Tinea Capitis (Pediatric)

Definition

Tinea capitis is a superficial fungal infection of the scalp and hair shafts in children, caused primarily by dermatophytes, leading to hair loss, scaling, and sometimes inflammation.

Epidemiology

• Most common in children aged 3–7 years
• Boys are affected more frequently than girls
• Higher prevalence in African and African-American children
• Transmission via direct contact with infected individuals, animals, or fomites
• Incidence peaks in crowded living conditions and poor hygiene

Etiology

• Dermatophytes: Trichophyton tonsurans, Trichophyton violaceum, Microsporum canis
• Transmission through direct contact with infected scalp, hair, or pets
• Fomites: combs, hats, bedding
• Environmental factors: warm, humid climates facilitate fungal growth
• Immunodeficiency or chronic illnesses may increase susceptibility

Pathophysiology

• Fungal spores adhere to scalp and hair shafts
• Fungi invade keratinized tissue using keratinases
• Host immune response triggers inflammation and scaling
• Hair shaft infection leads to breakage and alopecia
• Inflammatory variants (kerion) involve intense immune response with pustules
• Chronic infection can lead to scarring alopecia if untreated