Diagnosis: Kerion Celsi (Inflammatory Tinea Capitis)
The most likely diagnosis for an infant with multiple weeping (seeping) lesions on the scalp is kerion celsi, a severe inflammatory variant of tinea capitis that requires urgent systemic antifungal therapy to prevent permanent scarring alopecia. 1
Clinical Recognition
Kerion presents as:
- Painful, boggy inflammatory masses with associated alopecia
- Pustules studded throughout the lesions with matted thick crust
- Seeping/weeping exudate from multiple follicular openings
- Regional lymphadenopathy (commonly present)
- Lesions may be solitary or multiple 1
Critical pitfall: Kerion is frequently misdiagnosed as bacterial abscess, leading to inappropriate treatment and delayed antifungal therapy 1. While secondary bacterial infection can occur, the primary pathology is fungal.
Causative Organisms in Infants
While tinea capitis is uncommon in infants under 1 year 2, when it occurs:
- Zoophilic species (T. mentagrophytes, T. verrucosum, M. canis) classically cause kerion
- Endothrix infections (T. tonsurans, T. violaceum) increasingly cause kerion in urban areas 1
- The inflammatory response represents delayed host reaction to the dermatophyte 1
Diagnostic Approach
Before initiating treatment, obtain specimens via:
- Scalpel scraping of scale and crust
- Hair plucking from affected areas
- Swab or brush of the lesions 1
Send for:
- Microscopy (KOH preparation) - provides presumptive diagnosis
- Fungal culture on Sabouraud agar - essential for species identification and directing therapy 1
However, in the presence of kerion with cardinal signs (scale, lymphadenopathy, alopecia), it is reasonable to commence treatment while awaiting confirmatory mycology 1. Early treatment is essential to prevent irreversible scarring alopecia 3.
Treatment Algorithm
First-Line Systemic Therapy
Choice depends on suspected organism based on epidemiology:
For suspected Trichophyton species (more common in urban settings):
- Terbinafine:
- <20 kg: 62.5 mg daily for 2-4 weeks
- More effective against Trichophyton than Microsporum 1
For suspected Microsporum species (zoophilic exposure, animal contact):
- Griseofulvin (only licensed option in UK for children):
- <50 kg: 15-20 mg/kg/day for 6-8 weeks
- More effective against Microsporum than terbinafine 1
- Take with fatty meal for optimal absorption
Critical point: Topical therapy alone is NOT recommended and will not achieve cure 1. Oral therapy is mandatory.
Adjunctive Measures
- Do NOT routinely add antibiotics unless clear evidence of secondary bacterial superinfection 1
- Consider short course of oral corticosteroids for severe inflammation (though evidence is limited)
- Antifungal shampoo (ketoconazole 2%) may reduce spore shedding but does not replace systemic therapy
Key Differential Diagnoses to Exclude
In an infant with multiple scalp lesions, also consider:
- Bacterial scalp abscess - but kerion is more common and often misdiagnosed as this 1
- Disseminated gonococcal infection with scalp abscess - rare, associated with fetal scalp electrode use 4
- Diffuse cutaneous mastocytosis - can involve scalp with bullae and crusting 5
- Aplasia cutis congenita - present at birth, not progressive 6
- Seborrheic dermatitis - lacks pustules and inflammatory mass
Monitoring and Follow-Up
- Repeat fungal culture after treatment completion to confirm mycological cure 1
- If no clinical improvement after 2-4 weeks, consider:
- Non-compliance
- Suboptimal drug absorption
- Resistant organism
- Reinfection
- Switch to second-line therapy (itraconazole) 1
Prevention of Permanent Sequelae
Early diagnosis and prompt systemic antifungal therapy are essential to prevent irreversible scarring alopecia 3. The inflammatory response in kerion, while representing host defense, causes follicular destruction if untreated. This is why empiric treatment while awaiting culture results is justified when clinical suspicion is high 1.