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Superficial fungal infections of the skin, hair and nails
Most fungal skin infections are cured by topical treatment, but tinea capitis and onychomycosis need oral treatment — and onychomycosis is confirmed in the laboratory before starting.
Why it matters in the exam
The exam presents a child with a scaly bald patch on the scalp and occipital nodes (tinea capitis — oral treatment), an annular lesion that worsened after a steroid cream, pale patches on the back after the summer, and an adult with a thick nail asking for tablets. It asks for the right treatment and its duration.
A recurring trap is "kerion" — a swollen, pustular scalp lesion that looks like an abscess; it is an inflammatory reaction to the fungus, and it is not drained.
Superficial fungal infections are very common in primary care, so choosing correctly between a cream and a tablet, and avoiding long, costly treatment without a diagnosis, matters.
Another question deals with candida: in diabetes and obesity, moist lesions in the folds with "satellite" lesions are candida, treated with a topical azole and keeping the area dry. A recurring question is a teenager with itch and a bad smell from the foot: when tiny pits appear on the sole it is a superficial bacterial infection, not a fungus, and it is treated with a topical antibiotic and keeping the foot dry. In a child with a scaly scalp patch and enlarged neck nodes remember that treatment is always oral.
Key points
- Skin — topical treatment; scalp and nails — oral treatment.
- Tinea capitis: griseofulvin 6–8 weeks or terbinafine 2–4 weeks.
- Onychomycosis: laboratory confirmation, terbinafine 12 weeks for toenails.
- Kerion — do not drain.
- A topical steroid masks a fungal infection.
Summary table
| Condition | Presentation | Treatment | Duration and tests |
|---|---|---|---|
| Tinea capitis | Child, scaly bald patch, broken hairs, occipital nodes; kerion | Oral griseofulvin or terbinafine, and an antifungal shampoo | Griseofulvin 6–8 weeks; terbinafine 2–4 weeks |
| Tinea corporis | Annular scaly lesion with a clearer centre | Topical azole or terbinafine | 2–4 weeks; a steroid masks the lesion |
| Tinea pedis | Between the toes, itch, peeling | Topical treatment, keep dry | Bad odour with tiny pits in the sole — a bacterial infection (pitted keratolysis) |
| Onychomycosis | Thick, yellow, crumbling nail | Terbinafine 250 mg a day | 12 weeks for toenails, 6 for fingernails; laboratory confirmation and liver tests |
| Pityriasis versicolor | Pale or dark patches on the back and chest | Ketoconazole or selenium sulfide shampoo | Pale patches stay for months after cure |
| Candidal intertrigo | Moist redness with "satellite" lesions | Topical azole, keep dry | Obesity and diabetes |
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Sources
- British Association of Dermatologists, 2014 (tinea capitis) / 2022 (onychomycosis) — Guidelines for the management of tinea capitis and onychomycosis
- American Academy of Family Physicians (American Family Physician), 2021 — Common superficial fungal infections of the skin
- Goroll AH, Mulley AG. Primary Care Medicine, 8th edition (2020) — Management of superficial fungal infections
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.