PITYRIASIS

 

AMIANTACEA

 

Pityriasis amiantacea (synonyms: tinea amiantacea, asbestos scalp, porrigo amiantacea, tinea asbestina, keratosis follicularis amiantacea) is the name given to a disease of the scalp in which heavy scales extend onto the hairs and separate and bind together their proximal portions..

Pityriasis amiantacea is a reaction of the scalp, often without evident cause, that may occur at any age. It may be observed as a complication or sequel of streptococcal infection, seborrheic dermatitis, atopic dermatitis, lichen simplex, and it also occurs in psoriasis, of which it may be the first clinical manifestation.The process may be circumscribed or diffuse. It is only slightly inflammatory with dry, micaceous scales, or markedly inflammatory with admixture of a crust . Removal of the scales reveals normal or erythematous edematous epidermis. The process is not followed by atrophy, scarring, or alopecia. If scarring alopecia occurs, it may be related to secondary infection. A common form complicates chronic or recurrent fissuring behind one or both ears, mostly in young girls. The sticky scales extend several centimeters into the neighboring scalp. Another form extends from patches of lichen simplex and is seen mainly in middle-aged women