Review Question - QID 217281

This patient who presents with asymptomatic depigmentation of her skin most likely has vitiligo. This condition is caused by autoimmune destruction of epidermal melanocytes.

Vitiligo is an autoimmune disease characterized by skin depigmentation due to the destruction of epidermal melanocytes. The disease most commonly presents between the ages of 10-30 years and can run in families, but the exact mechanism underlying the disease is unknown. Vitiligo is also associated with vitamin D deficiency, thyroid disease, and alopecia areata. Physical exam will reveal sharply demarcated lesions, and examination under Wood lamp will show fluorescent lesions. Treatment can be with corticosteroids, psoralin, and ultraviolet light.

Chen et al. review the potential mechanisms of melanocyte death in patients with vitiligo. They discuss how the production of reactive oxygen species in periods of oxidative stress contributes to epidermal melanocyte destruction.

Figure/Illustration A is a clinical photograph of a hand showing depigmented patches (yellow circles) that are classically seen in patients with vitiligo.

Incorrect Answers:
Answer 1: Hyperplasia of epidermal melanocytes is the cause of lentigo. These are hyperpigmented macules/patches that do not darken with sun exposure.

Answer 2: Infection by a cutaneous fungus is the cause of tinea versicolor, which would also present with depigmented patches that do not tan when exposed to the sun. This disease is more commonly found centrally and would be unlikely to cause confluent finger lesions. It would be diagnosed with histopathology showing a classic "spaghetti and meatballs" pattern.

Answer 4: Mutation in the tyrosinase gene is the cause of albinism. This disease would present with diffuse hypopigmentation since birth that may also be associated with ocular deficits such as nystagmus and impaired visual acuity.

Answer 5: Proliferation of epidermal keratinocytes is the cause of seborrheic keratosis, which can also present with white or pink patches; however, the lesions in this disease classically have a "stuck-on" appearance and are velvety or verrucous.

Bullet Summary:
Vitiligo is caused by the destruction of epidermal melanocytes.