Localized acquired hypertrichosis is a condition characterized by excessive hair growth in a localized area of the body. This condition can occur on any part of the body, but is most commonly found on the face, neck, and upper extremities. The hair growth can be thick and pigmented, and may resemble the hair found on the scalp.

The exact cause of localized acquired hypertrichosis is not well understood, but there are several factors that are thought to contribute to its development. These include hormonal imbalances, medications, and underlying medical conditions. Hormonal imbalances, such as those that occur during puberty or menopause, can lead to an increase in androgen levels, which can stimulate hair growth. Certain medications, such as minoxidil, a medication used to treat hair loss, can also cause localized hypertrichosis as a side effect.

Causes

Hypertrichosis is a medical condition characterized by excessive hair growth in areas where hair is normally not present or minimal. Localized acquired hypertrichosis (LAH) refers to excessive hair growth in a localized area, and can affect any part of the body. The causes of LAH can be classified into several categories, including genetic, hormonal, metabolic, infectious, and iatrogenic.

1. Genetic Causes:

In some cases, LAH can be inherited as a result of a genetic mutation. Familial hypertrichosis is a rare genetic condition that causes excessive hair growth on the face, neck, and other parts of the body. This condition is inherited in an autosomal dominant manner, meaning that a person only needs to inherit one copy of the mutated gene from one parent to develop the condition.

2. Hormonal Causes:

Hormonal imbalances can also cause LAH. For example, an increase in androgens, male hormones, can lead to excessive hair growth in women. This can be seen in conditions such as polycystic ovary syndrome (PCOS), which is characterized by an overproduction of androgens. Hormonal imbalances can also occur as a result of certain medications, such as testosterone replacement therapy or anabolic steroids.

3. Metabolic Causes:

Metabolic disorders can also cause LAH. For example, insulin resistance, which is a hallmark of type 2 diabetes, can lead to an increase in androgen production, causing excessive hair growth. Other metabolic conditions, such as hypothyroidism, can also lead to hormonal imbalances and LAH.

4. Infectious Causes:

Infections can also cause LAH. For example, fungal infections, such as tinea corporis, can lead to the development of ringworm, which can cause hair to grow excessively in a localized area. Bacterial infections, such as folliculitis, can also cause hair to grow excessively in a localized area.

5. Iatrogenic Causes:

Iatrogenic causes refer to LAH that is caused by medical treatments or procedures. For example, radiation therapy can cause hair to grow excessively in the area that was treated. Certain medications, such as minoxidil, can also cause LAH as a side effect. In addition, cosmetic procedures, such as hair transplantation, can also lead to LAH if the transplanted hair follicles become overactive.

Symptoms

The following are the main symptoms of localized acquired hypertrichosis:

1. Excessive hair growth: This is the most obvious symptom of localized acquired hypertrichosis, and it is characterized by an increase in the amount of hair in the affected area. The hair can be dark, long, and dense, and can grow to lengths much longer than the surrounding hair.
2. Rapid hair growth: The hair growth in localized acquired hypertrichosis is often rapid, and can occur over a relatively short period of time. In some cases, the hair growth can occur so rapidly that it is noticeable within a few days or weeks.
3. Hirsutism: Hirsutism is a condition characterized by the growth of hair in areas of the body where it is typically not seen, such as the face, neck, chest, and back. In people with localized acquired hypertrichosis, hirsutism can be a prominent symptom.
4. Coarse hair: The hair that grows in localized acquired hypertrichosis is often coarse and thick, and may have a different texture than the surrounding hair.
5. Itching and irritation: In some cases, the excessive hair growth in localized acquired hypertrichosis can cause itching and irritation, particularly if the hair rubs against clothing or other surfaces.
6. Inflammation and redness: In some cases, the skin in the affected area can become inflamed and red, and may develop a rash or other skin irritation.
7. Pain or discomfort: In some cases, the excessive hair growth in localized acquired hypertrichosis can cause pain or discomfort, particularly if the hair is pulled or if it rubs against clothing or other surfaces.
8. Psychological distress: The excessive hair growth in localized acquired hypertrichosis can cause significant psychological distress, particularly in people who are self-conscious about their appearance. In some cases, the condition can lead to depression, anxiety, and low self-esteem.

It is important to note that the symptoms of localized acquired hypertrichosis can vary greatly from person to person, and the severity of the symptoms can also vary. Some people may have mild symptoms that are easily managed, while others may experience more severe symptoms that have a significant impact on their quality of life.

