Tinea Capitis (Scalp Ringworm): Symptoms, Causes & Treatment

What Is Tinea Capitis?

Tinea capitis — commonly called scalp ringworm — is a dermatophyte fungal infection that colonises the skin of the scalp and invades the hair shafts and follicles. Despite the name, no worm is involved; the "ring" refers to the characteristic circular, scaly patches the infection can produce.

It is among the most common fungal infections of childhood worldwide, predominantly affecting children between 3 and 14 years of age, though immunocompromised adults can develop it at any age. The condition is contagious and, if untreated or treated inadequately, can cause permanent hair loss.

Causative Organisms

Tinea capitis is caused by fungi called dermatophytes — specifically genera Trichophyton and Microsporum. The dominant species varies by geography:

• Trichophyton tonsurans — the most common cause in the United States and urban areas of Western Europe; anthropophilic (human-to-human transmission), endothrix invasion pattern
• Microsporum canis — predominates in Europe, New Zealand, and parts of Asia; zoophilic (most often transmitted from cats and dogs), ectothrix invasion pattern
• Trichophyton violaceum — common in Africa and among immigrants from the Middle East and Africa
• Trichophyton schoenleinii — rare; causes the chronic scarring form called favus

How Hair Is Invaded

Dermatophytes invade the hair follicle in two patterns:

How Tinea Capitis Spreads

The infection is contagious, transmitted by:

• Direct contact with an infected person's scalp (most common)
• Shared objects — combs, brushes, hats, pillowcases, towels
• Infected animals — cats and dogs are the main source of M. canis; cattle for T. verrucosum
• Soil (rare; certain geophilic species)

Children attending schools or nurseries in crowded settings are at higher risk. Warm, humid climates increase prevalence. Contrary to common belief, poor hygiene is not a direct cause — the infection can spread in any hygienic environment through close contact.

Symptoms and Clinical Presentations

Tinea capitis presents in several distinct patterns, broadly divided into non-inflammatory and inflammatory forms.

Non-Inflammatory Forms

Gray-patch tinea capitis Circular patches of dull, grayish scaling on the scalp with hair that breaks just above the surface, leaving short stubs. Multiple patches may coalesce. Itch is variable. This pattern is typical of Microsporum species and is the classic "ringworm" appearance.

Black-dot tinea capitis Associated with endothrix infections (T. tonsurans). Hair breaks at the scalp surface, leaving black dots (remnant hair stumps) within the scaly patch. May mimic alopecia areata or seborrheic dermatitis.

Diffuse scaling Widespread fine scale resembling dandruff, sometimes without obvious alopecia. This presentation is frequently misdiagnosed and under-treated. A useful clinical clue: dandruff in a child under 12 should raise suspicion for tinea capitis.

Inflammatory Forms

Kerion A kerion is the most severe presentation — a boggy, raised, painful inflammatory mass studded with pustules and seeping serous or purulent discharge. It represents a vigorous immune response to the fungal infection rather than bacterial superinfection, though secondary bacterial colonisation can occur. Kerion risks permanent scarring alopecia if antifungal treatment is delayed.

Pustular tinea capitis Multiple follicular pustules across a broader scalp area, sometimes accompanied by enlarged lymph nodes at the back of the neck (posterior cervical lymphadenopathy) — a finding strongly suggestive of tinea capitis in a child.

Favus A rare, chronic form caused by T. schoenleinii: yellow, cup-shaped crusts called scutula form around each hair shaft, producing a honeycomb appearance and a characteristic "mousy" odor. Without treatment, extensive scarring alopecia develops.

Systemic Signs

Posterior or occipital lymphadenopathy is common, particularly with inflammatory forms. Low-grade fever may accompany severe kerion.

Diagnosis

Clinical assessment alone is insufficient — diagnosis should be confirmed, especially before committing to weeks of oral antifungal treatment in a child.

