A practical, algorithmic approach to diagnosing hair shaft disorders

Abstract

The hair shaft is a unique structure composed of an inner cortex and a protective outer cuticle. Any defects in this normal structure due to genetics or the environment can lead to variations in physical properties. Thus one should suspect a hair shaft disorder if a patient presents with an abnormality or change in hair texture, appearance, manageability or ability to grow hair long. A key feature of the clinical evaluation is to determine whether there is hair breakage (increased fragility) by looking for broken hairs and performing a tug test.Once this determination is made, an algorithmic approach can be used to narrow the differential diagnosis: hair shaft disorders with and without fragility. A hair mount along with other directed questions and examination will almost always allow the clinician to make an in-office diagnosis. Common case scenarios, photographs, and practical tips are provided to illustrate the use of this algorithmic approach in the diagnosis of hair shaft disorders. We have also included a summary of the molecular defects where known, which can be helpful in providing a correlation with clinical findings, in counseling patients, and potentially offering treatment options.

Clinical Signs of Hair Damage

“…Diagnosis of hair breakage can easily be confi rmed by the 'tug test' [ 22 ]. This can be done by holding with one hand a tuft of hair at 3-4 cm from their tips and tugging with the other hand the same tuft close to the tip.…”

A Practical Approach to the Diagnosis and Management of Hair Loss in Children and Adolescents

“…Patients often present with an inability for appropriate hair elongation, abnormal hair texture, or abnormal hair appearance. To help distinguish between the hair shaft disorders, a tug test can be performed to assess for hair fragility (113). Moreover, light microscopy and trichoscopy can identify features specific to different hair shaft disorders (31, 114).…”

Evaluation of Hair and Scalp Diseases in Pediatric Age Group

“…Tinea kapitis, alopesi areata, traksiyonel alopesi ve trikotillomani bu yaş grubunda en sık saç dökülmesi yapan klinik tanılardır (2). Özellikle 1-3 yaş grubunda görülen kıl şaftı anomalileri de saç dökülmesine sebep olabilir (1,3). Öte yandan, saçlı deriyi tutan seboreik dermatit, psoriasis, atopik dermatit gibi hastalıklarda ise saç dökülmesi nadiren bildirilmiştir (4).…”