Alopecia: Some scientific facts about "Hairfall"!

Visible hair is the end product of cornification of cells of a skin appendage called the hair follicle. The structure of hair follicle is like a cup that gives rise to, supports, and shapes the hair shaft. Ordinarily, there are about 1 lac hair on the scalp. Out of these, normally about 100 are lost everyday. This is because the follicles continually pass through the 3 phase cycles of anagen (growth phase), catagen (phase of decay) and telogen (resting phase). When telogen ends, anagen begins, forming a new hair shaft that pushes the old resting shaft out of the follicle.

Loss of previously existing scalp hair is termed as "alopecia". It may be permanent being accompanied by loss of follicles (scarring) or temporary wherein the follicles are not lost (non scarring). Scarring alopecia occurs due to deep bacterial, viral or fungal infections, discoid lupus erythematosus and scleroderma. Non-scarring alopecia may be inflammatory (tinea capitis) or non-inflammatory which can be localised (alopecia areata) or generalised (androgenetic alopecia, telogen effluvium)

• Alopecia Areata: It is an auto immune disease of hair follicles that affects young adults. It is occasionally associated with atopy and other autoimmune disease, well defined patches of non-scarring, non inflammatory hair loss are characteristic. Any part of scalp or body (e. g. beard, mustache) may be affected. Affection of all scalp hair (alopecia totalis) and all body hair (alopecia universalis) carry bad prognosis. More than 50% cases regrow spontaneously. However, as most patients are worried about the condition, topical or intralesional steroid or topical minoxidil are the first line of therapy. Unresponsive cases can be managed with topical or systematic PUVA or topical DNCB. Systemic steroids are best avoided.
• Androgenetic Alopecia (Common Baldness, Male pattern Baldness): This autosomal dominat trait needs androgens for its expressions. The hair gradually become thinner and finally are lost. In males, it progresses in characteristic pattern (forehead-temples-vertex,gradually all regions coalescing till only a fringe of hair is left over the occiput and even this may be lost). In females, it presents as partial diffuse alopecia that rarely leads to bald patches. Topical minoxidil (2% solution) gives good results in selected patients but needs to be continued to maintain the improvement. surgical options like hair transplant and scalp reduction are avilable for motivated patients.
• Telogen Effluvium: Sudden precipitation of anagen follicles into telogen by major stress (e. g. persistent high fever, difficult labour, major trauma) leads to loss of these telogen hair (10-20% of scalp hair) 2-4 months after the stressful event. Hair grow back spontaneously.