The word "areata" means "patchy."
Alopecia areata is an autoimmune disease that causes hair loss in specific areas. It is a non-scarring form of alopecia that can affect the scalp, face, or entire body.
| Type | Description |
|---|---|
| Alopecia Areata | Patchy hair loss |
| Alopecia Totalis | Complete hair loss on the scalp |
| Alopecia Universalis | Complete hair loss over the entire body |
| Diffuse Alopecia Areata | Hair loss without visible patches β difficult to diagnose |
| Ophiasis | Hair loss on the sides of the head and lower back of the neck |
| Alopecia Barbae | Hair loss in the beard and mustache area |
In autoimmune diseases, the body mistakenly attacks its own healthy cells β in this case, hair follicles. Immune system cells (a specific group of T cells called NKG2D+ T cells) accumulate around the follicles and attack them, disrupting hair growth.
The exact mechanism is not yet fully understood.
Since the cause of alopecia is related to the immune system, there is currently no cure that completely eliminates this condition. However, treatment options exist that promote hair growth or reduce immune system activity, such as corticosteroids, topical agents, and targeted therapy drugs.
Although alopecia does not affect physical health, it can significantly impact a personβs self-esteem, mental health, and overall well-being.
Around 10-50% of people with alopecia areata also experience nail changes β most commonly pitted depressions and ridges on the nail surface.
Alopecia areata can affect both men and women of any age. About 50% of cases start in childhood. Around 1 in 1000 people have some form of alopecia areata, regardless of ethnicity.
Family history of alopecia areata and/or other autoimmune diseases is present in 10β25% of patients. People with alopecia areata are at a higher risk of developing other autoimmune diseases (such as thyroid diseases, vitiligo) and atopic conditions (eczema, asthma, allergic rhinitis, etc.).
Alopecia areata is more common in people with chromosomal disorders, such as Down syndrome.
This condition is considered polygenic, meaning that a child must inherit a specific set of genes from both parents to develop alopecia areata.
However, the presence of genes alone does not mean the disease will develop. Most dermatologists believe that a trigger is needed to initiate hair loss.
π§ The exact mechanism is not clear, but possible triggers include:
Internal:
External:
The diagnosis is made by a doctor. Sometimes additional tests are needed β trichoscopy (scalp and hair examination under a microscope) or skin biopsy.
Alopecia areata does not cause permanent hair loss. Hair follicles are not destroyed, and there is a chance that hair will grow back.
In the case of patchy forms, hair typically regrows within months or years, but complete regrowth cannot be guaranteed.
For many people, hair fully regrows. However, if the disease progresses to the totalis or universalis form, the likelihood of full regrowth decreases.
Hair loss often occurs in waves throughout life.
Currently, there is no cure for alopecia areata, but there are several treatment options β unfortunately, none are guaranteed.
For many people, hair regrows even without any treatment.
Treatment is often more successful in milder cases where hair loss is limited to specific areas.
Most common treatments:
Approximately 20% of cases are inherited. It is polygenic, meaning that multiple genes influence the condition.
However, the presence of genes alone does not mean the disease will develop. Environmental factors also play an important role.
Most children with alopecia areata do not have parents with this condition, so most people do not pass it on to their children.
Androgenic alopecia is the most common type of hair loss in both men and women. It is genetically and hormonally influenced hair loss, often referred to as:
| Gender | Affected Percentage |
|---|---|
| π¨ Men over 50 | ~50% |
| π© Women over 65 | ~50% |
Hair on the head typically grows in bundles β usually 3-4 hairs per follicle. In androgenic alopecia, the following occurs:
A doctor typically diagnoses androgenic alopecia by examining the pattern of hair loss on the scalp. They may also perform blood tests to measure hormone levels, serum ferritin, and thyroid function.
Androgenic alopecia is a combination of genetic and hormonal factors, many of which are not fully understood. This hair loss is associated with hormones called androgens, particularly dihydrotestosterone (DHT). Elevated androgen levels, such as DHT in hair follicles, can shorten the hair growth cycle and cause hair to grow shorter and thinner. Follicles may also remain in the resting phase for longer periods.
Although researchers believe several genes play a role in the development of androgenic alopecia, only one gene has been associated β the androgen receptor gene, which is linked to the development of androgenic alopecia. Androgen receptors allow the body to respond to dihydrotestosterone and other androgens. Studies suggest that changes in the androgen receptor gene result in more active androgen receptors in hair follicles. However, it is unclear how these genetic changes increase the risk of hair loss in both men and women with androgenic alopecia.
Androgenic alopecia is not fully treatable. However, its impact can be slowed with treatment. In men, possible treatments include oral finasteride and/or topical minoxidil solution or foam, while in women β topical minoxidil solution or foam. Hair transplantation can also be used to improve the appearance of androgenic alopecia (click here for more information on hair transplants).
It is difficult to say if androgenic alopecia is inherited, as there are many genetic and environmental factors involved. However, this condition usually runs in families, and if a close relative has hair loss following a specific pattern, it is a risk factor for developing the disease.
In scarring alopecia, hair usually starts to fall out from the center of the scalp. The hair loss gradually spreads from this point. People with this type of alopecia often notice that their hair becomes brittle and breaks more easily. Other symptoms include itching, pain, or tenderness on the scalp, or redness in the affected areas.
Scarring is typically caused by inflammation, which results in the destruction of the hair follicle and irreversible hair loss. Inflammatory signs may not always be present, or the skin in these areas may appear red, flaky, have increased or decreased pigmentation, or show signs of pus inflammation. Early treatment is essential, and treatment is specific depending on the diagnosis.
Primary scarring alopecia is associated with inflammatory or autoimmune processes, in which the immune system directly attacks and destroys hair follicles.
Secondary scarring alopecia occurs as a side effect of skin trauma or damage. Hair loss in this case may be caused by burns, infections, radiation therapy, or tumors.
A doctor will examine your medical history, inspect your scalp, and often take a scalp biopsy from the edge of the hair loss area to diagnose scarring alopecia. Doctors may also take a skin swab to rule out scalp infections.
Recent studies have shown that changes in the PADI2 gene and other gene mutations are associated with scarring alopecia.
Inflammation is a major factor in the development of scarring alopecia.
It is thought that scarring alopecia can develop as a result of various factors, including:
It is caused by disrupted proportions between the growth and shedding phases β a shortened growth phase and prolonged shedding phase, or prolonged growth followed by a sudden start of multiple hairs shedding together, among other variations. Most body hair actively grows (anagen phase), but some are in the resting phase (telogen phase).
The hair growth phase lasts from 2 to 4 years, after which the hair follicle enters the resting phase. The resting phase lasts 2 to 4 months, and then the hair falls out and is replaced by new growing hair.
This type of hair loss is often temporary, and it can be triggered by various factors: stress, hormonal changes, illnesses, or medications.
There are several common causes, but in approximately 30% of cases, no specific cause can be found. Possible causes include:
Hair does not usually fall out immediately, but rather 2 to 4 months after the triggering event.
Each hair that enters the resting phase is replaced with new growing hair β not all hairs will fall out.
Sometimes the condition lasts longer and becomes chronic telogen effluvium, which may persist for several years. However, the person does not lose all their hair, and the condition often stabilizes.
In the case of telogen effluvium, hair cannot regrow because hair follicles are damaged, but there are ways to slow down and potentially stop further hair loss. Doctors usually prescribe topical or injectable corticosteroids to help suppress inflammation. Other treatment options include tetracycline (an antibiotic), cyclosporine (a medication that slows down the immune system's attack on hair follicles), or hydroxychloroquine (anti-inflammatory drugs that also help suppress the immune system).