We report a case of hair-thread tourniquet syndrome involving the labia majora of a 14-year-old autistic child. 'Hair-thread tourniquet' refers to the process whereby a thread of hair leads to the ischaemic strangulation of an appendage or other piece of tissue. Uncommonly recognized, this syndrome has gradually gained recognition since its first description in 1612. As it remains infrequent, many have attributed its aetiology to abuse or socio-cultural practices. We review the published literature on this infrequent but important paediatric condition.