Light microscopic examination of scalp hair samples as an aid in the diagnosis of paediatric disorders: retrospective review of more than 300 cases from a single centre.

BACKGROUND: Microscopic examination of scalp hair can provide important diagnostic information in a range of paediatric conditions. It is a non-invasive and cost effective investigation, which is not widely performed.

AIMS: To examine retrospectively the value of hair examination by light microscopy, including polarising microscopy, in a specialist paediatric pathology department during a 15 year period (1989-2004) and to describe the morphological abnormalities indicative of specific paediatric conditions.

METHODS: Three hundred and twenty two hair samples were submitted. Microscopic changes were analysed in the light of clinical information categorised as: (1) erythroderma, (2) neurological impairment, (3) immunological/haematological defect, (4) ectodermal dysplasia, (5) abnormal hair only, and (6) non-specific/absent clinical details.

RESULTS: Abnormalities were evident in 49% of the samples. In 25%, the changes were compatible with specific diagnoses including Menkes disease, Netherton's syndrome, trichothiodystrophy, Griscelli and Chediak-Higashi syndromes, monilethrix, uncombable hair, and loose anagen syndromes. In respect of the clinical presentation groups noted above, diagnostic changes were seen in 41%, 32%, 33%, 0%, 29%, and 0%, respectively.

CONCLUSIONS: Morphological light microscopic examination of scalp hair is an inexpensive, rapid, and non-invasive investigation, which can provide valuable diagnostic information in a range of paediatric conditions.