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

Abstract

Two dogs presented with an asymptomatic, drip‐like configuration of alopecia 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 skin. Crusted and ulcerated lesions were occasionally present. Histopathological lesions included dyskaryosis and dyskeratosis of keratinocytes, focal basal layer vacuolation, pigmentary incontinence, and dermal mucinosis. Two different evolution stages were recognized. The condition was associated with repetitive exposure to a heat source in winter and shared similarities with Erythema ab igne in humans.