Kerion

This is a vigorous inflammatory reaction to dermatophyte infection, occasionally associated with secondary bacterial infection, that occurs on the scalp, resulting in a boggy inflammatory swelling with pustules called a kerion (1) Fever and lymphadenopathy may accompany the infection (2).

This condition is often due a zoophilic dermatophyte such as Trichophyton verrucosum from cattle. It may be also seen with anthrophilic ring worm (1).

Diagnosis is made via mycological assessment of hairs plucked from the areas of involvement together with skin scrapings

• If there is a clinical suggestion of secondary bacterial infection then swabs should also be sent for bacteriology

The prolonged use of griseofulvin (12-16 weeks) may be necessary for the resolution of this condition (1).

Incision, drainage, or debridement should be avoided (2). The crusts can be removed by soaking the Kerions with lukewarm water or saline which will have a soothing effect (1).

Without treatment kerions can lead to permanent scarring and hair loss (2).

Reference:

1. Health Protection Agency 2007. Tinea capitis in the United Kingdom:A report on its diagnosis, management and prevention
2. Fuller LC, Barton RC, Mohd Mustapa MF, et al. British Association of Dermatologists’ guidelines for the management of tinea capitis 2014. Br J Dermatol. 2014 Sep;171(3):454-63.