Author: Dr Anthony Yung, Waikato Hospital, Hamilton, New Zealand, 2008.
What is keratosis circumscripta?
Keratosis circumscripta is a rare, harmless skin condition. The original cases were 11 African patients descended from the Yoruba tribe of Nigeria. Some authorities do not recognise keratosis circumscripta as a separate and distinct skin condition.
The cause of keratosis circumscripta is unknown.
Keratosis circumscripta occurs in children, usually appearing and developing over 2-3 weeks. It is characterised by circular patches consisting of aggregations of small skin colour papules (bumps) with a small plug of rough keratin protruding from the tip of the papule.
Keratosis circumscripta typically affects the elbows and knees, and very occasionally, the backs of the hands and feet, trunk, neck, base of the spine, shoulders and hips.
Treatment of keratosis circumscripta is difficult as it usually fails to improve whatever is tried. Exfoliating agents containing urea, salicylic acid or alpha hydroxyacids may help remove the rough keratin plugs temporarily.
Keratosis circumscripta tends to increase in size over a few years and may persist long term.
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