A 28-year-old Caucasian woman presents to the primary care physician complaining of a painless blistering on the backs of her hands. The blisters appeared one week ago after she spent some time gardening outdoors, and are accompanied by an increased fragility of the surrounding skin. The woman states that she has never before had such symptoms, though she suspects her mother may occasionally have had a similar presentation that eventually resolved without treatment. Past medical history is significant for chronic infection with Hepatitis C virus. Current medications include oral contraceptives, which were begun last month. Physical examination also reveals mild hyperpigmentation of the face. What is the most likely diagnosis?

Question

A 28-year-old Caucasian woman presents to the primary care physician complaining of a painless blistering on the backs of her hands.  The blisters appeared one week ago after she spent some time gardening outdoors, and are accompanied by an increased fragility of the surrounding skin.  The woman states that she has never before had such symptoms, though she suspects her mother may occasionally have had a similar presentation that eventually resolved without treatment.  Past medical history is significant for chronic infection with Hepatitis C virus.  Current medications include oral contraceptives, which were begun last month.  Physical examination also reveals mild hyperpigmentation of the face.  What is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: Porphyria cutanea tarda (Choice B) is a condition that arises from the deficiency of uroporphyrinogen decarboxylase, an enzyme in the heme synthesis pathway. This condition is characterized by painless blisters, an increased fragility of the skin on the dorsal surfaces of the hands, and facial hypertrichosis and hyperpigmentation. It can be triggered by the ingestion of certain substances (e.g., ethanol, estrogens) that should be discontinued if suspect. Diagnosis is confirmed with an elevation of the urinary uroporphyrins. Phlebotomy or hydroxychloroquine may provide relief, as can interferon alpha in those patients simultaneously infected with Hepatitis C virus. Allergic contact dermatitis (Choice A) results from direct skin contact with chemicals or allergens. It is characterized by pruritus, erythema, and edema, often followed by the development of vesicles and bullae in the irritated region. Herpes zoster (Choice C) is characterized by painful vesicular lesions clustered unilaterally along the course of a nerve. The lesions are typically found on the face or trunk, and will be Tzanck smear positive. Dermatitis herpetiformis (Choice D) is characterized by pruritic papules and vesicles that appear mainly on the elbows, knees, buttocks, posterior neck, and scalp. The condition arises in the context of gluten-sensitive enteropathy, which may be subclinical. Impetigo (Choice E) is characterized by pruritic and honey-colored macules, vesicles, and bullae on the face and other exposed parts. The condition is caused by Staphylococcus aureus or group A streptococcus. Staphylococcus aureus Educational Objective: Porphyria cutanea tarda is a condition characterized by painless blisters, hypertrichosis, and hyperpigmentation. It is often associated with Hepatitis C infection and can be triggered by the ingestion of certain substances (e.g., ethanol, estrogens), which should be discontinued if suspect.

A 28-Year-Old Caucasian Woman Presents to the Primary Care Physician