Common Skin Infections

Infections caused by Corynebacterium

Corynebacterium (the bug also responsible for Diphtheria) can cause 2 rashes:

Erythrasma 

Presents as an orangy-brown flexural rash often seen in the axillae or toe web spaces. It is frequently misdiagnosed as a fungal infection but the very distinct colour is usually helpful in making the diagnosis. The rash shows a dramatic coral pink fluorescence under Wood's (ultraviolet) light. It is caused by Corynebacterium minutissimum and is easily treated with Erythromycin either orally or I often use the topical form which is licensed for use in acne. -oral Erythromycin (500mg four times daily for 10 days).

Erythrasma – orangy-brown rash in groin Fluoresces pink under Wood’s light

Pitted keratolysis

This is a superficial infection of the horny layer of the skin frequently involves the soles of the forefoot and appears as numerous small punched-out circular lesions of a rather macerated skin (e.g. as seen after prolonged immersion). There is usually an associated hyperhidrosis of the feet and a prominent odour. It can be confused with mosaic warts but when you look carefully you will see that there are pits rather than black dots (which are seen in warts).

Treatment: topical antibiotics (e.g. fusidic acid, clindamycin or erythromycin; apply twice daily for 2-4 weeks) and topical anti-sweating lotions.

 Pitted keratolysis - clustered white punched-out pits