Anagen alopecia appears to be broken off or tapered. It may occur suddenly due to autoimmune disease, inherited loose anagen syndrome or chemotherapy. If a drug or toxin is removed hair may return within 3 months of the withdrawal. It is significant as it may involve over 85% of the total hair.
Telogen effluvium has a club hair (bulb at the end). It occurs a few months after an event that stops active hair growth e.g., stress, surgery, fever, post-partum. Usually hair growth is limited in quantity <15% and time <6 months. Rarely chronic telogen effluvium may occur. People often complain that their shower drain is full of hair. They bring it into the clinic in classic envelopes. Often reassurance is needed. A work up of thyroid and anemia may be indicated.
Hormonal or hair pattern loss (androgenic alopecia) occurs due to genetics or hormonal influence. It is influenced by androgens. Approximately one half of the population will develop this by age 50. The female pattern will appear like a “Christmas Tree” part with more pronounced hair loss in the anterior scalp. Male pattern balding is seen more at the vertex and temporal scalp.
Scarring alopecia are emergencies of the scalp and must be identified and referred immediately. These categories include lichen planopilaris, lupus of the scalp, scalp scleroderma, dissecting cellulitis and folliculitis decalvans such as that seen in the picture above. Scarring alopecia will result in permanent loss of hair. This gentleman had been kept in primary care for a year before being referred to me. At that point, your best option is simply prevention of progression.