Case: A 55 year old female visiting the United States from southern Mexico presents with 6 months of chronic unilateral lower extremity swelling and 2 days of erythema. What is the most common cause of this chronic disease? Click on image for a larger view.
Poll Results
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Filariasis
Explanation
This patient has chronic lymphedema with superimposed cellulitis. Lymphedema can be primary or secondary. The much more common secondary lymphedema occurs from damage to the lymphatic system by disorders as 1 :
- Chronic venous insufficiency
- Filariasis
- Malignancy
- Obesity
- Radiation therapy
- Surgery
- Trauma
Initially, lymphedema is soft and pitting. With time, subcutaneous tissue fibrosis occurs, leading to indurated skin that is difficult to compress. The pathognomonic finding, the Kaposi–Stemmer sign, is an inability to pinch a fold of skin at the base of the dorsal second toe between the examiner’s thumb and forefinger. 2 Other findings of lymphedema include:
- Cobblestone appearance
- Dependent rubor (resembling cellulitis)
- Dimpling of the skin (peau d’orange)
- Hyperpigmentation
- Nodules (representing dilated lymphatics)
- Ulceration and crusting
- Verrucous skin surface
Eventually, the leg may become massive and disfigured, a condition labeled as elephantiasis. The most common cause worldwide is filariasis. Wuchereria bancrofti, Brugia malayi, and Brugia timori are endemic to tropical areas of the world and are transmitted by a mosquito vector carrying the infected larvae. Patients actively infected with the parasite are treated with diethylcarbamazine (DEC) or doxycycline. 3
In the United States, edema most commonly occurs after axillary, pelvic or inguinal lymph node dissection for neoplastic disease. Most patients are treated conservatively with compression therapy (including compressive garments), physical therapy, or pneumatic pumps. Surgery is rare. 4