14(4):e23732.
  • Hughes CM, Liu L, Davidson WB, et al. A Tale of Two Viruses: Coinfections of Monkeypox and Varicella Zoster Virus in the Democratic Republic of Congo. Am J Trop Med Hyg. 2020 Dec 7;104(2):604-611. doi: 10.4269/ajtmh.20-0589. PMID: 33289470
  • Kennedy PGE, Gershon AA. Clinical Features of Varicella-Zoster Virus Infection. Viruses. 2018 Nov 2;10(11):609. doi: 10.3390/v10110609. PMID: 30400213
  • Wolff K, Johnson RA Saavedra AP. Fitzpatrick’s Color Atlas of Clinical Dermatology. 7th ed. McGraw Hill. 2013:673-675.

SAEM Clinical Images Series: A Serious Pain in the Neck


An otherwise healthy 34-year-old male presented to the Emergency Department with two weeks of anterior neck pain. Symptoms began with several days of pain in his mandibular molars, progressing to pain and swelling in the neck. In the last several days, the patient developed warmth and redness in the chest wall associated with subjective fever and chills. Additionally, the patient reports difficulty swallowing solid foods secondary to odynophagia associated with intermittent globus sensation. He has no history of immunocompromise and denies any drug or alcohol use. Of note, he has not seen a dentist in many years.

Vitals: BP 115/80; HR 120; T 101°F; RR 16; O2 sat 97%

General: Well appearing in no acute distress

HEENT: Poor dentition, mild trismus. No gingival inflammation or swelling or induration to suggest abscess. The floor of the mouth is unremarkable.

Skin: The neck and upper chest demonstrate erythema and tenderness with an enlarged area of fluctuance on the superior aspect of the left breast (Figure 1).

White blood cell (WBC) count: 6.3 k/uL

Lactate: 1.6 mmol/L

Glucose: 95 mg/dL

Creatinine: 0.72 mg/dL

Lemierre Syndrome, also known as septic thrombophlebitis of the internal jugular vein, is a rare condition with an incidence of 3-15 cases per million people. This condition occurs when an oropharyngeal or odontogenic infection spreads locally from pharyngeal tissue to the internal jugular vein. The pathogens classically arise from normal oral flora, most commonly Fusobacterium necrophorum. The presentation may be associated with trismus and/or dysphagia. Subsequent complications, including localized abscess formation and bacteremia, stem from a combination of surrounding tissue invasion and systemic septic embolization.

Given the potential for regional lymphatic spread and septic embolization, patients may present with both local and systemic findings. Skin exam may reveal regionalized cellulitic or infectious changes overlying the neck or chest (Figure 1).

Respiratory signs and symptoms may suggest the presence of pulmonary septic emboli or mediastinitis.

Constitutional symptoms including fever, chills, and fatigue are common though nonspecific. The differential is broad and includes a number of infectious, lymphatic, endocrine, and neoplastic conditions.

It is essential for the clinician to consider the alternative diagnosis of Ludwig’s Angina through careful evaluation of the oral floor.

Given the potential for oropharyngeal and respiratory compromise, emergency clinicians must maintain a high index of suspicion for this condition. Diagnostics should include laboratory studies with blood cultures, as well as CT imaging of the neck and chest to evaluate for filling defects of the internal jugular vein.

When entertaining the diagnosis, early antibiosis is prudent. Treatment should include both an extended course of antibiotic therapy as well as surgical source control of abscesses. Given the propensity for thrombus development (Figure 2), anticoagulation may be considered, but its indication here remains controversial. Patients with Lemierre Syndrome will require surgical consultation and hospital admission.

