Abnormal hair loss, also known as alopecia, refers to the excessive shedding of hair from the scalp or other parts of the body. While it’s normal to lose some hair every day as part of the natural hair growth cycle, abnormal hair loss occurs when this shedding is more pronounced and leads to noticeable thinning or bald patches.

There are several types and causes of abnormal hair loss, including:

1. Androgenetic alopecia: Also known as male or female pattern baldness, this is the most common type of hair loss and is hereditary. It typically occurs gradually with age and is more common in men, although women can also experience it.
2. Alopecia areata: This is an autoimmune condition in which the immune system attacks the hair follicles, leading to sudden hair loss in small, round patches on the scalp or other areas of the body.
3. Telogen effluvium: This type of hair loss occurs when a significant number of hair follicles prematurely enter the resting phase of the hair growth cycle (telogen phase), leading to increased shedding. It can be triggered by factors such as stress, illness, hormonal changes, nutritional deficiencies, or certain medications.
4. Traction alopecia: This type of hair loss occurs when excessive tension is applied to the hair follicles over time, often due to tight hairstyles like ponytails, braids, or extensions.
5. Scarring alopecia: This is a rare form of hair loss characterized by irreversible damage to the hair follicles, leading to scar tissue formation and subsequent hair loss.