Chronic radiant heat dermatitis (Erythema ab igne) in two dogs

Two dogs presented with an asymptomatic. drip-like configuration of alopeci a over the dorsolateral thoracic reion. The exposed skin showed erythema or hypopigmentation bordered by hyperpigmentation. The skin changes extended into the pelage with a sharp demarcation between affected and unaffected sk in. Crusted and ulcerated lesions were occasionally present. Histopathologi cal lesions included dyskaryosis and dyskeratosis of keratinocytes, focal b asal layer vacuolation, pigmentary incontinence, and dermal mucinosis. Two different evolution stages were recognized. The condition was associated wi th repetitive exposure to a heal source in winter and shared similarities w ith Erythema ab igne in humans.