Image 20. An orang asli (aborigine) presented with this chronic non-itchy rash, of several years duration.Several individuals in his kampong had the same.The diagnosis is:

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Image 20. The classically whorled appearance of the dermatophyte Trychophyton concentricum (tinea imbricata) found commonly in SE Asia, the South Pacific, parts of Brazil etc. There may be a genetic predisposition.