Alopecia classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ogechukwu Hannah Nnabude, MD

Alopecia can be subdivided into two main categories: non-scarring and scarring. Over all, non-scarring alopecia has a higher possibility of being reversible and having a better outcome while scarring alopecia is more likely to be irreversible and have a poorer outcome.

Alopecia may be classified according to the scarring into 2 subtypes/groups: non-scarring and scarring.
The six major categories of non-scarring alopecia are:

• Alopecia areata: this can affect any part of the body. When it affects only a portion of an area of the body, it is called alopecia areata. When it affects the entire site, it is called alopecia totalis. When it involves the whole body, it is called alopecia Universalis. The etiology is unknown, but it might be related to an autoimmune disease.^[1]

• Anagen effluvium: This is hair shedding that occurs during the anagen phase of the cell cycle. Seen in cancer patients who are receiving chemotherapeutic agents.

• Androgenetic alopecia: is a pattern of hair loss that is affected by hormones and genes.

• Telogen effluvium: results from shifting of hair growth cycle from the anagen phase towards the telogen phase. It may result from an illness like hypothyroidism or hyperthyroidism. Also, it can arise from stress like major surgery or severe psychological stress ^[2]. Other causes include drugs, crash diet, poor feeding. ^[3]

• ”’Tinea capitis”’: the classical kind of tinea capitis (black-dots) causes non-scarring hair loss, unlike other types like kerion and favus.

• Traumatic alopecia: This results from forceful traction of the hair. It is commonly seen in children and is similar to traction alopecia. Also, trichotillomania is a type of traumatic alopecia in which the patient pulls on his/her hair repeatedly. ^[4]

Scarring alopecia is divided into three major types:

• Alopecia mucinosa: This occurs when mucinous material accumulates in the hair follicles and the sebaceous glands. The mucinous material causes an inflammatory response that hinders the growth of hair.

• ”’Alopecia neoplastica”’: This occurs when there is metastatic infiltration of the scalp hair with malignant cells.

• ”’Tinea capitis”’: This is the inflammatory variety of tinea capitis (favus) or kerion, which is when the fungi cause abscess formation, which may culminate with scarring alopecia.

• Other causes of hair loss that occurs with scarring or inflammation include systemic lupus erythematosus, radiation therapy, and sarcoidosis. ^{[2] [5]} Diagnosis of hair loss is partly based on the areas affected. ^[5]