History of present illness: A 46 year-old female with a past history of fibromyalgia, irritable bowel disease, and chronic abdominal pain presented to the emergency department with abdominal pain, nausea, and vomiting. She reported a one-year history of similar symptoms but states that her symptoms are worse today than usual, and not improved by her home hydrocodone, medical marijuana, or heating pad use – all of which she uses daily. She has not been able to tolerate oral intake today, vomiting up her breakfast of plain toast.
The patient was observed using her home heating pad in the emergency department.
General Appearance: A chronically ill-appearing adult female who smelled of marijuana
Abdominal Exam: No focal tenderness and a non-pruritic reticulated rash
WBC: 10.6 × 109/L
AST: 21 U/L
ALT: 19 U/L
Lipase: 26 U/L
Urine analysis: Non-infected
Erythema ab igne
This rash is also known as “hot water bottle rash” or “toasted skin syndrome.” It results from chronic exposure to low levels of heat or infrared radiation. In our patient’s case, she experienced this rash stemming from her daily heating pad use (i.e. the “toast” in ‘Tea & Toast’, while the tea is old-school slang for the patient’s daily marijuana use).
Other cases have been seen in patients with occupational exposures (such as metal workers) or people who are using their laptop computers on their laps .
The treatment involves removal of offending heat source, but may require additional medical treatment if cosmetic lesions persist.
Take Home Points
- Erythema ab igne is a benign but dramatic appearing rash that is seen with chronic exposure to a low-level heat source.
- The mainstay of treatment involves removal of the heat source.
- Most rashes will fade on their own over time, but may require referral to a dermatologist for cosmetic treatment, if symptoms persist.
- Miller K, Hunt R, Chu J, Meehan S, Stein J. Erythema ab igne. Dermatol Online J. 2011 Oct 15;17(10):28. PMID: 22031654.