Objective:

Pityriasis amiantacea (PA) is characterized by thick, silvery, adherent scales, which surround the base of scalp hair. The exact cause of PA is unclear and it is claimed to be a reaction pattern of the scalp to various inflammatory scalp conditions. In this study, we intended to describe the clinical features, to search the microbiologic etiology and to evaluate the associated diseases.

Methods:

Archive files of 47 patients, who had attended to our clinic between January 2009 and April 2010 and diagnosed with PA, were evaluated. Clinical properties, bacteriologic and mycological laboratoary results of all patients and histopathological diagnosis of 36 patients were recorded in the database.

Results:

The study population included 34 (72.3%) female patients and 13(27.7%) male patients and showed a female predominance. Microbiological examination revealed trichopyton spp. from one patient and bacterial isolates from 28 patients(%60). Identification of isolates showed coagulase positive Staphylococcus aureus in 20 patients (%43) and coagulase negative staphylocci in eight patients (17%). Follicular keratosis, diffuse hyperkeratosis and parakeratosis were the common histopathological findings. Pathological diagnosis of seborrehic dermatitis was detected in 20 patients, psoriasis was detected in seven patients, tinea capitis was detected in one patient, bacterial infection was detected in one patient and pemphigus vulgaris in one patient.

Conclusion:

Our study mainly showed an association of PA with seborrheic dermatitis and psoriasis as previously demonstrated but superficial fungal ve bacterial agents should also be kept in mind, since these may have therapeutic implications.

Keywords: Scalp dermatoses, psoriasis, seborrheic dermatitis, tinea capitis, Staphylococcus aureus, pityriasis amiantacea