At any one time, about 10% of the hair on your scalp is in a resting phase. After 2 to 3 months, this resting hair falls out and new hair starts to grow in its place. This growing phase lasts for between 2 and 6 years. How long this growing phase lasts determines the length your hair will grow to.

Each hair grows approximately 1cm per month during this phase. About 90% of the hair on your scalp is growing at any one time. It is normal to shed some hair each day as part of this cycle. However, some people may experience excessive (more than normal) hair loss.

What causes excessive hair loss?

A number of things can cause excessive hair loss. For example,

• About 3 or 4 months after an illness or a major surgery, you may suddenly lose a large amount of hair. This hair loss is related to the stress of the illness and is temporary. Your hair will grow back normally over the next few months.
• Hormonal problems may cause hair loss. If your thyroid gland is overactive or under active, your hair may fall out. This hair loss usually can be helped by treatment of the thyroid disease. Hair loss may occur if male or female hormones, known as androgens and oestrogens, are out of balance. Correcting the hormone imbalance may stop your hair loss.
• Many women notice hair loss about 3 months after they've had a baby. This loss is also related to hormones. During pregnancy, high levels of certain hormones cause the body to keep hair that would normally fall out. When the hormones return to pre-pregnancy levels, that hair falls out and the normal cycle of growth and loss starts again.
• If you have iron deficiency anaemia (low blood count because of lack of iron), you may find that your hair starts thinning. Once the Iron deficiency is treated your hair should grow back.
• Some medicines can cause hair loss. This type of hair loss improves when you stop taking the medicine. Medicines that can cause hair loss include blood thinners (also called anticoagulants, e.g. Warfarin), medicines used for gout, medicines used in chemotherapy (to treat cancer), vitamin A (if too much is taken), oral contraceptive pills and antidepressants.
• Certain infections can cause hair loss. Children may lose hair if they get a fungal infection of the scalp. Occasionally this can be quite large and swollen (when it is known as a kerion). The infection is easily treated with antifungal medicines and provided it is treated before scarring develops the hair should grow back normally.
• Alopecia Areata also causes hair loss. This is usually patches of total baldness rather than a diffuse hair loss over the whole scalp.
• Finally, hair loss may occur as part of an underlying disease, such as lupus or diabetes. It is important to see your doctor, particularly if you have other symptoms when your hair starts falling out.

Can you lose your hair if you don't care for it properly?

Yes. If you wear pigtails or cornrows or use tight hair rollers, the pull on your hair can cause a type of hair loss called traction alopecia (pronounced "al-oh-pee-sha").
If the pulling is stopped before scarring of the scalp develops, your hair will grow back normally. However, if scarring occurs, it can cause permanent hair loss.

Hot oil hair treatments or chemicals used in perms may cause inflammation of the hair follicle, which can result in scarring and hair loss.

What is common baldness?

The term "common baldness" usually means male-pattern baldness. Male-pattern baldness is the most common cause of hair loss in men. Men who have this type of hair loss usually have a family history of others in the family going bald. Men who start losing their hair at an early age tend to develop more extensive baldness. In male-pattern baldness, hair loss typically results in a receding hairline and baldness on the top of the head.

Women may develop female pattern baldness. In this form of hair loss, the hair becomes thin over the entire scalp, more noticeably over the top of the head.

Can my GP do something to stop hair loss?

Your GP will probably ask you some questions about your diet, any medicines you're taking, whether you've had a recent illness and how you take care of your hair. If you're a woman, your Doctor may ask questions about your menstrual cycle, pregnancies and menopause. Your GP may want to do a physical exam to look for other causes of hair loss. Sometimes your doctor may do blood tests or very occasionally he may take a biopsy of your scalp.

Treatment for hair loss

Depending on your type of hair loss, treatments are available. If a medicine is causing your hair loss, your GP may be able to prescribe a different medicine. Recognising and treating an infection may help stop the hair loss. Correcting a hormone imbalance may prevent further hair loss. There are medicines that may help slow or prevent the development of common baldness.

Minoxidil: This helps slow down or prevent male pattern baldness. It may also be used to treat female pattern baldness. This medicine is available without prescription in 2 percent and 5 percent strengths, and in stronger prescriptions with a GP's prescription.

It is in liquid form and is applied to the scalp twice daily. Its effectiveness varies from person to person. Generally 25% of men and 20% of women have some hair regrowth. This new hair is usually thinner and lighter in colour and is sometimes like baby hair. It is recommended that people stop treatment if they do not experience any significant results within 6 months. Minoxidil should not be used for hair loss due to illness or childbirth.

Side effects include some dryness and irritation of scalp. Minoxidil can occasionally cause problems in people with heart disease; therefore if you have heart disease you should discuss this with your doctor before use. Such people must not use the medicine without their cardiologist's permission.
Finasteride This is a prescription only medicine and comes in the form of pill. This medicine is for men only. It usually takes about six months to start working.
Treatment should be stopped if no significant improvement is visible after 12 months. In clinical studies, 80 percent of men experienced slowing for hair loss, 66 percent had visible regrowth. Finasteride is not approved for use in women because it may cause serious birth defects in male foetuses. In fact, pregnant women should not even handle broken or crushed tablets due to the danger of drug absorption. No side effects have been observed in women whose husbands and partners have been using this drug.

Surgical strategies

If drugs are ineffective in slowing down or preventing baldness, there are two surgical procedures available to treat baldness:
Hair transplants: An expert takes tiny plugs of skin containing several hairs from an area of scalp where the hair is still present. These plugs are implanted into the bald sections of the scalp. Hair growth from the transplant requires 4 to 6 months.

Scalp reduction: Scalp reduction means decreasing the area of bald skin on your head. The hairless skin is stretched and surgically removed and the space is closed with hair-covered scalp. Scalp reduction and hair transplants can be used in combination with each other as well.

Surgical procedures to treat baldness are expensive and not covered under most insurance plans. They also can be time consuming. A very small percentage of patients experience chronic head pain afterward. There is a slight risk of infection as with any surgery.