Mycosis

The skin normally hosts a varied microbial flora that includes microscopic fungi. When the skin barrier is disrupted, when local humidity rises or when immune defences weaken, these fungi can multiply in the horny layer, in the nails or in the hair shaft and produce an infection known as mycosis. The fungi feed on keratin, the protein that makes up the outer layer of the skin, the nails and the hair, and their presence triggers a local inflammatory reaction: redness, scaling and itching.

Who can develop a mycosis. Cutaneous mycoses occur at any age and in both sexes. They are more common in people who sweat heavily, in athletes, in those who wear closed footwear for many hours a day, and in people with diabetes, obesity, reduced immunity, or who are on prolonged courses of antibiotics or corticosteroids. Scalp mycosis is seen mainly in children, while nail mycosis becomes more frequent with advancing age.

Forms of cutaneous mycosis. Classification follows the fungus involved and the area affected:

• Tinea corporis — a dermatophyte infection of glabrous skin, with round or oval plaques bordered by an active, slightly raised and scaly edge that spreads in a ring while the centre clears.
• Tinea pedis — “athletes foot”, located between the toes and on the sole, with fissures, scaling, maceration and an unpleasant odour.
• Tinea cruris — affects the groin folds and inner thighs, with itchy red-brown plaques and a sharply defined border.
• Tinea capitis — scalp mycosis, with scaly areas and hairs broken off short, sometimes with intense inflammation.
• Onychomycosis — nail infection, with thickening, opacity, yellowish discolouration and crumbling of the nail plate.
• Mucocutaneous candidiasis — caused by yeasts of the genus Candida, appearing in skin folds, at the corners of the mouth, under the breasts, in the nappy area or on mucous membranes, with intense, moist redness and a fine scaly border.
• Pityriasis versicolor — caused by yeasts of the genus Malassezia, with small, faintly scaly patches lighter or darker than the surrounding skin, on the trunk, shoulders and neck.

Causes and risk factors. The fungi involved are transmitted from person to person, from animals or from the environment — soil, changing rooms, swimming pools, saunas. The risk increases with:

• prolonged local heat and humidity, heavy sweating;
• tight synthetic footwear and clothing that prevents evaporation;
• sharing towels, slippers, combs or razors;
• small injuries to the skin and nails, circulatory problems in the legs;
• diabetes, obesity, immunosuppression, prolonged treatment with antibiotics, corticosteroids or immunosuppressants;
• contact with pets or farm animals that carry the fungus.

What the patient notices and how it evolves. The onset is usually discreet: a slightly scaly reddish patch, intermittent itching between the toes, or a small change in the colour of a nail. Left untreated, the lesions spread slowly, may merge and may become secondarily infected by bacteria. Mycoses tend to recur, particularly when the predisposing factors persist. Nail forms evolve most slowly and demand the greatest patience, since regrowth of the nail plate takes many months.

What makes mycoses worse. Applying corticosteroid creams without a correct diagnosis masks the inflammation and alters the appearance of the lesion, making it harder to recognise. Other aggravating factors are scratching, excessive washing with harsh products, insufficient drying of skin folds and toe spaces, stopping treatment too early, and reusing contaminated footwear.

At our practice, mycosis is approached through the Kozak Method — internal and external treatment, individualised, based on consultation. Results differ from one patient to another.