Alopecia

Alopecia, or baldness, is the abnormal loss of hair in both men and women. This condition occurs most commonly on the scalp, but it can also affect other parts of the body, such as the eyebrows, eyelashes, armpits, beard, or genital area.

Hair loss is a normal part of the hair growth cycle; generally, between 50 and 100 hairs fall out daily and are replaced by new ones that grow from hair follicles. This loss is considered pathological when a greater amount of hair is shed or when the loss is normal but the hair is not replaced.

Depending on its characteristics, there are several different types of baldness:

• Non-scarring alopecia: The hair follicles are damaged but not destroyed, making it potentially reversible.
• Androgenic alopecia or common baldness: Develops gradually, beginning with hair thinning and ending with the complete destruction of the hair bulb, preventing new hair growth.
• Male androgenic alopecia: The most common type, characterized by decreased hair density and a distinctive pattern (loss of hair on the top of the head while maintaining it on the sides).
• Female androgenic alopecia: Characterized by thinning and the appearance of sparse areas, usually on the top of the head.
• Diffuse alopecia: Manifests in a generalized way, with hair falling out evenly across all scalp areas.
• Alopecia areata: A focal alopecia limited to a specific area of the scalp.
• Traumatic alopecia: Results from scalp injuries caused by the patient’s own behavior.
• Telogen effluvium: Temporary but very noticeable hair loss, with clumps of hair falling out suddenly. Over time, hair regrows naturally or with specific treatment.
• Scarring alopecia: The hair follicles are destroyed and replaced by fibrous scar tissue. It is a rare condition and can be irreversible.

The prognosis of baldness varies depending on its causes. Scarring alopecia tends to be permanent, while non-scarring alopecia is often reversible.

Symptoms

Symptoms vary depending on the type of alopecia. The most common include:

• Androgenic alopecia: Hair becomes finer and is lost gradually, usually from the frontal and top areas of the scalp.
• Diffuse alopecia: Generalized hair loss across all scalp areas.
• Alopecia areata: Round patches without hair form, which can progress to total hair loss.
• Traumatic alopecia: Hair loss starts on the sides, behind the ears, and on the crown. The scalp may show mild inflammation and become more sensitive, with itching and headaches.
• Telogen effluvium: Significant, sudden hair loss, even in clumps, causing a reduction in volume and visible scalp.
• Scarring alopecia due to lichen planus: Red bumps form on the scalp, causing itching and gradual hair loss.
• Frontal fibrosing alopecia: Affects only the front part of the scalp, causing hairline recession and eyebrow loss.

Causes

The causes of alopecia are highly varied:

• Non-scarring alopecia:
• Androgenic alopecia: Caused by genetic and hormonal factors that increase sensitivity to androgens. Dihydrotestosterone (DHT) reduces the size of hair follicles and increases sebum production, making hair weaker and eventually halting growth.
• Diffuse alopecia: Usually caused by endocrine disorders, hormonal imbalances, medications, or nutritional deficiencies.
• Alopecia areata: An autoimmune disease in which the body attacks its own hair follicles.
• Traumatic alopecia: Caused by poor hairstyling habits or psychological conditions such as stress or trichotillomania (the compulsion to pull out one’s own hair).
• Telogen effluvium: A disruption of the hair growth cycle caused by hormonal changes, stress, nutritional deficiencies, certain medications, or infections.
• Scarring alopecia: May result from three main causes:
• Primary alopecia: Hair follicles are damaged or lost due to developmental abnormalities or hereditary causes.
• Acquired alopecia: Occurs as a result of certain skin conditions:
• Lichen planopilaris: An autoimmune disease that destroys hair follicles.
• Frontal fibrosing alopecia: Hair follicles at the front of the scalp are destroyed by the immune system for unknown reasons.
• Graham-Little syndrome: A skin condition characterized by progressive scarring on the scalp.
• Secondary alopecia: Hair follicles are damaged by infection, diseases such as ringworm or cancerous tumors, burns, or medical treatments such as radiotherapy.

Risk Factors

Factors that increase the risk of alopecia include:

• Family history.
• Physical and psychological stress.
• Lupus.
• Diabetes.
• Radiotherapy.
• Chemotherapy.
• Nutritional deficiencies (iron, zinc, biotin, vitamin D, vitamin B12, protein).
• Hormonal changes or imbalances (pregnancy, menopause, polycystic ovary syndrome, hypothyroidism).
• Fungal infections, especially tinea capitis.
• Medications: certain anti-inflammatory drugs, antidepressants, anticoagulants, or antibiotics.
• Eating disorders.

Complications

The most frequent complications of baldness include:

• Increased skin exposure to sunlight.
• Scalp hypersensitivity.
• Personality changes.
• Low self-esteem.
• Social isolation.
• Depression.
• Anxiety.

Prevention

In most cases, alopecia cannot be prevented. To maintain healthy hair, it is recommended to handle it gently, avoid excessive heat, refrain from tight hairstyles, and protect it from sunlight.

Which doctor treats alopecia?

Specialists in medical-surgical dermatology and venereology are responsible for diagnosing and treating alopecia.