Hair loss (or alopecia) is a natural phenomenon that occurs in all hair-bearing animals during the hair growth cycle. It is estimated that most individuals (assuming their head to be full of hair) lose about 100 strands of hair over a 24-hour period. Hair loss can become a cosmetic problem when it occurs in the wrong place at the wrong time.
The average human scalp has about 100,000 strands of hair. Between 70 and 150 strands of hair are regularly lost from the scalp daily. Hair is lost mainly while washing, brushing and combing. Hair loss or thinning of hair occurs when more strands of hair are lost by shedding than what the scalp is able to renew. Thinning of hair usually becomes apparent after about 40% of the density of hair is lost.
Hair growth cycle
Hair growth occurs in a cycle and the normal cycle of hair growth is between 2 to 3 years. At any point of time, about 90 percent of the hair on the scalp is in a growing phase and about 10 percent of the hair is in a resting phase. After entering the resting phase, the hair falls for about 3 to 4 months after which new hair starts to grow in its place.
Each hair grows about 1 centimetre in a month during the growing phase. Therefore, it is normal to lose some hair daily, but when excessive (more than normal) hair are lost, thinning of hair or hair loss occurs. Hair loss can occur at any age and in both men and women.
Causes of hair loss
There are several causes of hair loss. Some of the common causes include:
Hair loss may be patchy (well-defined areas where hair is lost while the rest of the scalp is covered with hair) or it may be generalised (uniform thinning over the entire scalp).
The different classifications of hair loss include the following:
Treatment of hair loss
Since hair loss can be caused due to several reasons, treatment is influenced by the underlying cause, such as hair loss because of infection or a condition, such as anaemia. In such cases, hair growth improves with treatment of infection or condition. Treatment options for hair loss because of conditions that do improve without treatment include both medicines and surgery. Medicines approved for treatment of hair loss include minoxidil and finasteride. Minoxidil is available as an over-the-counter liquid or foam to be applied locally on the scalp. Finasteride is given orally for treatment of male-pattern baldness. Surgical procedures used for treatment of baldness, such as hair transplant are effective, but expensive and can be painful.