A 53-year-old woman arrives at the clinic with a skin rash. She has experienced a pruritic rash involving the rear thighs that has worsened during the previous three weeks. The patient just started a weight-loss exercise program and has been using a topical analgesic lotion to her thighs and buttocks after her workouts. Her medical history is ordinary, and she does not smoke, drink alcohol, or use illegal drugs. An erythematous rash with blisters, ulcers, and weeping drainage affecting the posterior thighs bilaterally, as illustrated in the figure below, is discovered on physical examination. Which of the following is the most likely finding on skin biopsy?

Question

A 53-year-old woman arrives at the clinic with a skin rash. She has experienced a pruritic rash involving the rear thighs that has worsened during the previous three weeks. The patient just started a weight-loss exercise program and has been using a topical analgesic lotion to her thighs and buttocks after her workouts. Her medical history is ordinary, and she does not smoke, drink alcohol, or use illegal drugs. An erythematous rash with blisters, ulcers, and weeping drainage affecting the posterior thighs bilaterally, as illustrated in the figure below, is discovered on physical examination.  Which of the following is the most likely finding on skin biopsy?

Quizplus · Accepted Answer

Eductional Objective: Acute allergic contact dermatitis is caused by a type IV (delayed) hypersensitivity reaction to an antigen on the skin surface.  Gross findings include erythematous, papulovesicular, weeping lesions.  Histology is characterized by spongiosis, an accumulation of edema fluid in the intercellular spaces of the epidermis.  With chronic exposure, lesions become less edematous, with thickening of the stratum spinosum and stratum corneum.

A 53-Year-Old Woman Arrives at the Clinic with a Skin