Review Question - QID 104213

Tinea corporis is a pruritic, annular scaly erythematous rash with central clearing and raised borders that is diagnosed by visualization of hyphae when potassium hydroxide (KOH) is added to skin scrapings.

Tinea corporis is a dermatophysis, or superficial fungal infection of the skin, colloquially known as ringworm. If present on the scalp it is known as tinea capitus; the feet, tinea pedis; in the groin, tinea cruris. It is transmitted by close contact in warm, moist, environments (locker rooms, pools, towels). Wrestlers are at particular risk if mat surfaces are not properly disinfected. Treatment is by topical antifungal including terbinafine, itraconazole, and fluconazole. Griseofulvin is falling out of favor due to required duration of treatment, reoccurrence rate, and its bitter taste.

Hsu et al. review the differential for annular skin lesions and note that though many dermatophyses can be easily identified, some other common or worrisome causes of annular skin lesions include pityriasis rosea, tinea versicolor, Hansen's disease (leprosy), sarcoidosis, urticaria, erythema multiforme, and Lyme disease.

Adams examined high school wrestling and indoor track teams during a normal season in order to determine point prevalence of tinea corporis gladiatorum (i.e. not during an outbreak). He found that 7/29 wrestlers (24%), but no members of the track team had clinical lesions of tinea corporis (p=0.005), and suggested that teams be vigilant about examining and treating their athletes prior to practice and competition.

Illustration A shows typical rash of tinea corporis.
Illustration B shows lesions of Hansen's disease.
Illustration C shows pityrasis rosea.
Illustration D shows erythema multiforme.
Illustration E shows erythema migrans rash of Lyme disease.

Incorrect Answers:
Answer 1: Acid-fast bacilli on skin scraping, along with loss of sensation in patches and thickening of peripheral nerves are diagnostic criteria for Hansen's disease (leprosy).
Answer 2: A herald patch (a solitary lesion appearing 1-2 weeks before multiple lesions erupt) is characteristic of pityrasis rosea.
Answer 4: Symmetrical bilateral distribution on extremities progressing proximally is characteristic of erythema multiforme, an idiopathic rash that often follows infection or drug exposure.
Answer 5: Presence of erythema migrans (a target-shaped rash) is sufficient to make the diagnosis of Lyme disease in an endemic region.