Hair loss occurs when hair follicles stop producing hair growth - it is called alopecia.
Hair loss is a normal part of aging. Generally about 100 hairs are lost from your head every day. You may not notice this loss because the average scalp contains about 100,000 hairs. Some people may however experience excessive hair loss.
The normal cycle of hair goes through a phase of growth and rest. Each individual hair survives for an average of three and a half years. The growth phase of hair generally lasts two to three years, during which time it grows about half an inch a month. This growing phase is called anagen. This is followed by a resting phase called telogen, which lasts for about three to four months. Usually in its fourth year the hair falls out and is replaced within 6 months by a new one.
Types of Hair Loss
Pattern Baldness - is inherited or genetic baldness. It is also known as androgenetic alopecia and is caused by the body's failure to produce new hairs, and not due to excessive hair loss. Androgenetic alopecia is generally permanent.
Inherited or "pattern baldness" affects many more men than women. About 25% of men begin to bald by the time they are 30 years old, and about two thirds are either bald or have a balding pattern by age 60.
Male pattern baldness involves a receding hairline and thinning around the crown with eventual bald spots. Ultimately, you may have only a horseshoe ring of hair around the sides. In addition to genes, male pattern baldness seems to require the presence of the male hormone testosterone. Men who do not produce testosterone (because of genetic abnormalities or castration) do not develop this pattern baldness.
Some women also develop a particular pattern of hair loss due to genetics, age or male hormones that tend to increase in women after menopause. The patten is different from that of men. Female pattern baldness involves a thinning throughout the scalp while the frontal hairline remains intact.
In addition to the common male and female patterns, the following are other types of hair loss some of which are temporary:
Alopecia areata - bald patches develop on the scalp, beard, and possibly eyebrows. eyelashes may fall out as well. This is thought to be an autoimmune disease, where the immune system attacks the hair follicles and leads to hair loss on the scalp and other parts of the body. However, the hair follicles are alive so there is potential for hair to regrow when the underlying problem has resolved. Growth may occur even without treatment and even after many years. In most cases hair loss only happens in a few places, leaving a few bare patches. In some cases though, the disease can advance to total loss of hair from the head (alopecia areata totalis) or complete loss of hair on the head, face and body (alopecia areata universalis).
Tinea capitis - is hair loss due to fungal infection of the scalp. This is easily treated with antifungal medicines.
Hormonal changes - an over-active or under-active thyroid gland may cause hair loss. This hair loss stops once the thyroid disease is treated.
Female or male hormone (estrogen and androgen) imbalance can be the cause of hair loss. Once this imbalance is corrected hair loss may stop. Some women may experience hair loss a few months after they've had a baby. This loss is also due to hormonal changes.
Telogen effluvium - is temporary hair loss, which can occur after a serious illness, major surgery or emotional or physical stress.
Anagen effluvium - is hair loss due to treatment with chemotherapy medicines. These medicines target rapidly dividing cells, so affects the actively growing hair cells. Hair grows back after the treatment is finished. This type of hair loss also occurs with radiation therapy but it is localized to the area of treatment. so if treatment is in the hip area you will lose hair in that area but not the hair on your head.
Traction alopecia - certain hairstyles such as when you pull on your hair tightly can cause scarring of the hair follicles. If pulling is stopped before scarring to the scalp then your hair will grow back normally. Nervous habits such as continual hair pulling or scalp rubbing can also cause scarring and ultimately permanent hair loss. Excessive shampooing and blow-drying can also cause hair loss.
Cicatricial or Scarring alopecia - hair loss occurs when inflammation damages and scars the hair follicle and replaces it with scar tissue. The inflammation that destroys the follicle is under the skin surface so affected areas of the scalp may show little signs of inflammation. It is not known what triggers or causes this inflammation. If the inflammation destroys the stem cells and sebaceous glands, then hair loss is permanent.
Diseases - such as diabetes or lupus can cause hair loss.
Trichotillomania - is a psychological condition where the individual has strong urges to pull out their own hair.
Medicines - hair loss can also happen due to medicines such as birth control pills, certain medicines used to treat gout, anticoagulants, antidepressants, etc.
Nutrition - poor nutrition or nourishment can also cause hair loss. Diets, illness, eating disorders would cause poor nutrition.
See your doctor if:
You are losing hair in an atypical pattern.
You are losing hair rapidly or at an early age (for example, in your teens or twenties).
You have any pain or itching associated with the hair loss.
The skin on your scalp under the involved area is red, scaly, or otherwise abnormal.
You have acne, facial hair, or menstrual irregularities.
You are a woman and have male pattern baldness.
You have bald spots on your beard or eyebrows.
You have been gaining weight or have muscle weakness, intolerance to cold temperatures, or fatigue.
Your doctor will take a detailed medical history and will examine the condition of your hair and scalp; this is usually enough to diagnose the nature of your hair loss. Your doctor will also ask questions such as:
Are you losing hair only from your scalp or from other parts of your body as well?
Is there a pattern to the hair loss like a receding hair line, thinning or bald areas on the crown, or is the hair loss throughout your head?
Have you had a recent illness or high fever?
Do you dye your hair?
Do you blow dry your hair? How often?
How often do you shampoo your hair?
What kind of shampoo, hair spray, gel, or other product do you put on your hair?
Have you been under unusual stress lately?
Do you have nervous habits that include hair pulling or scalp rubbing?
Do you have any other symptoms like itching, flaking, or redness of your scalp?
What medications do you take, including over the counter drugs?
Diagnostic tests that may be performed (but are rarely needed) include:
Microscopic examination of a plucked hair
Skin biopsy (if skin changes are present)
Treatment Options For Hair Loss
Treatment depends on the type or reason for hair loss. Effectiveness of these medications may depend on extent of loss and the person's response to a particular medication or procedure.
Hair loss from menopause or childbirth often returns to normal 6 months to 2 years later.
For hair loss caused by illness (such as fever), radiation therapy or chemotherapy, no treatment is necessary. Hair will grow back when illness has ended or the therapy is finished. A wig, hat, or other covering may be desired until the hair grows back.
If a medication is causing hair loss then your doctor may be able to prescribe a different medication to treat your condition (provided an alternative exists).
Pattern Baldness
Although pattern baldness is permanent the following medicines may help slow or prevent the development of common pattern baldness. It can take about 6 months before you see results from these medicines and when you stop using then the former pattern baldness returns.
Propecia (finasteride) is a 5 alpha-reductase inhibitor. It works by inhibiting the conversion of testosterone into 5 alpha-dihydrotestosterone (DHT), a hormone that plays an important role in hair loss. Propecia is a prescription medicine and is only approved for use in men. There are other 5 alpha-reductase inhibitors on the market but Propecia is the only one approved for androgenetic alopecia.
Propecia can cause a decrease in sex drive and sexual function.