A 37-year-old man comes to the office due to a rash. For the last several months, he has had numerous small lesions on the hands. The lesions are associated with occasional mild itching and bleed slightly if inadvertently struck against furniture or a wall. Examination findings are as shown in the exhibit. Which of the following is the most likely diagnosis?

Question

A 37-year-old man comes to the office due to a rash.  For the last several months, he has had numerous small lesions on the hands.  The lesions are associated with occasional mild itching and bleed slightly if inadvertently struck against furniture or a wall.  Examination findings are as shown in the exhibit.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

This patient has chronic, well-demarcated, erythematous plaques with a thick scale consistent with plaque psoriasis. Psoriasis is a common inflammatory skin disorder characterized by hyperkeratosis (overgrowth of the stratum corneum) and epidermal hyperplasia. It has a strong genetic predisposition and is often seen in patients with a family history of the disorder; other risk factors include smoking, heavy alcohol consumption, and obesity. Psoriasis has multiple variants (eg, guttate, pustular); however, up to 75% of cases are due to chronic plaque psoriasis. Plaques are well-defined and erythematous and may appear raised above the surrounding skin. They are typically covered in a coarse silver scale, which, when removed, results in pinpoint bleeding (Auspitz sign) of the underlying dilated capillaries. Plaques usually form in locations subject to trauma or friction (Köbner phenomenon); the extensor surfaces of the elbows and knees are most classic, but the dorsal surface of the hands, as in this patient, is also common. Other typical locations include the scalp, back, and gluteal cleft. They are often mildly pruritic but may be asymptomatic. (Choice A) Atopic dermatitis can present with erythematous, scaly plaques, but it is more common in flexural areas, shows less prominent scaling, and is usually associated with more prominent itching. (Choice B) Cutaneous warts (verruca vulgaris) are caused by human papillomavirus infection and present as discrete, hyperkeratotic papules. Although patients can have multiple warts, numerous scaly plaques are more consistent with psoriasis. (Choice C) Lichen planus presents with pink or purple plaques and papules. It is usually associated with severe pruritis and typically affects the volar surface of the wrists rather than the dorsum of the hands. (Choice E) Tinea manuum presents with scaly plaques on the hands. The lesions are typically very pruritic and often have an annular appearance with central clearing. Educational objective: Psoriasis is a common inflammatory skin disorder characterized by hyperkeratosis (overgrowth of the stratum corneum) and epidermal hyperplasia. Plaque psoriasis is the most common form and presents with chronic, well-demarcated, erythematous plaques with a thick, silver scale.

A 37-Year-Old Man Comes to the Office Due to a Rash