Definition

Alopecia is characterized by hair loss, regardless of the underlying cause. This hair loss can occur on any part of the body where hair grows, not just the scalp. Alopecia is categorized into two main types, scarring and non-scarring, with non-scarring alopecia being more common.

Causes

Hair undergoes a life cycle consisting of three phases: anagen (growth), catagen (resting), and telogen (shedding). Approximately 90% of hair is in the anagen and catagen phases at any given time.

The causes of alopecia vary depending on the type. Non-scarring alopecia is classified into 6 types:

• Alopecia Areata: This type of hair loss can occur on the scalp, face, or any part of the body. If hair loss is confined to one area, it is called alopecia areata. If it affects an entire limb, it is known as alopecia totalis, while hair loss across the entire body is referred to as universal alopecia. The exact cause is unknown, but it is believed to be linked to an autoimmune disorder where the immune system mistakenly attacks the body's own cells.
• Androgenetic Alopecia: Influenced by genetics and androgen hormones, this type of hair loss is common.
• Telogen Effluvium: This occurs when the hair cycle shifts directly from the anagen phase to the telogen phase. It can be triggered by conditions like hyperthyroidism, stress (e.g., surgery), certain medications, or nutritional deficiencies.
• Traumatic Alopecia: Caused by tight hair pulling, often seen in children. It can also result from trichotillomania, a condition where a person repeatedly pulls out their hair.
• Tinea Capitis: A fungal infection of the scalp, particularly the black dot type, can cause non-scarring alopecia.
• Anagen Effluvium: Hair loss occurring during the anagen phase, commonly seen in cancer patients undergoing chemotherapy.

Meanwhile, scarring alopecia is classified into 3 types:

• Tinea Capitis: When accompanied by inflammation, this can leave scars on the scalp.
• Mucinous Alopecia: Involves the accumulation of mucinous substances in hair follicles and oil glands, leading to inflammation that can hinder hair growth.
• Neoplastic Alopecia: Hair loss due to malignant cells attacking hair on the scalp.

Risk factor

The risk factors for alopecia depend on its type. Alopecia areata can affect individuals of any age, race, or gender, with no specific predisposition. Meanwhile, androgenetic alopecia affects 50% of men and 15% of women, particularly post-menopausal women. It is more prevalent in white people than in black people. In telogen effluvium, it is more common in women than men. For tinea capitis, it most frequently occurs in dark-skinned children. Anagen effluvium is common in cancer patients receiving chemotherapy.

Symptoms

The presentation of alopecia varies depending on its type, making a comprehensive history crucial for accurate diagnosis. Alopecia areata is typically asymptomatic, but some patients may experience a burning or itching sensation in the affected area. Alopecia areata often appears suddenly and unexpectedly, with hair loss sometimes occurring overnight.

Androgenetic alopecia develops gradually. Patients often report thinning hair, particularly on the sides and front of the head, leading to a reshaping of the hairline. In women, baldness is more commonly seen on the crown of the head.

Scarring alopecia can produce bald plaques similar to alopecia areata, but with rougher edges. The affected areas may also appear smooth and clean or exhibit redness, scaling, discoloration, or blisters filled with fluid or pus.

Diagnosis

The diagnosis of alopecia is based on a detailed medical history and physical examination. Your doctor may inquire about the pattern and sequence of your hair loss, your overall health, diet, habits (such as the use of shampoos and conditioners), and any psychological stress you may be experiencing, as stress can contribute to hair loss. A family history of alopecia may also be explored, particularly if androgenetic alopecia is suspected.

A physical examination of the scalp may involve gently pulling hair in different areas to assess hair loss. If a fungal infection is suspected, a special lamp (Wood's lamp) may be used to examine the bald area, where color differences could indicate a fungal cause.

Laboratory tests might be conducted to determine the type and cause of alopecia. These tests could include a complete blood count, assessments of iron levels, thyroid hormone function, autoimmune antibodies, testosterone, estrogen, and other reproductive hormones. To identify fungal involvement, a scalp scraping may be examined under a microscope using a KOH preparation.

Imaging tests, such as chest X-rays or MRI, may be used to evaluate mucinous alopecia. A trichoscopy, which involves using a magnifying glass to observe hair follicles, may also be performed.

Management

The treatment of alopecia varies depending on the type and underlying cause. In androgenetic alopecia, treatment may involve medications that extend the anagen (growth) phase of hair. Other medications commonly used for benign prostatic enlargement might be prescribed for men, though these are not suitable for women due to potential risks to a fetus.

Meanwhile, in alopecia areata, therapy is often not required. However, since this condition is believed to be autoimmune in nature, treatments aim to suppress the immune response. Medications can be applied topically to the scalp

For fungal alopecia (tinea capitis), antifungal medications are prescribed to eradicate the infection.

In scarring alopecia, this type necessitates more aggressive treatment due to the risk of permanent hair loss. Treatment may include anti-inflammatory medications applied to the scalp, antimalarial drugs, or isotretinoin. If hair loss stabilizes, surgical options, such as the removal of bald areas or hair follicle transplants from healthy areas, may be considered.

Complications

People with alopecia may face psychosocial complications such as anxiety and depression due to hair loss. Additionally, those with alopecia might need to undergo various examinations to check for autoimmune diseases, including Graves' disease (a thyroid condition), vitiligo (a condition causing patches of lighter skin), and others.

Prevention

Preventing alopecia depends largely on its underlying cause. Prevention of alopecia areata is challenging because it often appears suddenly and unpredictably. However, prevention of fungal alopecia can be more straightforward and includes the following measures:

• Avoid sharing combs, clothes, and towels.
• Shampoo regularly.
• Wash hands frequently.
• Avoid contact with furry animals that have bald patches on their bodies, or ensure the animal is treated before handling if it is a pet.

When to see a Doctor?

If you experience sudden hair loss, it's important to consult a doctor. Alopecia can have many causes, so a thorough examination is necessary to determine the underlying issue. While alopecia may seem harmless, it can sometimes be an indication of a more severe autoimmune disease, which requires prompt medical attention.

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