Hair loss is a universal occurrence and has a high cosmetic impact on the affected individuals. It is depressing for the sufferer and a headache for the physician, because, except in a few instances, finding the exact cause of the alopecia remains a mirage.
Shedding of hair is known as effluvium or defluvium and the resulting condition is known as alopecia (Greek alopekia for baldness) or hair loss.
Hair Loss Causes
Hair loss causes may be classified into two major types: scarring and non-scarring alopecia.
- In scarring or cicatricial alopecia, there is sign of tissue damage like inflammation, atrophy and scarring in the hair loss area. The hair loss is permanent.
- Noncicatricialor nonscarring alopecia is the commonest type, shows a normal skin structure and usually is amenable to treatment. Nonscarring hair loss can either be diffuse or localized depending upon the area of involvement.
Diffuse Nonscarring Hair Loss Causes
Diffuse non-scarring alopecia is seen to be disseminated throughout the scalp, and, at times, on the body as well. These are caused by
- Failure of hair follicle production due to hormonal and genetic reasons, as in male pattern baldness (the common baldness).
- Hair shaft abnormalities.
- Abnormalities in hair cycling, as seen in telogen effluvium, anagen effluvium, loose anagen syndrome or generalized alopecia areata. Abnormalities of hair cycling occur usually following a prolonged illness, pregnancy, stress and nutritional deficiencies including anemia.
Focal or Localized Nonscarring Hair Loss Causes
Focal, patchy or localized non-scarring alopecia is caused by
- Hair follicle production decline as in focal male pattern hair loss.
- Hair breakage: Trichotillomania, traction alopecia, tinea capitis, hair straighteners etc.
- Abnormal hair cycling: Alopecia areata, secondary syphilis.
How to Differentiate Scarring from Non Scarring Hair Loss?
Close examination of the skin is enough to differentiate the scarring from non scarring alopecia. In scarring alopecia, there is absence of hair follicle opening and increased wrinkling of the involved skin. The skin surface is thin, shiny and dry. Underlying small blood vessels may be visible through the atrophic skin. Towards the periphery of the bald patch, hairs will be twisted because of the pull of the scar tissue.
Scarring AlopeciaCauses
Cicatricial or scarring alopecia may cause hair loss in many hereditary and acquired disorders of the hair and hair follicle.
- Hereditary diseases: Defective development of hair follicles and skin, as in aplasia cutis, darier's disease.
- Traumatic: Chemical and mechanical, as in burns
- Neoplastic: Basal cell carcinoma
- Follicular inflammation: Discoid lupus erythematosus, tinea capitis
- Dermal Inflammation leading to secondary damage to hair follicle, as in morphea, skin tuberculosis, lichen planopilaris etc
From the above review of causes of hair loss, for any treatment of alopecia to be effective, it is evident that a correct diagnosis is essential.
Reference:
- Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, Fifth Ed, 2005
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