Hair loss occurs when hair growth from the follicles stop. This leads to a reduction in the volume of hair. Hair loss may occur anywhere in the body. If it happens in the scalp, then it can cause a lot of distress for the person. Generally, hair loss develops gradually and patches of baldness show up over a period of time. On average, a person loses fifty to hundred strands of hair in a day, but these get replaced with new ones growing up in the follicle. However, unexplained and excessive hair loss is a cause for worry and may also be an indication of a serious medical condition that needs to be evaluated by a dermatologist. The seven common causes of hair loss are as follows:

Androgenic Alopecia

According to The American Academy of Dermatology, androgenic alopecia is the most common cause of hair loss. Androgenic alopecia refers to the genetic predisposition for hair loss. A person can inherit the gene from either the father’s or the mothers family and is more likely to lose hair if both the father and mother suffered hair loss. Androgenic alopecia is caused due to a genetic sensitivity to dihydrotestosterone, a derivative of the male hormone testosterone. It makes the hair follicles shrink and produce thinner hair. Over time, the shrinking hair follicles stop producing hairs. In the US, about 67% of the men experience some amount of hair loss by 35 years of age. By 50, approximately 85% of the men experience significant thinning of hair. Female pattern baldness can start as early as at puberty, but is more common after menopause. Generally, women experience overall thinning of hair and the frontal hairline remains intact.

Telogen Effluvium

Telogen effluvium refers to a scalp disorder caused due to a major physical or emotional stress that brings about a change in the normal hair cycle. Physical stress may be caused by a surgery, major illness, very high fever and sudden weight change. On the other hand, mental illness, loss of a loved one, divorce and loss of job lead to emotional stress. All hairs go through a growth phase called anagen and a resting phase called telogen. Whereas the growth phase lasts for about 2 – 6 years on the scalp, the resting phase lasts for about 3 months.  At any point in time, 80 – 90% of the hair on the scalp will be in the growth phase and 5 – 15% will be in the telogen phase. A stressful event, physical or mental, induces most hairs to enter the resting phase at the same time. All these follicles shed the hairs a few months later, causing temporary baldness.

Alopecia Induced by Drugs

Toxic effect of drugs can also cause hair loss. Hair loss induced by drugs is a diffuse hair loss and the condition reverses on discontinuation of use of the drug. Temporary or even permanent hair loss in certain cases can be triggered by drugs such as:

Lithium ( as much as 15% of the patients taking the drug are likely to experience hair thinning)

Iodine, thiouracil and thiocyanate (antithyroid drugs)

Valproic acid (anticonvulsants)

Heparin and warfarin (anticoagulants)

Tenormin, Lopressor, Corgard and Inderal (beta blockers)

Salicylates and NSAIDs


Anabolic steroids

Pregnancy and Childbirth

During pregnancy, the estrogen levels remain higher, leading to an extension of the growth phase of the hairs. Many women lose hair heavily after pregnancy as the estrogen levels become normal and a large number of hairs enter into the resting phase. However, the condition improves as the cycle of hair growth returns to normal.

Birth control pills

The use of birth control pills can trigger the mechanism that causes androgenic alopecia. Women using these pills may experience excessive hair loss when starting, changing or discontinuing the medication. Mostly women who are genetically predisposed to hair loss experience hair thinning when they use birth control pills as the associated hormonal changes cause the onset of female pattern hair loss.

Alopecia Areata

Alopecia areata or patchy hair loss is considered to be an autoimmune disease and its cause is not known. A common symptom of alopecia areata is sudden loss of patches of hair. The scalp looks bald and smooth. In most cases, the condition is temporary and hair grows back in a matter of 6 – 7 months. As much as 10% of the people who go through an episode of alopecia areata at some time in their lives are likely to develop new patches or even experience hair loss in the longer term. Males and females are equally affected by this type of hair loss hair loss and can happen at all ages. However, it occurs more commonly in children and adolescents.

Nutritional Deficiency

One of the possible causes of hair loss, especially in women, is iron deficiency. Adequate intake of iron through diet is essential in order to support and maintain hair growth. In women, iron depletion happens during menstruation. Iron deficiency may also happen during pregnancy. If dietary intake of iron is sufficient, supplementation may help. A deficiency of the macronutrient protein in the daily diet can also cause hair loss. The body conserves protein by shifting hairs that are growing into the telogen phase. The hair loss caused due to severe malnutrition can be reversed by maintaining proper intake of protein.

There are a number of causes of hair loss. It is, therefore, important that you consult with a medical doctor who would diagnose the problem and advice suitable treatment. Technological advancements in this area have opened up many treatment options. New and improved medications, shampoos and hair oils are available these days and some of them can be purchased over the counter. However, you need to first decide as to which treatment would best suit your needs. This is because the outcome will depend greatly on your choice of treatment. Natural treatments may be the right choice for people who may want to avoid the side effects of allopathic medication.