Overview
Fungal infections of the skin, nails, and mucous membranes are extremely common. They include athlete's foot, ringworm, nail fungus (onychomycosis), and oral or vaginal thrush. They are caused by various fungal organisms that thrive in warm, moist environments.
How common is it?
Fungal skin infections affect up to 20% of people at any one time. Nail fungal infections affect about 1 in 4 adults over 60.
Causes and risk factors
Dermatophyte fungi infect skin, hair, and nails. Candida yeast causes thrush in moist areas. These organisms spread through contact with infected people, animals, soil, or contaminated surfaces.
Common risk factors
- Warm, moist environments: sweaty feet, skin folds
- Public swimming pools, showers, and changing rooms
- Walking barefoot in contaminated areas
- Immunosuppression (steroids, HIV, chemotherapy)
- Diabetes (higher risk of candida infections)
- Recent antibiotic use (disrupts normal bacterial flora)
- Nail trauma
Symptoms
- Itchy, scaly, ring-shaped rash (ringworm)
- Red, scaly, itchy skin between toes (athlete's foot)
- White patches in the mouth or throat (oral thrush)
- Vaginal itching, soreness, and white discharge (vaginal thrush)
- Thick, discoloured, crumbling nails (nail fungus)
- Skin rash in skin folds: groin, armpits, under breasts
When to see a doctor
See a doctor if rashes are not responding to over-the-counter antifungal treatment after 2 to 4 weeks, if you are immunosuppressed, or if symptoms are widespread or severe. Nail fungal infections usually need prescription treatment.
Diagnosis
Skin scraping or nail clippings sent for microscopy and culture confirm the fungus type and guide treatment. Most typical fungal rashes are diagnosed clinically.
Treatments
Topical antifungal creams
Clotrimazole, miconazole, or terbinafine cream applied twice daily for 2 to 4 weeks treats most skin fungal infections. Continue for 1 to 2 weeks after clearing to prevent relapse.
Oral antifungal medication
Terbinafine or itraconazole tablets are needed for nail infections (treatment lasting 3 to 6 months) and resistant or widespread skin infections.
Oral or intravaginal treatments for candida
Fluconazole single-dose oral capsule or clotrimazole pessary treats vaginal thrush. Recurrent thrush may need longer courses.
Self-care and lifestyle
- Keep skin dry especially between toes, in skin folds, and the groin area
- Wear flip-flops in public showers and pools
- Change socks daily and wear breathable footwear
- Treat all household members simultaneously for athlete's foot to prevent reinfection
Prevention
Good hygiene, keeping skin dry, avoiding shared footwear, and wearing flip-flops in communal areas prevent most superficial fungal infections.