Androgenetic Alopecia

Androgenetic alopecia (or androgenic alopecia) is the most common type of baldness in both men and women. It is caused by increased susceptibility to the action of androgen hormones, which lead to miniaturization of hair follicles and weakening of the hair shaft. It is characterized by a progressive and diffuse loss of hair, which may eventually disappear completely.

According to the Norwood–Hamilton scale, androgenetic alopecia presents in seven stages:

• Stage I: hair weakening and imperceptible shedding.
• Stage II: hair loss begins to become noticeable at the front of the head, commonly known as a receding hairline.
• Stage III: this is the threshold stage in which hair loss is not yet visually apparent. Hair loss begins at the crown, but is barely noticeable.
• Stage IV: areas without hair increase at the front and crown, although a band of hair remains between them.
• Stage V: advanced baldness. Hairless areas at the front and crown are wider, with only minimal hair remaining between them, and existing hair is weak and sparse.
• Stage VI: the frontal bald areas merge, leaving a horseshoe-shaped band of hair connecting both temples around the back of the head.
• Stage VII: the most advanced stage. Complete loss of hair on the top of the head, with hair only remaining on the sides and posterior region.

Androgenetic alopecia is a chronic and progressive condition that begins after puberty and usually stabilizes between the ages of 40 and 50 in men, and around 50 to 60 in women. With appropriate treatment, the prognosis is good, as it is possible to slow progression and even recover hair density.

Symptoms

The characteristic symptoms of androgenetic alopecia include:

• Miniaturization of hair follicles, leading to a reduction in hair shaft diameter; the hair becomes thinner.
• Noticeable hair shedding when combing, moving vigorously, or upon waking, for example.
• Decreased hair density.
• Increased sebum production on the scalp.
• In some cases, scalp redness and itching.

It is recommended to consult a specialist when more than 100 hairs are lost per day.

Causes

The main causes of androgenetic alopecia are:

• Genetic predisposition: the patient’s genetic factors (which may be inherited from either the mother or the father, although paternal influence is more significant) increase the sensitivity of hair follicles to dihydrotestosterone (DHT), a hormone derived from testosterone that plays an important role in the development of facial hair, deep voice, and male muscle mass. When DHT binds to the follicle, the hair growth phase (anagen) shortens while the resting phase (telogen) is prolonged. As a result, hair becomes thinner and, in most cases, sheds. In some cases, the hair follicle is completely lost.
• Hormonal alterations: excess DHT or hormonal imbalances during puberty or menopause may promote androgenetic hair loss.

Risk factors

The risk of androgenetic alopecia increases with the following factors:

• Sex: although it occurs in both sexes, it is more common in men. It is estimated that 60% of men and 25% of women will experience this type of alopecia during their lifetime.
• Age: although early manifestations occur at younger ages, aging makes hair follicles more susceptible to hormonal changes and reduces their regenerative capacity.

Additionally, androgenetic alopecia may worsen under the following circumstances:

• Stress: the hair growth cycle is altered, accelerating shedding.
• Nutritional deficiencies: deficiencies in vitamin B, zinc, iron, and protein weaken the hair.
• Unhealthy lifestyle habits: scalp damage may result from smoking, excessive alcohol consumption, or poor hair hygiene.
• Environmental factors: hair may be damaged by sun exposure, pollution, or excessive use of heat and chemical products.
• Hormonal disorders: hypothyroidism, hyperthyroidism, or polycystic ovary syndrome, among others, may contribute to hair loss.
• Certain medications: some drugs, such as steroids or antidepressants, affect hair health.

Complications

Androgenetic alopecia may lead to the following complications:

• Anxiety.
• Depression.
• Low self-esteem.
• Social isolation.
• Increased risk of skin cancer due to greater scalp exposure to sunlight.
• Predisposition to seborrheic dermatitis, acne, and other dermatological conditions (due to shared hormonal factors).

Prevention

Androgenetic alopecia cannot be prevented due to its genetic and hormonal basis. However, hair quality can be improved by adopting healthy lifestyle habits:

• A varied diet rich in vitamins, minerals, and proteins.
• Avoid tight hairstyles.
• Do not overuse heat styling tools for drying or styling hair.
• Reduce the use of chemical agents on hair, such as dyes, straightening, or perm products.
• Use a mild shampoo to remove excess oil and dirt.
• Reduce stress.
• Protect hair from sun exposure.
• Do not smoke.
• Avoid alcohol consumption.

Which specialist treats Androgenetic Alopecia?

Androgenetic alopecia is typically managed within the specialty of Medical-surgical dermatology and Venereology. In cases involving hormonal imbalances, an Endocrinology and Nutrition specialist may also be involved.