[Paroxismal reactions of the scalp].

The scalp is a unique site of the human body that may exhibit some particular physiopathological reactions. A few manifestations are paroxysmal. The main ones are the acute pruritus of pediculosis, and the pruritus at onset of dandruff or seborrhoeic dermatitis. One must add the telogen effuvium after solar exposure or during the post-partum, and the anagen dystrophic alopecia following chemotherapy. Other paroxysmal events include acute canitia and alopecia areata.