On an average hair grows about 13 mm a month. They grow more at night than day and faster in summer than winter. Healthy adults normally shed between 50-100 hairs each day.

The following are some of the causes: 

1.Hereditary

2.Severe illness

3.High fever

4.Nutritional deficiencies.

5.Scalp infections

6.Stress

7.Certain drugs like cytotoxic anti-cancer drugs and strong anti-biotics Hormonal changes esp. during pregnancy and also after leaving the contraceptive pill.

8.Certain chemicals, like those used to purify swimming pools.

9.Wear and tear of over-grooming.

10.Bleaching. Repeated bleaching with hydrogen peroxide can cause split ends

11.Perming and dyeing. Temporary dyes are not as harmful as permanent dyes which can damage the hair shaft.

Symptoms:

Sudden or gradual change in any of the 4 factors: Density, texture, pattern and colour. Broken hair or split ends.

Do's and Don'ts:

Recognize signs of stress and identify the causes. At work reduce stress by learning to avoid long hours, not accepting unrealistic demands, setting realistic goals, accepting changes optimistically and not taking work related problems home. 

At home, share your grievances, share your problems and regular weekend breaks with the family. Your diet should be balanced in vitamins, minerals and proteins. Avoid using dyes, bleaching and perming hair. Avoid washing your hair too frequently. To avoid split ends snip off the ends cleanly every 2 weeks. Otherwise, the split may travel backwards to the root. Avoid tight hair styles or elastic hair bands. Do not use heated, spiked rollers frequently and never hold the hair dryer too close to the scalp (at least 15 cms away). Never use sharp combs or brushes. Never brush or comb when the hair is wet and always use a towel to dry it gently. Avoid over-zealous scalp massage or brushing.