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Sebaceous gland dysplasia – pathology in cats

Canadas A, Sousa C, et al. Pathology in practice. J Amer Vet Med Assoc. 

June 1, 2018, Vol. 252, No. 11, Pages 1359-1361.

Frequently, case reports inform about uncommon and/or unusual cases. A recent Pathology in Practice report covered three related Persians (a sire and 2 kittens-one male and one female) that had a history of alopecia, hyperpigmentation, scales, crusts, and a general poor-quality coat. The condition had been present in the kitten since soon after birth. Treatment with broad-spectrum antimicrobials, glucocorticoids, antifungal drugs and an oral fatty acid supplement for a few months did not improve the lesions.

The female kitten was evaluated because of the dermatologic condition. The lesions included severe alopecia, scales and crusts present primarily in the area around the eyes and over the nose, and these areas were not pruritic.

Multiple skin punch biopsies were obtained and histologic examination demonstrated diffuse atrophy of sebaceous glands leading to a diagnosis of sebaceous gland dysplasia in this kitten.

This condition of sebaceous gland dysplasia is a very rare congenital dermatosis in young cats and even dogs. It is associated with abnormal sebaceous gland formation and differentiation. What is usually found clinically in these cases is a poor-quality coat and progressive hypotrichosis (less than the normal amount of hair), initially involving the head, pinnae and dorsum. Often other dermatologic conditions are suspected first such as scabies, fungal skin disease, or another congenital cutaneous skin disorder. Routine dermatologic testing methods such as microscopic examination of skin scrapings, direct examination of hairs, or fungal culture of hair follicles will easily rule out these other conditions. Evidence of nonpruritic hypotrichosis is the most striking clinical sign in these cases, usually with a noninflammatory failure of hair growth. Skin biopsies with histopathology performed are the preferred method to confirm the diagnosis in these cats.

A hereditary cause has been proposed by some due to the condition being a congenital disease affecting young animals and some littermates have identical clinical findings. Currently, the cause is unknown though other factors proposed are exposure to toxins or viruses in utero and poor-quality nutrition of the queen during pregnancy.

Total recovery from this condition should not be presumed due to the condition representing an abnormal process of sebaceous gland development and maturation. There has been description of clinical improvement with topical medication (antiseborrheic shampoos and moisturizing conditioners) or oral supplementation with omega-6and omega-3 fatty acids and Vitamin A. Additional therapy with corticosteroids or immunosuppressant therapy may be needed depending on the initial treatment response. (VLT)