Hair loss carries with it a tremendous emotional and psychological burden for the patient.1 It can also be very daunting both diagnostically and therapeutically for the clinician. With entities ranging from Shokeir syndrome to citrullinaemia, the differential diagnosis of alopecia overwhelms at first blush. Fortunately, when we focus on children, especially otherwise healthy children with previously normal hair, the considerable number of possibilities falls precipitously and we are left with a not-so-daunting few.

In this review, we will focus on four of the most common causes of alopecia in children: telogen effluvium, trichotillomania, tinea capitis and alopecia areata.2 Although perhaps seemingly straightforward, there are a number of pearls and perils in sorting out these entities and selecting treatment that I hope to explore.

INTRODUCTION

Telogen effluvium refers to an abnormality of the normal hair cycle that results in excessive loss of telogen or resting-stage hairs.3 It is usually acute and self-limited and frequently occurs after an illness or stressful event, but can also be related to medications, child birth and thyroid disease.3

Trichotillomania (sometimes preferentially referred to as trichotillosis as the suffix mania can connote insanity4) refers to habitual hair pulling and may fall into the spectrum of obsessive-compulsive disorders or, perhaps, can be conceptualised as a type of addiction.5

Tinea capitis (ringworm of the scalp) is a highly-contagious dermatophyte fungal infection of the scalp and hair. Although the commonest cause of tinea capitis worldwide remains Microsporum canis, starting about 20 years ago in the USA and more recently in the UK, the epidemiology has shifted such that greater than 90% of cases are now caused by Trichophyton tonsurans.6

Alopecia areata is a common, usually patchy …