Diagnosis

Diagnosis of Localized Acquired Hypertrichosis:

1. Clinical examination: A thorough physical examination is the first step in the diagnosis of localized acquired hypertrichosis. During the examination, the dermatologist will look for any signs of hair growth in a localized area of the body, such as the face, neck, or arms. They will also examine the texture and color of the hair to determine if it is similar to normal hair or if it is coarser and darker.
2. Medical history: The dermatologist will also ask the patient about their medical history, including any previous illnesses or treatments, to determine if there is any underlying medical condition that may be causing the hair growth.
3. Skin biopsy: In some cases, a skin biopsy may be necessary to confirm the diagnosis of localized acquired hypertrichosis. During the biopsy, a small piece of skin is removed and examined under a microscope to look for any abnormal hair follicles or other signs of abnormal hair growth.

Diagnostic Tests for Localized Acquired Hypertrichosis:

1. Hormonal tests: Hormonal tests may be performed to determine if an underlying hormonal imbalance is causing the hair growth. These tests may include blood tests to measure levels of hormones such as testosterone, cortisol, and DHEA.
2. Thyroid function tests: Thyroid function tests may be performed to determine if an underlying thyroid disorder is causing the hair growth. These tests measure the levels of thyroid hormones in the blood and determine if the thyroid gland is functioning normally.
3. Blood tests for autoimmune disorders: Blood tests may be performed to determine if an autoimmune disorder is causing the hair growth. These tests measure the levels of antibodies in the blood and determine if the body is producing an abnormal immune response.
4. Imaging studies: Imaging studies such as CT scans, MRI scans, or ultrasound may be performed to determine if there is any underlying structural abnormality causing the hair growth. These studies can also help to identify any masses or tumors that may be causing the hair growth.
5. Dermatoscopy: Dermatoscopy is a non-invasive diagnostic tool that uses a special magnifying lens to examine the hair and skin. It can be used to determine if the hair growth is due to an underlying skin condition or if it is due to an abnormality in the hair follicles.
6. Trichogram: A trichogram is a diagnostic test that involves the examination of individual hair follicles to determine if there is any abnormality in their growth or structure. This test can help to determine if the hair growth is due to an underlying hair disorder or if it is due to an abnormality in the hair follicles.

Treatment

The treatment of localized acquired hypertrichosis depends on the underlying cause and the severity of the condition.

Here is a list of the main treatments for localized acquired hypertrichosis:

1. Topical medications: Topical medications, such as minoxidil, can be effective in reducing excessive hair growth in some cases. Minoxidil works by increasing blood flow to the hair follicles, which can stimulate hair growth.
2. Hormonal therapy: Hormonal imbalances, such as an overproduction of androgens, can be a cause of localized acquired hypertrichosis. In such cases, hormonal therapy, such as oral contraceptives or anti-androgens, can be used to regulate the levels of hormones in the body and reduce excessive hair growth.
3. Laser hair removal: Laser hair removal is a non-invasive procedure that uses laser energy to destroy hair follicles and prevent future hair growth. This treatment is effective for reducing hair growth in small, localized areas and can provide long-lasting results.
4. Electrolysis: Electrolysis is a method of hair removal that uses a small electric current to destroy hair follicles. This treatment is effective for reducing hair growth in small, localized areas and can provide long-lasting results.
5. Shaving or trimming: For some individuals, simply shaving or trimming the affected area may be sufficient to manage localized acquired hypertrichosis. This method is non-invasive and does not require any special equipment or training.
6. Waxing or plucking: Waxing or plucking the affected area can also be effective in reducing excessive hair growth. These methods are non-invasive and can be performed at home or in a salon.
7. Depilation creams: Depilation creams can be used to dissolve hair at the surface of the skin, making it easier to remove. This method is non-invasive and can provide temporary relief from excessive hair growth.
8. Surgical removal: In some cases, surgical removal of the affected area may be necessary to manage localized acquired hypertrichosis. This option is typically reserved for severe cases or when other treatments have been ineffective.

It is important to note that the most effective treatment for localized acquired hypertrichosis will depend on the underlying cause of the condition and the individual’s unique circumstances. It is recommended that individuals with this condition speak with a healthcare provider to determine the most appropriate treatment plan for their needs.