A 7-year-old black girl comes toyour office with a 10-week historyof scaling and scalp redness,and hair loss. About 3 weeks beforethe visit, the child’s motherfirst noticed a boggy, drainingyellow plaque on her daughter’sparietal scalp. A different physicianprescribed ketoconazoleshampoo. At 1-week follow-up,the symptoms had not abated;the clinician then prescribed oralcephalexin as well as a topical mixture of the antifungal agent, clotrimazole, and the high-potency topicalcorticosteroid, betamethasone. After 2 weeks of therapy, the symptoms were no better.
PATIENT PROFILE:A 7-year-old black girl comes toyour office with a 10-week historyof scaling and scalp redness,and hair loss. About 3 weeks beforethe visit, the child's motherfirst noticed a boggy, drainingyellow plaque on her daughter'sparietal scalp. A different physicianprescribed ketoconazoleshampoo. At 1-week follow-up,the symptoms had not abated;the clinician then prescribed oralcephalexin as well as a topical mixture of the antifungal agent, clotrimazole, and the high-potency topicalcorticosteroid, betamethasone. After 2 weeks of therapy, the symptoms were no better.
The girl's mother reports that the scalp lesion has grown larger, despite therapy (Figure 1). You notethat the child has cervical adenopathy.
WHAT WOULD YOU DO NOW?A. Order a Tzanck smear and viral culture.
B. Order a swab for bacterial culture.
C. Perform a potassium hydroxide preparation or dermatophyte culture.
D. Perform a skin biopsy and tissue culture.
E. Order a deep fungal and atypicalMycobacterium culture.
THE CONSULTANT'S CHOICE
The clinical appearance of this patient's scalp couldbe the result of a variety of disorders. The leading diagnosticcontenders include a bacterial abscess, seborrheicdermatitis, scalp psoriasis, and fungal infection with kerionformation. You suspect a fungal infection because ofthe cervical adenopathy and the fact that the lesion andsymptoms have been unresponsive to antibiotics and topicalcorticosteroids. Thus, the most appropriate diagnostictest is a potassium hydroxide preparation (KOH) or dermatophyteculture (Choice C). Microscopic examinationof a KOH preparation of scrapings taken from the scalpplaque and of some of the broken-off hairs from aroundthe lesion is key to the diagnosis of fungal infection.
In this patient, the KOH preparation revealed hyphae,which confirmed the presence of fungal infection of thescalp.
A Tzanck preparation and viral culture (Choice A)are not indicated here. These are used to confirm the diagnosisof some viral infections, including herpes simplexinfection, which classically appears as grouped vesicles onan erythematous base. A routine swab for bacterial culture(Choice B) is not the best choice in this setting, becausea true bacterial abscess is rare in children.
Choice D-skin biopsy and tissue culture-wouldyield the diagnosis of fungal infection. However, this approachis overly aggressive in this setting. Tissue culturesare usually reserved for diagnosis of deep fungal infectionsor atypical skin infections.
Choice E-deep fungal and atypical Mycobacteriumculture-is not indicated for a superficial fungal infectionlike the one this patient appears to have.
WHAT WOULD YOU DO NOW?
Based on the KOH results, which of the following isthe most likely diagnosis?
A. Dissecting cellulitis of the scalp.
B. Bacterial scalp abscess.
C. Tinea capitis with kerion formation.
D. Secondary syphilis.
E. Pityrosporum folliculitis.
THE CONSULTANT'S CHOICE
The demonstration of hyphae on the KOH preparationconfirms the diagnosis of tinea capitis with kerionformation (C). The kerion, which manifests as a yellow,boggy, nontender scalp mass, indicates long-standingdermatophytic infection; this lesion is a manifestation ofan intense inflammatory response to the fungus.
The KOH results and fungal culture rule out suchmimics as dissecting cellulitis, secondary syphilis, andPityrosporum folliculitis.
Trichophyton tonsurans is the chief cause of tineacapitis infections; it is responsible for more than 90% ofcases in this country. T tonsurans causes an infection withinhair shafts (Figure 2); this fungal infection is prevalentamong young black and Hispanic children and in youngsterswho live in urban areas. (Adolescents and adults arerarely infected.) The fungus spreads readily from childto child via contact with infected hairs and epithelial cells(eg, by sharing a comb, a hat, a towel, or bedding); if onechild in the household has T tonsurans infection, thereis a significant chance that siblings will also be infected.
