Hair Loss

Alopecia or hair loss is the medical description of the loss of hair from the head or body, sometimes to the extent of baldness. Unlike the common aesthetic depilation of body hair, alopecia tends to be involuntary and unwelcome, e.g., androgenic alopecia. However, it may also be caused by a psychological compulsion to pull out one's own hair (trichotillomania) or the unforeseen consequences of voluntary hairstyling routines (mechanical "traction alopecia" from excessively tight ponytails or braids, or burns to the scalp from caustic hair relaxer solutions or hot hair irons).

In some cases, alopecia is an indication of an underlying medical concern, such as iron deficiency.[1]

When hair loss occurs in only one section, it is known as alopecia areata. Alopecia universalis is when complete hair loss on the body occurs, similar to how hair loss associated with chemotherapy sometimes affects the entire body.

Causes
Androgenic alopecia (Male pattern baldness)
Fungal infection such as "black dot" tinea or tinea capitis
Chemical breakage such as over processing, or frequent use of chemical relaxer
Heat damage as from repeated hot comb use
Chronic exposure to traction on hair shaft such as Traction alopecia
Compulsive hair pulling such as trichotillomania
Hyperthyroidism or Hypothyroidism [3]
Iron deficiency
Telogen effluvium resulting from physical or psychological stress
Hereditary disorder of the hair shaft or genodermatoses
Secondary syphilis can cause "moth eaten hairloss"[4]
Discoid lupus erythematosus or chronic cutanous lupus erythematosus
Lichenplanopilaris
Pseudopelade of Brocq
Tufted folliculitis
Dissecting cellulitis
Alopecia mucinosa
Keratosis follicularis spinulosa decalvans
Adverse effect from certain drugs such as chemotherapy
Radiation therapy
Testosterone booster tablets.