The role of psychological factors and serum zinc, folate and vitamin B12 levels in the aetiology of trichodynia: a case-control study.

BACKGROUND: Cutaneous dysaesthesia syndromes are characterized by chronic cutaneous symptoms without objective findings, and their aetiologies are obscure. Trichodynia describes pain and a stinging sensation of the scalp related to diffuse alopecia. AIMS: To determine the prevalence rate of trichodynia in patients with diffuse alopecia; to assess the serum zinc, folate and vitamin B(12) levels; and to investigate the significance of psychological disorders in these patients. METHODS: The study comprised 91 patients with a diagnosis of diffuse hair loss and 74 healthy controls. Patients were questioned about the presence of trichodynia, and their serum zinc, folate and vitamin B(12) levels were assessed. They were also evaluated using the Beck Depression Inventory (BDI), the Beck Anxiety Inventory, and the Somatoform Dissociation Questionnaire (SDQ). RESULTS: The rates of androgenetic alopecia and telogen effluvium were 26.4% and 73.6%, respectively, Trichodynia was found in 30 patients (33%), and was more common in the telogen effluvium group than in the androgenetic alopecia group (P = 0.5). There was no significant difference between the patients with alopecia and controls for zinc, folate and vitamin B(12) levels, or for psychological test scores. However, the BDI and SDQ scores were significantly higher (P = 0.03 and P = 0.01, respectively) in patients with than those in without trichodynia. CONCLUSIONS: Trichodynia is a commonly encountered symptom in patients with diffuse alopecia, and depression and somatoform dissociation disorders may play an important role in its aetiology. Our data provide no evidence that serum levels of zinc, folate or vitamin B(12) are involved in the pathogenesis of trichodynia.