Tinea nigra is a rare skin infection that most commonly appears in the feet and hands in the form of patches of darkened skin. This condition is the result of a fungal infection of the skin and is treatable with anti-fungal ointments. It tends to be most common in tropical regions. Patients who notice skin changes should see a dermatologist for evaluation, as they can be a sign of a number of medical issues. If they have a recent history of travel, this information can be important to bring up, as some skin infections are limited to specific geographic areas and may not be considered as a diagnosis unless the doctor knows about the travel.
In cases of tinea nigra, a mold spreads below the surface of the skin, creating a scaly lesion that may be brown to black in color. Several species can cause this infection, which tends to favor the palmar and plantar aspect of the hands and feet. The lesions should not itch and are not painful, but may be unsightly. They can also spread if not treated, as the fungus will gain a foothold.
This condition tends to be particularly common in people who sweat heavily, as the mold thrives on moisture. The damp heat of closed shoes can be particularly pleasant for the fungus, which may bloom quickly across the feet in tropical regions during warm weather. Athletes and people who engage in heavy physical labor may notice an increased incidence of tinea nigra because of the increased heat and sweat around their hands and feet.
Treatment involves regular applications of topical cream, ideally applied after gently washing the area and patting it dry. It may also be necessary to purchase new shoes or shoe liners, or to clean shoes thoroughly before re-use. Patients who experience the condition because of hyperhidrosis may also want to consider treatment for their excessive sweating, as it can increase the risks of a recurrence. People can also limit the chances of a repeat incident of tinea nigra by avoiding bare soil, as this is where the mold prefers to live.
Fungal infections of the hands and feet are sometimes persistent and hard to treat. If a case of tinea nigra does not initially respond to treatment, the patient may need to try a different medication. The doctor may consider a culture to determine the specific organism responsible, as the medication may not be effective against that particular species.