Dear Doctor, I tend to develop painful sores between my fingers and toes when I spend lengthy time in water. How do I get this condition to heal? Dinah Dear Dinah, The most common cause of painful sores in between fingers and toes, after being in water for long is fungal infection. Dampness leads to fungal infections. This manifests as itching with sores, discolored white, or reddish or brownish black patches. Scratching can lead to secondary infection causing painful swelling or angry looking red rashes. The infection may settle spontaneously and relapse again or it may be persistent. Wearing nylon socks, wearing shoes continuously for a long time can aggravate the condition. Herpes simplex infection can manifest as sores or eruptions, which may subside by itself and relapse again with multiplication of virus. At times bacterial infection may cause blisters, which are red and painful. Such infection can be secondary to denuding of skin at some point due to dryness or use of soap and water. One can develop these sores due to allergy to something present in the atmosphere or cold water itself. One can develop sores in between fingers and toes due to eczema as well. It can simply be due to excess dryness. Prevention consists in avoiding dampness. If someone has been in contact with water for a long time as during washing or swimming, the body or body parts should be wiped dry very well. Avoid use of nylons. In case of very dry skin, suitable moisturizing lotion or oil should be used at least twice a day. Diagnosis of the underlying cause of sores is easily done by looking at clinical features. Treatment consists of treating the cause. Dr Rachna Pande is a specialist in internal medicine at Ruhengeri Hospital