MD Dermatology · 25+ yrs international practice
Dermatologist's quick take
- Fungal rashes have an 'active edge' — the border is more inflamed than the centre
- Topical steroids cause tinea incognito — fungal infection masked and spreading
- Most fungal infections respond to OTC clotrimazole or terbinafine for 2–4 weeks
- Tinea versicolor is yeast (Malassezia), not true tinea — needs different treatment
- Recurrence is the rule, not the exception — environmental measures matter as much as the cream
Across my Nairobi clinic and the international cases I review, fungal infections are probably the most-misdiagnosed dermatology presentation. The pattern I see weekly: a patient is given a strong topical steroid for 'eczema' that's actually tinea, the steroid suppresses the immune response, and the fungal infection silently expands underneath — often called tinea incognito. By the time they reach me, what should have been a 2-week clotrimazole fix has become a 6-month problem.
I'm Dr. Urhekar, and this guide will walk you through the five most common fungal infections, how to recognise each, and how to treat them properly. Throughout, I link the rest of the Ask a Dermatologist series. For visual confirmation, ScanSkinAI's free AI skin analysis is trained on tinea, candida and Malassezia.
The five common fungal infections
Ringworm (tinea corporis)
Round, scaly, expanding patch with raised border and central clearing. Body, arms, legs.
Athlete's foot (tinea pedis)
Itchy scaling between toes, often with maceration. May spread to soles (moccasin pattern).
Jock itch (tinea cruris)
Red itchy patches in the groin folds, sparing the scrotum. Common in men, athletes, hot climates.
Scalp ringworm (tinea capitis)
Scaly patches with hair loss, mostly in children. Needs oral antifungal — topical doesn't penetrate.
Tinea versicolor
Pale or pink scaly patches on chest, back, shoulders. Yeast (Malassezia), not true tinea. Doesn't itch much.
Candidiasis (intertrigo)
Bright red, glossy, sharply-bordered rash in skin folds. May have satellite pustules. Diabetes risk factor.
The 'active edge' rule
Almost every dermatophyte (true fungal) infection shows an active edge — the border of the patch is more inflamed, scaly and raised than the centre. As the infection grows outward, the centre clears. This is why ringworm is called ringworm. Eczema and psoriasis don't do this — they're diffuse and uniform.
Treatment by infection
Ringworm, jock itch, athlete's foot
Topical clotrimazole 1% or terbinafine 1% twice daily for 2–4 weeks (continue 1 week beyond visible clearance). Terbinafine is faster-acting; clotrimazole is gentler. Both are OTC.
Tinea versicolor
Ketoconazole 2% shampoo applied to wet skin, left 10 minutes, rinsed — daily for 7–10 days, then weekly for prevention. Selenium sulfide 2.5% works similarly. Note: pigment changes can take months to even out after the yeast is cleared.
Candidiasis (skin fold infection)
Nystatin or miconazole cream twice daily, plus dryness measures. In recurrent cases, screen for diabetes — sustained high blood glucose feeds candida.
Scalp ringworm and nail fungal infections
Oral antifungal (terbinafine, griseofulvin, or itraconazole) is mandatory. Topical treatment alone fails because the medication doesn't penetrate hair follicles or nail plate. Treatment runs 6 weeks for scalp, 6–12 months for toenails.
Stop fungal infections coming back
- Dry thoroughly between toes and skin folds after every shower
- Change socks twice daily during active infection
- Disinfect shoes weekly with antifungal spray; rotate pairs day-to-day
- Treat all household members simultaneously for athlete's foot/jock itch
- Avoid sharing towels, razors, or shoes
- Wear breathable fabrics (cotton, merino) over synthetic
- If sweating heavily, use absorbent powder in skin folds
When to see a doctor
- Scalp involvement with hair loss (needs oral antifungal)
- Nail discoloration, thickening, or crumbling
- Fungal infection that hasn't cleared after 4 weeks of correct OTC treatment
- You've been using a topical steroid for what you thought was eczema and it's spreading
- Diabetes or immunosuppression with any persistent skin infection
- Painful, weeping, or rapidly-expanding rash (consider bacterial superinfection)
The steroid cream warning
Never use a topical steroid on a rash you haven't confirmed is inflammatory. Steroids suppress the immune response, allowing fungal infections to expand silently — sometimes presenting as a faint, atypical rash that has lost the diagnostic active edge. If you're handed a steroid cream and the rash gets worse over a week, stop and reassess. See steroid creams: when to use, when to stop.
How ScanSkinAI helps
Use ScanSkinAI to confirm the visual pattern before you reach for a tube of steroid. Free AI skin analysis compares your photo against fungal patterns, eczema and psoriasis simultaneously.
Photo-confirm fungal vs eczema in 60 seconds
Free AI skin check identifies tinea, candida, and Malassezia presentations.
Frequently Asked Questions
Dr. Anand S. Urhekar
VerifiedMD Dermatology · 25+ yrs · Section Head, M.P. Shah Hospital Nairobi · Former UN Dermatologist
Dr. Urhekar is a board-certified dermatologist with over 25 years of practice across Africa, the Middle East and Asia. As Section Head of Dermatology at M.P. Shah Hospital Nairobi and a former UN dermatologist, he specialises in tropical skin disease, Fitzpatrick IV–VI skin care and global health.