A 35-year-old man comes to the office due to skin lesions on his knees for the past several months. The lesions began as small papules and gradually increased in size but are not painful or itchy. The patient attributes the symptoms to frequent kneeling for his work as a plumber. He tried several over-the-counter emollients but has had no relief and feels embarrassed to go out wearing shorts. The patient has no other medical conditions and does not use tobacco, alcohol, or illicit drugs. Vital signs are within normal limits. Knee examination reveals bilateral findings as shown below. The remainder of the examination shows no abnormalities.
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Which of the following is the most appropriate management for this patient's skin lesions?
Plaque psoriasis | |
Skin lesions |
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Extradermal |
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Treatment |
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This patient has plaque psoriasis, a chronic skin condition characterized by well-demarcated, hyperkeratotic, erythematous plaques with a white or silver scale primarily on the extensor surfaces (eg, knees, elbows). Symptoms can be triggered by local skin trauma (Koebner phenomenon), infections, and certain medications (eg, antimalarials, indomethacin, propranolol). The diagnosis is typically made by history and physical examination, but a skin biopsy may be necessary in difficult cases.
Initial treatment for limited plaque psoriasis includes topical high-potency glucocorticoids (eg, betamethasone, fluocinonide). Vitamin D derivatives (eg, calcipotriene), topical retinoids, and calcineurin inhibitors (eg, tacrolimus) are also effective and are often chosen for the face and other areas where glucocorticoid-induced skin thinning would be problematic. Patients with moderate to severe disease (eg, >5% of total body surface area) are considered for ultraviolet phototherapy or systemic treatments, which can include methotrexate, apremilast, or biologic agents (eg, tumor necrosis factor inhibitors such as etanercept) (Choice F). Patients with psoriatic arthritis also warrant systemic treatment. However, systemic glucocorticoids are not used because glucocorticoid withdrawal can precipitate severe erythrodermic or pustular psoriasis.
(Choice A) Allergen avoidance is necessary for management of allergic contact dermatitis, which causes significant pruritus and involves exposed skin or regions that come into contact with allergenic articles of clothing (eg, leather shoes, nickel fasteners). This patient's chronic, nonpruritic lesions are more consistent with psoriasis.
(Choice B) Dermatitis herpetiformis is a dermal manifestation of gluten-sensitive enteropathy (celiac disease), and management requires a strict gluten-free diet. However, this disorder presents with intensely pruritic papules, vesicles, and bullae.
(Choice C) Hydroxychloroquine is used for systemic lupus erythematosus, which causes skin lesions predominantly in sun-exposed areas (eg, face). Hydroxychloroquine can trigger or worsen psoriasis.
(Choice D) Topical antifungals (eg, clotrimazole) are used to treat tinea corporis (ringworm). Although tinea corporis can cause scaly, erythematous patches, the lesions are typically annular, pruritic, and spread centrifugally with central clearing.
Educational objective:
Psoriasis presents with chronic, erythematous plaques with a white or silver scale, primarily located on the extensor surfaces (eg, knees, elbows). Initial treatment for limited plaque psoriasis includes topical high-potency glucocorticoids (eg, betamethasone, fluocinonide) or vitamin D derivatives (eg, calcipotriene). Patients with moderate to severe disease may require phototherapy or systemic treatment.