Heat Source Removal Treats 89.5% of Bullous Erythema Ab Igne Cases

Removing the heat source was the treatment in 89.5% of the 19 reported cases of bullous erythema ab igne — and there is still no evidence-based guideline for the blistering variant of this heat-induced dermatosis. A review published in Archives of Dermatological Research (318(1), Article 539, DOI: 10.1007/s00403-026-05027-2) by Hanna, S. P., Jung, J. Y., and McCullough, T. pulls together every case the literature offers, and it's a short list.

The authors searched PubMed and Google Scholar using the keywords "bullous," "erythema ab igne" and "toasted skin syndrome." That search yielded 13 case reports and case series; adding one patient from their own institution brought the total to 19 patients — the entire published, English-language experience with this condition.

Erythema ab igne — the older name is toasted skin syndrome — presents as localized reticular hyperpigmentation after repeated, prolonged exposure to heat sources. The bullous variant, in which blisters appear, is rarely reported. That rarity is exactly why the review exists: to characterize how it presents, which comorbidities travel with it, and what clinicians have actually done about it.

Who gets it, and where?

The demographic and anatomical pattern was fairly consistent across the 19 patients:

• Sex: 52.6% men — a slight majority.
• Legs involved: 89.5% of patients.
• Trunk: 10.5%.
• Arms: 5.3%.

The distribution tracks the body areas most often held close to heat sources for long periods. Heat exposure was documented in 17 of 19 patients (89.5%), consistent with the established heat-induced mechanism. The review's abstracted data did not identify the specific heat sources per patient.

What does this change for work-up?

Possibly the most actionable finding: comorbidities featured prominently. Diabetes was present in 7 patients (36.8%), and hypothyroidism in 3 (15.8%). The authors suggest clinicians should consider a work-up for these systemic diseases in any patient presenting with bullous erythema ab igne — and in diabetic patients, evaluate for peripheral neuropathy.

Diagnostic practice split along recognizable lines. Seven cases (36.8%) were diagnosed clinically without tissue sampling; 12 (63.2%) were confirmed by biopsy. Most reported cases went to histopathology, but a meaningful minority relied on the clinical picture alone when it was characteristic.

Treatment: one dominant move, everything else scattered

The treatment data were dominated by a single intervention:

• Heat source removal: 89.5% of cases.
• Topical antibiotics: 26.3%.
• Topical steroids: 15.8%.

Most patients received a combination of treatments rather than a single approach, and the absence of any evidence-based guideline means current practice is drawn entirely from individual case reports — not comparative trials.

Read the percentages with care

The authors state their caveats explicitly. The case count is small. Non-English case reports were excluded. Data extraction was performed by a single reviewer, and no formal risk-of-bias assessment was carried out. With 19 patients in total, the percentages should be read as descriptive summaries of the existing literature rather than precise population estimates.

The practical takeaway for clinicians is straightforward: suspect bullous erythema ab igne in patients with blistering reticular pigmentation on heat-exposed skin, ask about heat sources, consider screening for diabetes and thyroid disease, and evaluate diabetic patients for peripheral neuropathy.

Until comparative data exist — and with 19 published cases, they may be a long way off — heat source removal plus a systemic work-up remains the evidence, such as it is.