L.S. Tatibana1; D.N. Paglioni2; A.P. Costa-Val1
A one-year old female Terrier Brasileiro dog, black, white and brown coated was presented to the dermatology Service of Veterinary Hospital of Federal University of Minas Gerais with a history of permanent hair loss on the dorsal aspect of the trunk. It became evident, after physical examination that the animal was suffering from both partial alopecia on black hair areas and discreet scaling. White and brown hair areas showed integrity. Fungal culture of black hair pluckings showed negative results for dermatophytes. Microscopic examination of plucked hairs showed normal white ones in various stages of the growth phase but black hairs were mainly in telogen and showed many big melanin clumps or macromelanosomes. They were also distorted and fractured in their shafts. Skin histopathological examination permitted final diagnosis of black hair follicular dysplasia. As there is no effective treatment, it was prescribed a palliative antiseborrheic therapy. Black hair follicular dysplasia diagnosis should be dermatopathologically based: affected areas reveal accumulation of melanin clumps within hair shafts, follicular lumina, root sheaths and hair bulbs. Hair bulb melanocytes are densely pigmented, and contain abundant stage IV melanosomes but adjacent matrix keratinocytes lack melanosomes and white haired areas are unaffected. Black hair follicular dysplasia is a rare dermatological condition, that affects bi-or tricolor pure or mixed-breed dogs, and as in the case presented here, affected animals exhibit alopecia restricted solely to the black hair areas. This is the first reported case of the disease in a Terrier Brasileiro dog.