Is this a dermatophyte infection of the scalp?

June 8, 2010

The mother of this 7-year-old girl originally thought these peculiar scales in her daughter’s scalp and hair were nits, since there had recently been an outbreak of head lice at the child’s school. However, she was not able to find any lice, and the scales resisted removal with mineral oil and a “nit comb.”

Case:

The mother of this 7-year-old girl originally thought these peculiar scales in her daughter's scalp and hair were nits, since there had recently been an outbreak of head lice at the child's school. However, she was not able to find any lice, and the scales resisted removal with mineral oil and a "nit comb."

Do you think this girl has a dermatophyte infection of the scalp?

Answers on Next Page

No, she has pityriasis (or tinea) amiantacea.

Although the characteristic scales of pityriasis amiantacea may resemble tinea capitis (which is why the condition is sometimes referred to as "tinea amiantacea"), the condition is not in any way a dermatophyte infection. The unusual morphological presentation of pityriasis amiantacea is thought to result from the condition's relationship to psoriasis of the scalp. In the majority of affected children, cutaneous psoriasis will eventually develop; however, it is common for this to be the only psoriatic skin change evident for many years.

Clinical appearance. The scales of pityriasis amiantacea are very adherent to the hair and often involve multiple hairs as the scale ascends the hair shaft. The scalp in the involved area is often covered with a thick scale. There is no associated hair loss.

Management. For isolated lesions, I like to use a combination corticosteroid/salicylic acid scalp lotion applied twice daily. For extensive scalp involvement, I recommend an overnight oil/corticosteroid preparation. Because trauma can trigger exacerbations in psoriasis (Koebner phenomenon), I do not recommend any approach to scale removal that might involve vigorous manipulation of the scalp. Sometimes the simplest solution is to cut the affected hairs below the scale and then treat the underlying scalp to prevent recurrence. Unfortunately, pityriasis amiantacea requires ongoing care and treatment, just like psoriasis of the scalp. For further information on the management of scalp psoriasis, see the Dermclinic case of November 2008.1

References:

REFERENCE:

1.

Barber K. Dermclinic.

Consultant For Pediatricians

. 2008;7:457-458.