Localized Congenital Hypertrichosis

Localized congenital hypertrichosis (LCH) is a rare condition characterized by excessive hair growth in one or more localized areas of the body. This condition can affect people of all ages and both sexes, but it is most commonly seen in infants and young children


The exact causes of LCH are still not well understood, but several factors have been suggested to play a role in its development.

  1. Genetics:

One of the main causes of LCH is believed to be a genetic mutation that affects the hair follicle. Studies have identified several genes that are associated with the condition, including the HR gene, which is involved in the regulation of hair growth. Mutations in this gene can lead to excessive hair growth in specific areas of the body. Other genes that have been linked to LCH include the KRT75 gene, which is involved in the formation of the hair shaft, and the KRT71 gene, which regulates the size of hair follicles.

  1. Environmental factors:

Environmental factors, such as exposure to certain chemicals or toxins, may also play a role in the development of LCH. For example, exposure to certain drugs, such as minoxidil, which is used to treat hair loss, can cause excessive hair growth in some people. Additionally, exposure to certain chemicals, such as polychlorinated biphenyls (PCBs), which are found in some industrial products, has been linked to LCH.

  1. Hormonal imbalances:

Hormonal imbalances, such as an overproduction of androgens, can also cause LCH. Androgens are male hormones that are present in both men and women and play a role in regulating hair growth. An overproduction of androgens can cause excessive hair growth in specific areas of the body.

  1. Infections:

Infections, such as rubella, chickenpox, and cytomegalovirus, have been linked to LCH. These infections can cause inflammation and damage to the hair follicles, leading to excessive hair growth.

  1. Neurofibromatosis type 1:

Neurofibromatosis type 1 (NF1) is a genetic disorder that can cause LCH. NF1 is characterized by the development of tumors on the nerves and skin, as well as other symptoms, such as cafe-au-lait spots and freckling. LCH is often seen in people with NF1, although the exact relationship between the two conditions is not well understood.

  1. Nevoid basal cell carcinoma syndrome:

Nevoid basal cell carcinoma syndrome (NBCCS) is another genetic disorder that can cause LCH. NBCCS is characterized by the development of basal cell carcinomas, which are a type of skin cancer, as well as other symptoms, such as cysts and skeletal abnormalities. LCH is often seen in people with NBCCS, and it is believed that the excessive hair growth is a result of the underlying genetic mutations that cause the condition.

  1. Congenital syphilis:

Congenital syphilis is a sexually transmitted infection that can be passed from a mother to her baby during pregnancy. If a baby is born with congenital syphilis, they may develop a number of symptoms, including LCH. The excessive hair growth is believed to be a result of the inflammation and damage caused by the infection to the hair follicles.


The main symptoms of LCH include:

  1. Excessive hair growth: The most noticeable symptom of LCH is the presence of excessive hair growth in isolated areas of the body. This hair growth can be in the form of thick, dark, and long hairs and can be present on the face, neck, arms, legs, or other areas of the body.
  2. Localized patches of hair: LCH is characterized by the presence of well-defined patches of hair that are separate from the normal hair growth patterns of the rest of the body. These patches of hair may be symmetrical or asymmetrical, and can vary in size and shape.
  3. Hair growth patterns: In some cases, the hair growth patterns associated with LCH may be unusual, such as spiral or swirl patterns.
  4. Early onset: LCH is present at birth and can be diagnosed soon after birth.
  5. No other physical abnormalities: LCH is often an isolated condition, and individuals with LCH do not typically have any other physical abnormalities or medical conditions associated with it.

It is important to note that the severity of LCH can vary greatly from person to person, and some individuals may have only a few patches of hair while others may have extensive hair growth over a large portion of their body.


The following are the main diagnostic tests that are used to diagnose localized congenital hypertrichosis:

  1. Physical examination: This is the first step in diagnosing localized congenital hypertrichosis. A dermatologist or geneticist will examine the affected area of the body and look for signs of excessive hair growth. They will also take a detailed medical history, including any family history of similar conditions.
  2. Skin biopsy: A skin biopsy is a procedure in which a small sample of skin is removed and examined under a microscope. This can help to determine the type of hair follicle that is producing the excessive hair growth and can provide information about the underlying cause of the condition.
  3. Genetic testing: Genetic testing is a powerful tool for diagnosing inherited conditions, including localized congenital hypertrichosis. This may involve sequencing specific genes that are known to be associated with hair growth regulation, such as the SHH gene.
  4. Hormonal testing: Hormonal imbalances can sometimes cause excessive hair growth, so it may be necessary to perform hormonal testing to rule out any underlying hormonal disorders. This may include measuring levels of testosterone, dihydrotestosterone, and other hormones that can affect hair growth.
  5. Imaging studies: Imaging studies, such as CT scans or MRI scans, can help to rule out any underlying structural abnormalities or tumors that may be causing the excessive hair growth.
  6. Family history: A thorough family history can provide important clues about the inheritance pattern of the condition and can help to determine the likelihood of passing the condition on to future generations.

Once a diagnosis of localized congenital hypertrichosis has been made, a treatment plan can be developed. In some cases, the condition may resolve on its own over time, but in others, it may persist throughout life. In either case, treatment options may include hair removal methods, such as laser hair removal or electrolysis, or medications that can help to reduce hair growth.


There is no cure for LCH, but there are several treatments available to manage its symptoms. The main treatments for LCH are:

  1. Hair removal: Hair removal treatments, such as waxing, shaving, or electrolysis, can be used to remove the excess hair. However, these treatments are temporary and will need to be repeated regularly.
  2. Laser hair removal: Laser hair removal is a popular treatment for LCH. It works by targeting the hair follicles with intense pulses of light that destroy the hair at the root. Laser hair removal is a long-lasting treatment, but it may take several sessions to achieve the desired results.
  3. Topical medications: Topical medications, such as minoxidil, can be applied to the affected area to slow down hair growth. However, the effectiveness of these medications varies from person to person, and they may not work for everyone.
  4. Surgical options: In severe cases of LCH, surgical options may be considered. For example, a surgical procedure called electrodissection can be used to remove the hair follicles. This procedure is usually performed under local anesthesia and may leave scarring.
  5. Psychological support: People with LCH may experience psychological distress, such as anxiety and depression, as a result of their condition. Psychological support, such as counseling or therapy, can help people manage their emotions and improve their mental health.

In addition to these treatments, people with LCH may also benefit from using cosmetics and clothing to conceal their condition. For example, they may use makeup to cover the affected area or wear clothing that covers the affected area, such as long-sleeved shirts or pants.