Tinea capitis

📖 About

• Very common superficial fungal infection of the scalp.
• Primarily affects children, especially in communities with overcrowding and socio-economic deprivation.

🧬 Aetiology

• Caused by dermatophytes (fungi that invade keratinised tissues).
• Most common: Trichophyton tonsurans (anthropophilic).
• Occasionally: Microsporum canis (zoophilic, spread from cats/dogs 🐱🐶).
• Transmission: direct contact or via fomites (hats, combs, bedding).

🩺 Clinical Features

• Starts as a small papule at the base of a hair follicle → spreads to form a scaly circular plaque (“ringworm”).
• Within the lesion: brittle, broken “exclamation mark” hairs ✂️.
• Confluent patches of alopecia may develop, often itchy.
• Kerion: severe inflammatory reaction → boggy, tender, granulomatous mass studded with sterile pustules.
• Systemic signs may include fever 🌡️ and regional lymphadenopathy.
• Risk of permanent scarring alopecia if untreated.

🔍 Differentials

• Alopecia areata (smooth scalp, no scaling or inflammation).
• Psoriasis or seborrhoeic dermatitis of scalp.
• Bacterial folliculitis or impetigo.
• Discoid lupus erythematosus (scarring alopecia with scaling).

🧪 Investigations

• Wood’s lamp: Microsporum species fluoresce dull green.
• KOH preparation: shows fungal spores and hyphae.
• Culture on Sabouraud medium with antibiotics confirms the species.

💊 Management

⚠️ Systemic therapy is essential – dermatophytes infect the hair shaft and follicle, so topical agents alone cannot penetrate adequately.

🧴 First-line: Oral antifungals (species-directed where possible)

• Griseofulvin (fungistatic; concentrates in keratin)
• First-line in children in many UK settings
• Particularly effective for Microsporum species
• Duration: 6–12 weeks (continue until clinical + mycological cure)
• Terbinafine (fungicidal; inhibits squalene epoxidase)
• Preferred for Trichophyton species (more common in UK)
• Shorter courses: typically 2–4 weeks (may extend if severe)
• Increasingly used as first-line due to efficacy and tolerability
• Alternatives
• Itraconazole – useful in resistant or refractory cases
• Fluconazole – option if others not tolerated

🧴 Adjunct topical therapy (important but NOT curative)

• Selenium sulfide 2.5% or ketoconazole shampoo
• Use 2–3 times weekly for first 2–4 weeks
• Reduces spore shedding → limits transmission
• Apply to scalp and leave for 5–10 minutes before rinsing

🧪 Monitoring & safety

• 🩸 LFTs if prolonged oral therapy (especially terbinafine/azole use)
• ⚠️ Check for drug interactions (notably azoles)
• Monitor adherence – long courses commonly lead to treatment failure

🚨 Kerion (inflammatory tinea capitis)

• 💥 Boggy, tender inflammatory mass with hair loss
• ⚠️ Risk of scarring alopecia if untreated
• Management:
• Oral antifungal (as above)
• 👉 Consider oral corticosteroids (short course) to reduce inflammation and scarring risk

👨‍👩‍👧 Public health & prevention

• Screen and treat household contacts (especially children)
• Use antifungal shampoo for contacts to reduce carriage
• Avoid sharing combs, hats, pillows, bedding
• Clean hair equipment and soft furnishings
• School exclusion usually not required once treatment started

🔁 Follow-up

• Clinical improvement expected within weeks, but complete cure takes longer
• Continue treatment until symptoms resolve ± negative microscopy
• Assess for treatment failure: adherence, reinfection, wrong organism

📚 References

• British Association of Dermatologists – Clinical Guidelines.
• Oxford Handbook of Clinical Dermatology.
• DermNet NZ – Tinea Capitis