Androgenetic alopecia: what is it, causes, treatment, prognosis

What is Androgenetic Alopecia?

Androgenetic alopecia (or androgenic alopecia) Is a common form of hair loss in both men and women. In men, the condition is also called male pattern baldness. Hair falls out in a clear pattern starting at both temples. Over time, the hairline recedes and takes on a characteristic M-shape. Hair also grows thinner at the crown (near the crown), often progressing to partial or complete baldness.

Baldness in women it differs from male pattern baldness. In women, the hair becomes thinner all over the head, and the hairline does not recede. Androgenic alopecia in women rarely leads to complete baldness.

Androgenetic alopecia in men is associated with a number of other conditions, including ischemic heart diseaseand an enlarged prostate. In addition, prostate cancer, insulin resistance (for example, diabetes and obesity) and high blood pressure (arterial hypertension

) are associated with androgenetic alopecia. In women, this form of hair loss is associated with an increased risk of polycystic ovary syndrome (PCOS). PCOS is characterized by hormonal imbalancewhich can lead to irregular periods, acne, excess hair on other parts of the body (hirsutism), and weight gain.

Causes and risk factors

Various genetic and environmental factors are likely to play a role in the onset of androgenetic alopecia. While researchers are investigating risk factors that may contribute to this condition, most of these factors remain unknown. Researchers have determined that this form of hair loss is related to hormones called androgens, specifically an androgen called dihydrotestosterone. Androgens are important for the normal sexual development of men before birth and during puberty. Androgens also perform other important functions in both men and women, such as regulating hair growth and sex drive.

Hair growth begins under the skin in structures called follicles. Each strand of hair usually grows for 2 to 6 years, enters a resting phase for several months, and then falls out. The cycle starts over when new hair begins to grow on the follicle. Increased levels of androgens in hair follicles can lead to shorter hair growth cycles and shorter, thinner strands. In addition, new hair growth is delayed to replace lost strands.

Although researchers suspect multiple genes play a role in androgenetic alopecia, scientific studies have confirmed variations in only one gene. AR. Gene AR provides instructions for making a protein called the androgen receptor. Androgen receptors allow the body to respond appropriately to DHT and other androgens. Research shows that gene mutations AR lead to increased activity of androgen receptors in hair follicles. However, it remains unclear how these genetic changes increase the risk of hair loss in men and women with androgenetic alopecia.

Researchers continue to study the link between androgenetic alopecia and other diseases, such as coronary artery disease and prostate cancer in men and polycystic ovary syndrome in women. They believe that some of these disorders may be related to elevated androgen levels, which may help explain why they tend to occur with androgen-related alopecia. Other hormonal, environmental and genetic factors that have not been identified may also be involved.

- Inheritance.

The inheritance pattern of androgenetic alopecia is unclear as many genetic and environmental factors are likely to be involved. However, the disorder tends to cluster in families, and having a close relative with androgenetic alopecia appears to be a risk factor for the condition.

Epidemiology

White patients suffer the most, followed by Asians and African Americans, followed by Native Americans and Eskimos. The incidence is approaching age in men of the Caucasian race: 50% - by 50 years and up to 80% - by 70 years. In women, this disease is quite common after menopause.

Diagnostics

Androgenetic alopecia is usually diagnosed clinically with a history of gradual onset occurring after puberty and often, but not necessarily, with a family history of baldness. A biopsy is usually not required unless a diagnosis is made. Dermatoscopy reveals miniature hair and brown perihilar casts that help distinguish alopecia areata from diffuse alopecia areata, which mimics male pattern baldness.

Careful review of the patient's medical history and medication list is important to ensure that there are no other causes of hair loss or other reasons for identifying androgenetic alopecia. Thyroid exams, complete blood counts, screening for iron deficiency, total iron binding capacity, and ferritin may be required. If you suspect syphilis. All patients with hair loss who see a dermatologist may also need a prompt psychiatric evaluation for depressive symptoms and other psychiatric disorders.

Treatment

There are two approved hair loss medications, topical minoxidil and finasteride, both of which require at least 4-6 months of use before improvement appears, and should be used indefinitely to maintain answer. Thus, adherence to treatment is often difficult. In addition, the beginning of the drug intake can trigger an initial phase of excretion. The drugs work best together.

Topical minoxidil is available over the counter in various concentrations, up to a 5% solution. The higher the strength, the more effective. The most common side effects are itchy skin and local irritation followed by flaking. The latter is usually due to the propylene glycol or alcohol in the drug. Minoxidil is a potassium channel blocker and dilates the blood vessels, which hypothetically allow more oxygen, blood and nutrients to pass to the follicles and promote the anagen phase.

Finasteride is a type 2 5-alpha reductase inhibitor, not an antiandrogen. It is given at a dose of 1 mg per day and is more effective in increasing hair growth at the crown than at the front of the scalp. The effectiveness of finasteride is unclear for female pattern baldness and is contraindicated in women with reproductive potential (category X), because it can cause an ambiguous male fetus development of the genitals. Side effects include sexual dysfunction, which usually diminishes over time; an increased risk of high-grade prostate cancer; and reports of cases of persistent decreased libido and erectile dysfunction.

Other medications used for hair loss are not approved for the treatment of androgenetic alopecia. Dutasteride is three times more effective against the type II 5-alpha reductase enzyme, 100 times more effective more effective against type 1 enzyme and is often used in patients who have not been helped finasteride. The side effect profile is similar to that of finasteride.

Oral antiandrogens such as spironolactone are often used in women. Spironolactone is a very weak partial androgen receptor agonist, blocking the much more potent dihydrotestosterone (DHT) and free testosterone from interacting with the androgen receptor, thus physiologically acting as a direct antagonist. It also inhibits androgen synthesis and increases the conversion of testosterone to estradiol. Antiandrogens are more effective if there are other signs of virilization.

Hair transplant is effective and cosmetically satisfying for the patient. However, patients must have a sufficient number of donor plugs (more than 40 follicular units / cm2) to cover the bald spot. New methods have made hair transplant more aesthetic and natural.

Other suggested treatments include saw palmetto extract; prostaglandin analogs such as latanoprost and bimatoprost, which can be prohibitively expensive.

Forecast

- Psychological.

Androgenetic alopecia is usually perceived as "a mildly stressful condition that lowers body satisfaction." However, while most men view baldness as an unwanted and excruciating experience, they are usually able to cope with it and maintain their integrity.

Although baldness in women is not as common as in men, the psychological effects of hair loss are generally much stronger. Usually, the front hairline is maintained, but hair density is reduced in all areas of the scalp. It was previously thought to be caused by testosterone, as in male pattern baldness, but most women who have hair loss have normal testosterone levels.