Canine epidermal nevus treated with cryotherapy

Epidermal nevus is a hamartomatous disorder characterized by hyperplasia of epidermal structures in a circumscribed area of the skin. This condition has been well recognized in humans, but rarely reported in dogs. Surgical excision is the most reliable treatment, and systemic retinoids has been reported to be effective in dogs. We describe a dog with epidermal nevus treated with liquid nitrogen cryotherapy. A 5-month-old male Shetland sheepdog presented with symmetrical linear and verrucous papules and plaques with mild pruritus on the axillae, ventral trunk and perianal area. Skin lesions were noticed at 2 months of age, and the colour of lesions gradually changed from normal to brownish. The general condition of the dog was otherwise good. Complete blood counts and biochemical analysis showed no abnormalities, and skin biopsies revealed orthokeratotic hyperkeratosis and papillomatosis. Based on these findings, the dog was diagnosed with epidermal nevus and treated with liquid nitrogen cryotherapy applied with a cotton applicator stick. Five days after the treatment, the lesions began slough with mild pigmentation developing at the sites. There was no recurrence of the lesions 3 months after treatment. It appears that liquid nitrogen cryotherapy could be considered a useful therapeutic option to control this disease in dogs.