A 25-Year-Old Man With Itchy Lesions: Osmosis USMLE Study Question

November 15, 2019

Answer: B. Betamethasone, topical

This patient most likely has plaque psoriasis, an immune-mediated disease caused by hyperproliferation of keratinocytes in the epidermis and inflammatory cell infiltrates. There are 5 main types of psoriasis: plaque, guttate, inverse, pustular, and erythrodermic. Plaque psoriasis, also known as psoriasis vulgaris, makes up about 90% of cases. It typically presents with red patches with white scales on top. Areas of the body most commonly affected are the back of the forearms, shins, around the navel, and the scalp.

Guttate psoriasis has drop-shaped lesions. Pustular psoriasis presents with small non-infectious pus-filled blisters. Inverse psoriasis forms red patches in skin folds. Erythrodermic psoriasis occurs when the rash becomes very widespread and can develop from any of the other types. Fingernails and toenails are affected in most people at some point in time. This may include pits in the nails or changes in nail color.

The mainstays of treatment for psoriasis are anti-inflammatory and immunomodulatory therapies (eg, topical steroids, topical calcineurin inhibitors, anti-TNF-alpha agents). Betamethasone is a moderately potent corticosteroid that can be administered topically for the treatment of plaque psoriasis.

Major takeaway: Plaque psoriasis is characterized by raised areas of inflamed skin covered with silvery-white scale. Treatment for psoriasis includes topical steroids, such as betamethasone.

Read more about psoriasis.


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