Alopecia is an umbrella term for hair loss of any type.
Androgenetic Alopecia (AGA) is a type of hair loss due mostly to hormones, and is the most common form of hair loss.
Although androgenetic alopecia is called male pattern hair loss, it affects 45% of women.
Alopecia is divided into two sub-classes such as scarring alopecia and non-scarring alopecia. Alopecia, which leaves a scar on the skin, is of a rarer type.
Androgenetic Alopecia: It is the most common type of alopecia. It occurs due to genetic predisposition and hormones. Androgenetic alopecia, which is observed in men in their twenties, is mostly observed in women in their forties. While men typically start to lose their hair from the front and sides, women are typical for a Christmas tree-like shedding.
- Alopecia Areata: Loss of hair in any part of the body and in a specific area. It can affect the scalp as well as other areas such as arms, legs and eyebrows. Although the cause is not fully understood, it is thought to occur when the body defends against its own cells (autoimmune disease). For this reason, it is common to apply local steroids to the areas where it is observed.
- Traumatic alopecia: It occurs when the hair is pulled strongly and exposed to trauma. It is common in performers of various kinds. The shedding seen in trichotillomania disease, in which people constantly pull their hair, is also considered within this type.
- Telogen effluvium: Our hair maintains their lives in a cycle. The growth phase is called anagen, the stagnation phase is called katagen, and the resting phase is termed telogen. In a normal person, 80% of the hair is in anagen phase, 2% in katagen phase and 18% in telogen phase. If the percentage of hair in the anagen phase decreases while the percentage of telogen phase increases, it is called as telogen effluvium. Thyroid dysfunction, an iron-deficient diet, not taking essential vitamins and minerals and some medications can cause telogen effluvium.
- Traction (pulling) style alopecia: It occurs when women tightly tie their hair. It is more common in African-American women. Typically manifested by thinning on the front line and sides.
- Chemotherapy induced alopecia: This is also called anagen effluvium. In most of the cases, the hair returns to normal after the treatment is over.
In the most common type of alopecia, hair follicles first become thinner and then baldness occurs. Although testosterone is known as a male hormone, it plays a large role in female hair loss as well.
70% of men and 45% of women are affected by this type of hair loss (androgenetic alopecia). Testosterone is converted into a hormone called dihydrotestosterone.
In a significant part, hormone levels are completely normal. This is because a large part of dihydrotestosterone is produced in the hair follicles and very little passes into the systemic circulation from there.
Dihydrotestosterone binds to receptors in hair cells and sends signals inside the cell. It increases hair loss on the scalp and increases hair growth in other body parts.
Treatments for all kinds of alopecia can be found here!