Hair Loss Causes

June 11, 2024

Hair Loss Causes

The causes of hair loss can broadly be divided into two types, scarring and non-scarring.

In the scarring type of hair loss, hair roots, and adjacent skin are permanently damaged. The chances of hair growing back naturally at these sites with any medications are near zero. This condition can result from mechanical injury, burn, radiation, and skin diseases like lichen planopilaris, discoid lupus erythematosus, etc.

On the other hand, in non-scarring hair loss hair roots are preserved and hair growth can be expected in bald areas. There are different reasons for non-scarring types of hair loss.

Androgenetic Alopecia (Pattern Baldness)

Androgenetic alopecia also called pattern hair loss is the most common cause of hair loss in which thick hairs gradually become thin and short because of the byproduct Dihydrotestosterone (DHT) of male hormone testosterone.

It is also called a pattern of hair loss because hair loss follows a particular pattern. The male tends to lose hair in the front, crown, and middle part of the scalp but retains hair at the sides and back of the scalp. These retained hairs have the DHT resistant follicles, which are often referred to as the “permanent zone”.

In the case of females, there is a gradual widening of the central parting preserving the frontal hairline. Unlike the male, it involves diffuse hair thinning. Increased androgen production may be a contributing factor in females with pattern hair loss.

Alopecia Areata

Alopecia areata is the condition for hair fall in which a person’s immune system attacks his/her own hair follicles causing hair loss. It presents as smooth circular to oval patches of hair loss over the scalp, beard, eyebrows, or any other body sites.

Telogen Effluvium

In telogen effluvium, the abrupt transition of the hair cycle from the growing phase (anagen) to the shedding phase (telogen) causes diffused hair loss because of the predisposing factor called stressor. If the predisposing factor is not removed, hair fall may be continuous. Below is the list of conditions that can lead to telogen effluvium.

Obstetric and gynecological conditions


Thyroid Disease

Nutritional causes like crash diets, bulimia, protein/calorie deficiency, zinc deficiency, hypervitaminosis A, or essential fatty acid deficiency.

Stress from surgical procedures, general anesthesia, or several emotional problems.

Anagen Effluvium

This is seen in cancer patients who are on anti-cancer drugs. These drugs act on growing hair causing hair fall. It is usually reversible after the stoppage of anti-cancer drugs.

Traction Areata

It occurs when continuous pulling force acts on hair due to tight braiding, ponytails, pigtails, etc.


It is a psychiatric disease where there is an irresistible desire to pull out own hair.