Take-Home Points

  • Lemierre Syndrome is a septic thrombophlebitis of the internal jugular vein most commonly occurring via direct spread from the oral cavity. Distinction from Ludwig’s Angina is imperative.
  • Given the proximity to critical structures and the potential for systemic organ dysfunction from septic emboli, emergency physicians need to maintain a high clinical suspicion for this rare diagnosis.
  • Treatment includes parenteral antibiotics and prompt consultation of medical and surgical subspecialists to identify the infectious source as well as mitigate against systemic spread and/or thrombus propagation.
  • Kuppalli K, Livorsi D, Talati NJ, Osborn M. Lemierre’s syndrome due to Fusobacterium necrophorum. Lancet Infect Dis. 2012 Oct;12(10):808-15. doi: 10.1016/S1473-3099(12)70089-0. Epub 2012 May 25. PMID: 22633566.

SAEM Clinical Images Series: A Painful Swollen Digit


A 50-year-old male with a history of polysubstance use disorder and poorly-controlled type 2 diabetes mellitus presents with left hand pain. One week ago, the patient sustained a macerating injury of the left distal middle digit. Since that time he has experienced worsening pain throughout the digit, now associated with diffuse swelling and discoloration. The patient also reports reduction in range of motion.

Vitals: Temp 97.6°F (36.4°C); BP 134/89; HR 87; Resp 16

General: Uncomfortable appearing male.

Musculoskeletal: Left hand third digit with fusiform edema, diffuse erythema, and warmth. Held in passive flexion at rest. Skin breakdown noted at distal fingertip with scant serous drainage. Tender to palpation, most markedly over the volar surface of the PIP joint. Patient reports severe pain with passive extension at the MCP, PIP, and DIP joints.

Glucose: 296

White Blood Cell (WBC) Count: 8,000/μl

ESR: 54 mm/hr

Infectious flexor tenosynovitis is an infection of the flexor tendon and synovial sheath with a significant risk of complications (e.g., tendon rupture, loss of function, amputation) if not promptly treated. Patients classically present 2-4 days after penetrating trauma to the hand (e.g., bite/scratch, puncture wound, laceration, injection).

This diagnosis is suggested clinically by four cardinal findings, the Kanavel signs:

1) diffuse “fusiform” swelling of the digit (most common)

2) digit held in passive flexion

3) tenderness to percussion over the flexor sheath

4) pain with passive extension

Although fundamentally a clinical diagnosis, the initial evaluation for infectious flexor tenosynovitis should include laboratory studies including complete blood count (CBC) and inflammatory markers (ESR/CRP). Radiographs may be performed to evaluate for occult traumatic injury or foreign body. Treatment includes emergent consultation of orthopedics or hand surgery, initiation of intravenous (IV) antibiotics, and hospital admission. Antibiotics should target gram-positive organisms (Staphylococcus, including MRSA, and Streptococcus). In immunocompromised patients, additional coverage against gram-negative organisms and anaerobes may be needed. Risk factors for poor outcomes include immunocompromise (HIV, diabetes, immunosuppression), intravenous drug use, peripheral vascular disease, and polymicrobial infection.

Take-Home Points

  • Infectious flexor tenosynovitis is a surgical emergency that is diagnosed clinically by the presence of one or more of the four Kanavel signs on physical exam.
  • History of trauma or penetrating injury and immunocompromised status should raise suspicion for infectious flexor tenosynovitis; common pathogens include Staphylococcus and Streptococcus species.
  • Treatment includes emergent consultation with orthopedics or hand surgery as well as early initiation of IV antibiotics.

  • Ritter K, Fitch R. Tenosynovitis. In: Knoop KJ, Stack LB, Storrow AB, Thurman R. eds. The Atlas of Emergency Medicine, 5e. McGraw Hill; 2021. Accessed November 30, 2022.
  • Hyatt MT, Bagg MR. Flexor Tenosynovitis. OrthopClin N Am 2017;48:217-27.
  • Pang HN, Teoh LC, Yam AKT, Lee JYL, Puhaindran ME, Tan ABH. Factors affecting the prognosis of pyogenic flexor tenosynovitis. Journal of Bone and Joint Surgery. 2007;89(8):1742-1748.

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