Poor nutrition. Having inadequate protein or iron in your diet or poor nourishment in other ways can cause you to experience hair loss. Fad diets, crash diets and certain illnesses, such as eating disorders, can cause poor nutrition. Inadequate protein in diet – Some people who go on crash diets that are low in protein, or have abnormal eating habits, may develop protein malnutrition. The body will save protein by shifting growing hair into the resting phase. Massive hair shedding can occur two to three months later. Hair can then be pulled out from the roots fairly easily. This condition can be reversed and prevented by eating the proper amount of protein and, when dieting, maintaining adequate protein intake.
Shampooing, combing and brushing too often can also damage hair, causing it to break. Using a cream rinse or conditioner after shampooing will make it easier to comb and more manageable. When hair is wet, it is more fragile, so vigorous rubbing with a towel, and rough combing and brushing should be avoided. Do not follow the old rule of 100 brush strokes a day that damages hair. Instead, use wide toothed combs and brushes with smooth tips.
Hormonal problems may cause hair loss. If your thyroid gland is overactive or underactive, your hair may fall out. This hair loss usually can be helped by treatment thyroid disease. Hair loss may occur if male or female hormones, known as androgens and estrogens, are out of balance. Correcting the hormone imbalance may stop your hair loss.
Hair cosmetic use or improper hair care – Many men and women use chemical treatments on their hair, including dyes, tints, bleaches, straighteners and permanent waves. These treatments rarely damage hair if they are done correctly. However, the hair can become weak and break if any of these chemicals are used too often. Hair can also break if the solution is left on too long, if two procedures are done on the same day, or if bleach is applied to previously bleached hair. If hair becomes brittle from chemical treatments, it is best to stop until the hair has grown out.
Certain infections can cause hair loss. Fungal infections of the scalp can cause hair loss in children. The infection is easily treated with antifungal medicines
Childbirth – When a woman is pregnant, more of her hair will be growing. However, after a woman delivers her baby, many hairs enter the resting phase of the hair cycle. Within two to three months, some women will notice large amounts of hair coming out in their brushes and combs. This can last one to six months, but resolves completely in most cases.