KOH Microscopy

Scalp scrapings or plucked hairs are mounted in potassium hydroxide (KOH) solution and examined under a microscope. Hyphae and arthrospores (inside or on the hair shaft depending on species) confirm dermatophyte infection. Results are available within hours and are positive in the vast majority of symptomatic cases.

Fungal Culture

The gold standard for species identification. Hair clippings or a moistened swab across the affected area is plated on Sabouraud's dextrose agar. Results take 2–4 weeks but are needed to direct antifungal selection (griseofulvin vs terbinafine), particularly where treatment has failed.

Wood's Lamp Examination

An ultraviolet light examination: Microsporum species fluoresce bright green; Trichophyton tonsurans (the most common US species) does not fluoresce, limiting this test's utility in North America.

Trichoscopy (Dermoscopy of the Scalp)

A non-invasive tool showing characteristic patterns — comma hairs, corkscrew hairs, barcode hairs, and broken hair stubs — that allow clinical diagnosis before culture results return.

Treatment

Why Topical Antifungals Fail

Topical antifungals (creams, lotions, solutions) cannot penetrate deeply enough into the hair follicle to eradicate the infection. Tinea capitis always requires systemic oral antifungal treatment for a minimum of 4 weeks, and usually 6–8 weeks or longer.

First-Line Oral Antifungals

Griseofulvin The longest-established treatment and the first-line choice for Microsporum infections:

• Children: 20–25 mg/kg/day (microsize) or 10–15 mg/kg/day (ultramicrosize)
• Adults: 500–1,000 mg/day
• Duration: 6–8 weeks (sometimes up to 12 weeks for Microsporum)
• Absorbed better with a fatty meal; take with milk or a full meal
• Availability has been inconsistent in some regions

Terbinafine Preferred for Trichophyton infections (the most common US cause); weight-based dosing in children:

• <20 kg: 62.5 mg/day
• 20–40 kg: 125 mg/day

• 40 kg: 250 mg/day

• Adults: 250 mg/day
• Duration: 4 weeks (for Trichophyton); may need 8+ weeks for Microsporum, where it is less effective

Clinical evidence supports comparable efficacy between the two agents for Trichophyton species, with a 4-week terbinafine course showing similar outcomes to an 8-week griseofulvin course.

Alternative Agents

• Itraconazole (pulse or continuous dosing): effective for both Trichophyton and Microsporum; useful when griseofulvin is unavailable or not tolerated
• Fluconazole: an alternative when first-line agents cannot be used; generally less effective than terbinafine for Trichophyton

Adjunctive Shampoo Therapy

Antifungal shampoos (2% ketoconazole, 1–2.5% selenium sulfide) do not replace systemic therapy but are strongly recommended twice weekly to:

• Reduce fungal spore shedding from the scalp (reduces household contagion)
• Speed resolution of scalp scaling
• Treat household contacts prophylactically

Managing a Kerion

A kerion is an emergency of sorts — prompt antifungal treatment is the priority. Do not incise a kerion (it is not an abscess in the usual sense; draining it spreads infection and increases scarring risk). A short course of oral corticosteroids (prednisolone) may be added alongside the antifungal to reduce inflammation and lower the risk of scarring alopecia; evidence for this is supportive though not definitive.

Contagion and School Attendance

Tinea capitis is contagious but children do not need to be excluded from school once systemic antifungal treatment has started — provided the scalp is covered and antifungal shampoo use has begun. This is the current recommendation of most pediatric dermatology guidelines.

Household contacts should be examined and treated with antifungal shampoo prophylactically, even if asymptomatic, to prevent re-infection.

Shared objects — combs, hats, pillowcases, hair accessories, headphones — should be disinfected or not shared until the infection is cleared.

Prognosis and Potential Complications

Tinea Capitis vs. Other Scalp Conditions

Tinea capitis is frequently misdiagnosed. Key differentiators:

See Ringworm vs. Dandruff on the Scalp for a detailed head-to-head comparison.