Twenty percent present with their first patch over the age of 40 and twelve percent present with their first patch past the age of 50. One can classify alopecia areata based on extent of disease or pattern of hair loss. In alopecia totalis, all the scalp hair on the scalp is lost, and the surface of the scalp becomes totally smooth. Alopecia universalis means loss of all hair on the head and body, including eyelashes, eyebrows, underarm hair, and pubic hair. Alopecia areata can also be classified by the pattern of hair loss.
Circumscript type means localized patch of hair loss.
Reticulated type means that is there is a net-like pattern of hair loss in which irregular areas without hair are interspersed with areas of hair on the scalp. Ophiasis comes from the Greek word serpent. It is a pattern of hair loss that covers the periphery of the scalp like a serpent forming a turban over the edges of the scalp. This type of hair loss is more difficult to treat and this area of the scalp is more sluggish to treatment. Diffuse form of alopecia areata means a form of incomplete hair loss affecting the whole scalp without distinct patches.