Rapid Onset of Bullous Erythema Ab Igne: A Case Report of Atypical Presentation.

Sir,

Erythema ab igne (EAI) was first described in the UK by German dermatologist Abraham Buschke in the early 1900s as a result of proximity to stoves burning with peat.[1] It is caused by repeated and prolonged exposure to infrared radiation insufficient to produce burns.[23] Heat radiation may be due to repeated body – warming techniques like the use of Kangri — an indigenous fire pot used to generate warmth during winter months- by the people of northern India,[45] frequent hot bathing, hot water bottles, heating pads, and cooking.[23] The initial manifestation of EAI is the presence of red macules at the site of exposure. These macules are most often found on the back or the lower leg parts of women. With continued episodes of heat exposure, the skin reaction evolves into a hyperpigmented reticulated macular eruption with dusky erythema, telangiectasia, and epidermal atrophy. Symptoms of burning or itching may be described by patients,[36] although bullae are rarely seen.[78] Arriving at the diagnosis of bullous EAI may be easy if it be supported by the patient's history. However, if this history is vague or if the patient denies heat injury, confirming such a diagnosis can be difficult. A combination of history, physical findings, and histology should confirm the diagnosis.[7]

In our case, a 22-year-old woman is presented with pruritic lesions over the legs since 2 weeks ago. She recalled a history of newly onset exposure to an electrical heater due to painfully cold toes. On physical examination, a bilateral reticulate hyperpigmented net-like pattern associated with tens bulla was observed on both lateral aspects of her calves. Lesions were absent over the thighs [Figure 1a and b]. The review of her systems showed only chilblains on both feet brought on by cold exposures. Laboratory findings include blood and urine testing, ESR, ANA, and SLE-specific autoantibodies; serum cryoglobulin levels, complement level was normal. Histopathological examination of her skin showed sub epidermal blisters, dermal pigmentation; vasodilation of blood vessels within the superficial dermis was seen no evidence of true vasculitis [Figure 2]. DIF was negative for IgG, IgM, and C3 deposition. We consider our case to be the bullous variant of EAI. She was successfully treated with topical 5-FU daily. Over a period of 2 months her lesions started to clear [Figure 3]. In the case of our patient skin damage initially showed itself as bullous and the main manifestation of the disease, i.e. the bilateral reticulate hyperpigmented net-like pattern revealed itself after a few days. Bullous variant of erythema ab igne should be considered a well-defined variant of erythema ab igne and kept in mind in the differential diagnosis of any Bullous lesion with unknown aetiology and should be treated and sores eliminated due to the potentially malignant condition.

Figure 1

(a) Bullous erythema ab igne- Bullae within a localized area of reticular, brown, macular pigmentation on calve (b) Reticulate erythematous patch lesion on the left calve after use of topical burrow's solution and the disappearance of bullous lesion

Figure 2

Bullous erythema ab igne. Histologic feature. Subepidermal blister and the dilated blood vessels in superficial dermis with mild perivascular lymphocytic infiltrations was seen (H and E, × 100)

Figure 3

Bullous erythema ab igne - Clearance of reticulate erythema after 2 month OF topical 5-FU