Differential diagnosis of hair loss in children.

Hair loss in childhood covers a broad differential diagnosis and often presents the involved dermatologist and pediatrician with a diagnostic and therapeutic challenge. Correct classification of the hair disease, especially in the case of underlying genetic syndromes, metabolic defects or endocrine disorders, is often an important prerequisite for continued normal physical and mental development of the young patients. Dealing with hair loss in childhood, one should differentiate between congenital and acquired diseases. The clinical manifestation profile, the age of the patient when the initial manifestation occurred, and the presence of associated symptoms are important for the classification of the hair disease. In the present paper, a classification of hair loss in childhood based on clinical appearance, age of onset and associated symptoms is proposed as a guide for the evaluation of hair loss and alopecia in childhood.