Acanthosis nigricans is a type of skin pigmentation disorder characterized by brown-pigmented, wartlike protuberances or elevations appearing in various body folds. There are two forms of the disease: primary and secondary. The primary form is seen exclusively in the Dachshund breed. It begins with subtle symmetrical hyperpigmentation in the armpits. The early lesions then progress slowly to hair loss. Greasy, smelly debris accumulates in more severely affected dogs. The abdomen, groin, chest, anal area, forelimbs and hock may all be involved. Secondary acanthosis nigricans refers to clinical skin reaction pattern that is characterized by visually similar lesions and is seen in a variety of breeds. Acanthosis nigricans is similar to chronic hyperplastic dermatitis, particularly due to allergy.
A careful history and physical examination is performed to identify an underlying cause. Skin scrapings are performed to rule out demodicosis, especially in young dogs. Impression smears are useful to identify bacterial and Malassezia infections. Primary acanthosis nigricans in Dachshunds is not curable. Early cases may respond to shampoo therapy and local topicalglucocorticoids, for example, betamethasone valerate ointment. As lesions progress, more aggressive systemic therapy may be useful. In secondary acanthosis nigricans, the lesions will spontaneously resolve after identification and correction of the underlying cause. However, this will not occur if secondary bacterial or yeast pyoderma are not treated appropriately. Vitamin E has been successfully used in the treatment of a variety of skin diseases including discoid and systemic lupus erythematosus, dermatomyositis, and epidermolysis bullosa simplex. Although it helps to stop itching and inflammation, vitamin E is rarely successful alone in the management of these conditions, but offers a relatively nontoxic aid to therapy.