Tinea Capitis

Dermatophyte fungal infection of the scalp hair follicles and surrounding skin

Aetiology

Caused by dermatophytes, mainly:
  • Trichophyton tonsurans (most common worldwide)
  • Trichophyton violaceum
  • Microsporum canis
  • Microsporum audouinii

Patterns of Hair Invasion

  • Endothrix: fungal spores inside hair shaft (Trichophyton)
  • Ectothrix: spores on hair surface (Microsporum)

Epidemiology

  • Most common in children aged 3–7 years
  • Rare after puberty (protective effect of sebum)
  • Higher prevalence in crowded living conditions, bad hygiene, and immunocompromised individuals.

Pathophysiology

  1. Dermatophytes invade the stratum corneum of the scalp.
  1. The fungus penetrates the hair shaft.
  1. Hair becomes fragile and breaks at or near the scalp surface.
  1. Inflammatory response varies depending on organism and host immunity.

Clinical presentation

Non-inflammatory Tinea Capitis

  • Scalp scaling
  • Patchy alopecia
  • Broken hairs (“black dot” appearance)
  • Minimal erythema or pruritus
Grey Patch (Ectothrix → Microsporum)
Grey Patch (Ectothrix → Microsporum)
Black Dot (Endothrix → Trichophyton)
Black Dot (Endothrix → Trichophyton)

Inflammatory Tinea Capitis

  • Kerion: painful, boggy inflammatory mass
  • Pustules, crusting
  • Tender cervical lymphadenopathy
  • Risk of scarring alopecia
notion image

Favus (severe form)

  • Yellow crusts (scutula)
  • Mousy odor
  • Permanent scarring
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Investigations

  • KOH 10% Examination
    • Shows characteristic fungal true hyphae and arthrospores
  • Wood’s Lamp
    • Green fluorescence (mainly Microsporum species)
    • Trichophyton species usually do not fluoresce
  • Fungal Culture
    • Gold standard for species identification
    • Takes 2–4 weeks

Management


⚠️ Topical therapy alone is ineffective because the fungus infects hair follicles.

Grey Patch — Microsporum

First-line options

  • Griseofulvin
    • 20–25 mg/kgBB/day for 8 weeks
    • Drug of choice in children

Alternatives

  • Terbinafine
    • Weight-based dosing for 4–6 weeks
      • 10-20 kg → 62.5 mg/day
      • 20-40 kg → 125 mg/day
      • >40 kg → 250 mg/day
    • More effective against Trichophyton
  • Itraconazole 50-100 mg/day for 6 weeks

Topical — Adjuvants

  • Selenium sulfide 1% and 2.5% shampoo 2-4x/week
  • Ketoconazole 2% shampoo 2x/day for 2-4 weeks

Black Dot — Trichophyton

  • Terbinafine (first line)
    • Weight-based dosing for 2–4 weeks
      • 10-20 kg → 62.5 mg/day
      • 20-40 kg → 125 mg/day
      • >40 kg → 250 mg/day
  • Griseofulvin 20–25 mg/kg/day for 8 weeks
  • Itraconazole 50-100 mg/day for 2 weeks
  • Fluconazole 6 mg/kg/day for 3-4 weeks