A 41-year-old man comes to the physician with a faint skin rash over his upper body. He first noticed it in the spring season, but it worsened during the summer. The patient has mild itching, but otherwise the rash is asymptomatic. He takes omeprazole for acid reflux but his medical history is otherwise unremarkable. He does not use tobacco, alcohol, or illicit drugs. The patient has been sexually active with 2 partners during the last year, and uses condoms on most occasions. The physical examination findings are shown below.
Which of the following is the most likely diagnosis in this patient?

Question

A 41-year-old man comes to the physician with a faint skin rash over his upper body.  He first noticed it in the spring season, but it worsened during the summer.  The patient has mild itching, but otherwise the rash is asymptomatic.  He takes omeprazole for acid reflux but his medical history is otherwise unremarkable.  He does not use tobacco, alcohol, or illicit drugs.  The patient has been sexually active with 2 partners during the last year, and uses condoms on most occasions.  The physical examination findings are shown below.  
Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

Explanation: Tinea versicolor (TV) is a non-invasive fungal infection of the skin caused by Malassezia species (Malassezia furfur, Malassezia globosa, Malassezia sympodialis). Clinical findings are usually very characteristic and include multiple, often coalescing, small circular maculae that may vary in color (white, pink, or brown). The rash is typically more prominent in the summer as the organism inhibits pigment transfer to keratinocytes and makes the affected skin paler than the unaffected tanned skin. Lesions may occasionally exhibit hyperpigmentation compared to surrounding skin due to a localized mild inflammatory response. Other than cosmetic effects, TV is usually asymptomatic, although mild pruritus may be present. Typically, the lesions are located on the upper trunk, but the rash may also involve the upper arms, neck, and abdomen. TV diagnosis can be confirmed with a potassium hydroxide (KOH) preparation showing hyphae and yeast. (Choice A) Atopic dermatitis (eczema) typically affects the extremities and produces scaling and severe pruritus. Atopic dermatitis (Choice B) Pityriasis rosea is an acute inflammatory (presumed post-viral) rash characterized by an initial "herald patch" on the trunk that is followed by smaller pink/tan lesions on the trunk and proximal extremities. Pityriasis rosea (Choice C) Seborrheic dermatitis is an inflammatory disorder characterized by erythematous patches with oily scales, predominantly involving areas with many sebaceous glands (especially the face and scalp). It is also associated with Malassezia species, though the exact pathophysiology is unclear. Seborrheic dermatitis (Choice D) Secondary syphilis causes widespread mucocutaneous lesions. It has a highly variable appearance, but typical lesions are erythematous or pale pink macules that predominantly involve the flexor surfaces of the extremities as well as the palms and soles. Secondary syphilis Educational objective: Tinea versicolor is a non-invasive fungal infection of the skin characterized by multiple, often coalescing, small circular maculae that may vary in color (white, pink, or brown). It is often more apparent in the spring and summer months. Diagnosis is confirmed by potassium hydroxide preparation of skin scrapings showing yeast and hyphae. References: Superficial fungal infections. (http://www.ncbi.nlm.nih.gov/pubmed/15451228)

A 41-Year-Old Man Comes to the Physician with a Faint