A minority of tinea capitis infections are causedby Microsporum canis. This is the classic dog and cat"ringworm."
WHAT WOULD YOU DO NOW?A. Prescribe ketoconazole shampoo and atopical corticosteroid for 6 weeks.
B. Treat with 5 mg/kg of griseofulvin for8 to 12 weeks.
C. Treat with 15 to 20 mg/kg of griseofulvin for8 to 12 weeks.
D. Treat with 1 to 2 mg/kg of oral prednisonefor 1 week.
E. Give an oral antibiotic, such as cephalexin.
F. Options C and D.
THE CONSULTANT'S CHOICE
For a patient who has tinea capitis with kerion, choice
is the most appropriate treatment option.Tinea capitis is best treated with 15 to 20 mg/kg oforal griseofulvin until the infecting organism is completelyeradicated--usually within 8 to 12 weeks. The manufacturerrecommends a dose of approximately 5 mg/kg for childrenwith tinea capitis; nevertheless, most dermatologistsuse the higher dose in this setting. (I prefer the capsulesor pills instead of the suspension; the medication is betterabsorbed when taken with a fatty meal, and patients seemto get better results.)Griseofulvin is relatively well tolerated. Adverseeffects are rare, but may include nausea, vomiting, headache,photosensitivity, hepatotoxicity, and blood dyscrasias.Given that this antifungal medication is sometimesneeded for up to 3 months, patient noncompliance is aserious problem. A single daily dose of the medicationmay enhance compliance.For patients with kerion, give 1 to 2 mg/kg oforal prednisone for 1 week in addition to the griseofulvin.Patients who have not had long-term infections often presentto their pediatrician with far less dramatic scaling,redness, and some hair loss. In such mild cases, oral prednisoneis not needed.Choice A is incorrect. Shampoo is ineffective inpatients with tinea capitis. Also, the application of a topicalcorticosteroid will greatly aggravate the infection. (Theeffect is analogous to fertilizing a garden.)Oral antibiotics (Choice E) are seldom needed inthe treatment of a kerion. These are indicated only if thereis an obvious secondary staphylococcal or streptococcalinfection.
Patients with tinea capitis need to beseen every 2 to 4 weeks. At each visit, look for signs of decreasederythema and scaling, renewed hair growth,and reduced cervical adenopathy. Reculture is indicated ateach follow-up visit; continue the griseofulvin for 2 fullweeks after the last negative culture.
What about siblings?
Given the rapidity with which
infection spreads among children, considerthe likelihood that the patient's siblings will also be infected.It is prudent to examine siblings and to do a scrapingand culture; however, treatment is not indicated in theabsence of a positive culture or KOH preparation.
There are currently a numberof studies under way involving use of alternative agents togriseofulvin.
In particular, the efficacy of fluconazole,terbinafine, and itraconazole in tinea infections is under investigation.(Fluconazole has been approved for the treatmentof thrush in children, but it is not currently indicatedfor tinea capitis.) These agents have an affinity for keratinizedstructures, such as the hair shaft and nails. It maybe possible to pulse dose these medications or to givethem for a shorter period than griseofulvin; this may resultin better patient compliance and, consequently, a bettercure rate.
REFERENCES:1. Friedlander SF, Aly R, Krafchik B, et al. Terbinafine in the treatment ofTrichophyton tinea capitis: a randomized, double-blind, parallel-group, durationfindingstudy. Pediatrics. 2002;109:602-607.
2. Chen BK, Friedlander SF. Tinea capitis update: a continuing conflict with anold adversary. Curr Opin Pediatr. 2001;13:331-335.
3. Gupta AK, Adam P, Hofstader SL, et al. Intermittent short duration therapywith fluconazole is effective for tinea capitis. Br J Dermatol. 1999;141:304-306.
4. Abdel-Rahman SM, Powell DA, Nahata MC. Efficacy of itraconazole inchildren with Trichophyton tonsurans tinea capitis. J Am Acad Dermatol. 1998;38:443-446.