Pityriasis amiantacea (PA) is characterized by adherence of hair shafts proximally.1 It has been associated with dermatologic conditions and rarely with medications. We describe a woman who developed PA following a bone marrow transplant with melphalan conditioning. We also review drug-induced PA and disorders that have been linked to this condition.
A 67-year-old woman with a history of multiple myeloma was treated with 7 courses of chemotherapy (cyclophosphamide, bortezomib, prednisone). One month later, the patient underwent a bone marrow transplant with melphalan conditioning due to residual plasma cell myeloma. Following the transplant, she developed complete scalp alopecia. Prior to and following transplant, the patient’s hair care regimen included washing her hair and scalp every other day with over-the-counter “natural” shampoos. During drug-induced alopecia, the hair washing became less frequent.
The patient left the hospital 4 weeks posttransplant; her hair had started to regrow, but its appearance was altered. Posttransplant, the patient was maintained on bortezomib every other week and zoledronate once per month. She continued to develop multiple lesions in the scalp hairs during the following 4 months.
Eight months posttransplant she presented for evaluation of the scalp hair. Clinical examination showed hairs that were entwined together proximally, resulting in matting of the hair (Figure 1). A diagnosis of PA was established based on the clinical examination.
Treatment included mineral oil application to the scalp under occlusion each evening, followed by morning washing with coal tar 0.5%, salicylic acid 6%, or ketoconazole 2% shampoo in a repeating sequential manner. Within 1 month there was complete resolution of the scalp condition (Figure 2).
Pityriasis amiantacea is characterized by thick excessive scale of the scalp1; it was initially described by Alibert2 in 1832. He described the gross appearance of the scales as resembling the feathers of young birds, which naturalists dub “amiante” or asbestoslike.1,2 In 1917, Gougerot3 explored infectious etiologies of this condition by describing cases of impetigo that transitioned into PA.1 Later, in 1929, Photinos4 described fungal origins of PA, giving credence to “tinea amiantacea.”1 However, more recent analyses failed to isolate fungus.5-7 As such, pityriasis (scaling) amiantacea is the more appropriate term, as emphasized by Brown8 in 1948. The cause of PA remains unclear; it is hypothesized that the condition is a reaction to underlying inflammatory dermatoses, though concurrent bacterial or fungal infection may be present.5,9
Pityriasis amiantacea is considered to be most prevalent in pediatric patients and young adults; it is more common in females.1,9,10 In a review of 85 PA patients, more than 80% were women (n=69), and the mean age at presentation was 23.8 years. Approximately half of these patients had widespread scalp lesions (n=42); however, focal localized lesions were common.9 No hereditary patterns have been described, though 3 pairs of the 10 patients with PA in Ring and Kaplan’s7 review were siblings.