What Is This Rapidly Growing Scalp Lesion on a 7-Year-Old?

Answer: C. Tinea capitis

Incisional biopsy of the scalp mass was performed with drainage of multiple abscess cavities. Fresh tissue was sent for pathology and microbiology (cultures for aerobes, anaerobes, fungus, and acid-fast stains). Blood samples were evaluated for mycobacterium species, β-d-glucan, and fungi tail via polymerase chain reaction tests.

A positron emission tomography (PET)/CT scan was performed during the same anesthetic, results of which demonstrated a hypermetabolic left occipital soft tissue mass associated with reactive or neoplastic cervical and posterior occipital nodes. The diagnosis of tinea capitis was confirmed on surgical pathology, without evidence of malignancy (cluster of differentiation 1a was negative). Sections showed extensive cellulitis, subcutaneous abscesses, acute folliculitis, perifolliculitis, and pseudoepitheliomatous hyperplasia. Fungal spores, yeast, and hyphae were identified by Grocott's methenamine silver stain and periodic acid-Schiff staining with diastase via the boy’s hair follicles. Cultures were positive for Trichophyton mentagrophytes.

Discussion. Tinea capitis is a common infection that presents with scaling of the scalp, itchiness and patchy alopecia, typically caused by Trichophyton and Microsporum species.^1,2 Trichophyton is the cause of 90% of infections in the United States and is most commonly encountered in ring worm.^1,3 Progressive infection may lead to development of a kerion, which is a severe, inflammatory, abscess-like reaction.^4,5 Kerion often present in the occipital region of the scalp as a solitary lesion with associated reactive cervical and occipital lymphadenopathy.^2,4,6 Although this diagnosis is typically made clinically, gold-standard evaluations include fungal cultures and potassium hydroxide preparations from hair scrapings that demonstrate fungal spores within the hair shaft.² Microsporum infections may also fluoresce green upon Wood lamp examination, while the more commonly identified Trichophyton does not.^2,6

Management of kerion may consist of steroids or systemic antifungal therapy and antifungal shampoos. Use of steroids (prednisolone, 1 mg/kg/d, for 1-2 weeks) to treat the inflammation and minimize scarring is controversial, potentially decreasing the duration of therapy for systemic antifungals.⁷ A 6- to 8-week course of griseofulvin has historically been the gold standard systemic antifungal treatment, although terbinafine, fluconazole, and itraconazole are also recommended.^8,10 In a meta-analysis of randomized clinical trials that examined treatments of tinea capitis, there was no difference in efficacy between griseofulvin (6.25-12.5 mg/kg/day for 8 weeks) and terbinafine (3.125-6.25 mg/kg/day for 4 weeks).⁹ Griseofulvin is more effective for treating Microsporum infections, while terbinafine has been shown to be superior for Trichophyton infections.^9,10 Terbinafine is often given alternatively to griseofulvin because the treatment duration is shorter, the cost is lower, and the efficacy is equal.¹⁰ As topical antifungals do not penetrate the hair shaft, they have not been shown to be an effective treatment for tinea capitis alone and should be used as an adjuvant to systemic therapy.^6,10 Antifungal shampoos, including selenium sulfide (1%-2.5%) and ketoconazole (2%), reduce the spread of infection by killing surface spores.³

Awareness and early recognition of kerion secondary to tinea capitis may minimize unnecessary oncologic investigations, including diagnostic imaging and surgical biopsy, and may prevent sequelae of delayed diagnosis, such as alopecia and permanent scarring.⁶

Patient outcome. Empiric therapy was initiated with a 6-week course of terbinafine and a 1-week course of clindamycin, with delayed initiation of a 3-week course of prednisone (including taper) and a 4-week course of selenium sulfide, 2.3%, shampoo upon confirmation of wound healing.

References

1. Jaspers GJ, Werrij BG, Jagtman BA, Loza B. Severe kerion celsi due to Trichophyton mentagrophytes: a case report. Acta Paediatr. 2011;100(10):e181-e183. https://doi.org/10.1111/j.1651-2227.2011.02256.x

2. Tinea Capitis. In: Mancini AJ, Krowchuk DP, eds. Pediatric Dermatology: A Quick Reference Guide. 3rd ed. American Academy of Pediatrics; 2016; 255-262.

3. Greer DL. Successful treatment of tinea capitis with 2% ketoconazole shampoo. Int J Dermatol. 2000;39(4):302-304. https://doi.org/10.1046/j.1365-4362.2000.00885.x

4. Arenas R, Toussaint S, Isa-Isa R. Kerion and dermatophytic granuloma. Mycological and histopathological findings in 19 children with inflammatory tinea capitis of the scalp. Int J Dermatol. 2006;45(3):215-219. https://doi.org/10.1111/j.1365-4632.2004.02449.x

5. Nakagawa H, Nishihara M, Nakamura T. Kerion and tinea capitis. IDCases. 2018;14:e00418. https://doi.org/10.1016/j.idcr.2018.e00418

6. John AM, Schwartz RA, Janniger CK. The kerion: an angry tinea capitis. Int J Dermatol. 2018;57(1):3-9. https://doi.org/10.1111/ijd.13423

7. Dolder SE, O'Neill BJ, O'Brien MM, Ross AS, Allen RA, Allen HB. A new paradigm in the treatment of kerions: treat the inflammation. Skinmed. 2012;10(1):14-16.

8. Gupta AK, Hofstader SL, Adam P, Summerbell RC. Tinea capitis: an overview with emphasis on management. Pediatr Dermatol. 1999;16(3):171-189. https://doi.org/10.1046/j.1525-1470.1999.00050.x

9. Gupta AK, Drummond-Main C. Meta-analysis of randomized, controlled trials comparing particular doses of griseofulvin and terbinafine for the treatment of tinea capitis. Pediatr Dermatol. 2013;30(1):1-6. https://doi.org/10.1111/j.1525-1470.2012.01866.x

10. Kakourou T, Uksal U; European Society for Pediatric Dermatology. Guidelines for the management of tinea capitis in children. Pediatr Dermatol. 2010;27(3):226-228. https://doi.org/10.1111/j.1525-1470.2010.01137.x