Pterygium Inversus Unguis is a medical condition characterized by an abnormal growth of the nail matrix, which results in the formation of a triangular or wing-shaped projection under the nail plate. It affects the toenails and fingernails, and can cause pain, discomfort, and deformity of the nails.

There are two main types of Pterygium Inversus Unguis: congenital and acquired.

Congenital Pterygium Inversus Unguis is a rare condition that is present at birth. It is caused by a genetic mutation that affects the development of the nail matrix. This type of pterygium is typically more severe and can result in multiple deformities of the nails, including nail dystrophy, onychogryphosis (nail thickening), and onychauxis (nail hypertrophy). In some cases, the nails may be absent altogether.

Acquired Pterygium Inversus Unguis, on the other hand, is a condition that develops later in life, usually as a result of trauma, infection, or a medical condition such as psoriasis. This type of pterygium is typically less severe than the congenital form and may only affect one nail.

Both congenital and acquired Pterygium Inversus Unguis can cause pain and discomfort, as well as cosmetic concerns. In severe cases, the pterygium can interfere with the normal function of the nail and surrounding tissue, leading to difficulty with activities such as walking, wearing shoes, or performing manual tasks.

Causes

There are several factors that can contribute to the development of pterygium inversus unguis, including genetic predisposition, trauma, underlying medical conditions, and environmental factors.

1. Genetics – Pterygium inversus unguis has a strong genetic component, and the condition is often inherited in an autosomal dominant manner. This means that if a parent has the condition, there is a 50% chance that each of their children will also have the condition. Researchers have identified several genetic mutations that can lead to pterygium inversus unguis, including mutations in the HOXD13 gene. This gene plays a role in the development of the fingers and toes, and mutations in this gene can lead to abnormal growth and development of the nails.

2. Trauma – Trauma to the digit can also lead to the development of pterygium inversus unguis. This can occur as a result of direct injury to the digit or due to repeated microtrauma to the digit over time. In some cases, trauma can cause the nail matrix to become damaged, leading to abnormal nail growth. Additionally, repeated trauma to the digit can cause inflammation and swelling, which can further contribute to the development of pterygium inversus unguis.

3. Underlying medical conditions – Several underlying medical conditions can also contribute to the development of pterygium inversus unguis. For example, conditions such as psoriasis, eczema, and lichen planus can cause inflammation and irritation of the skin, leading to abnormal nail growth. Additionally, certain medical conditions, such as congenital syphilis, can cause abnormal growth and development of the nails.

4. Environmental factors – Certain environmental factors can also contribute to the development of pterygium inversus unguis. For example, exposure to toxic chemicals and pollutants, such as solvents and heavy metals, can cause damage to the nail matrix and lead to abnormal nail growth. Additionally, frequent exposure to moisture and water can cause the skin and nails to become softened, making them more susceptible to trauma and abnormal growth.
5. Aging: As people age, their nails become less flexible and more brittle, which can lead to the development of pterygium inversum unguis. This may be due to a decrease in the production of keratin, the protein that makes up the nails, as well as a decrease in circulation to the nails.
6. Trauma: Trauma to the nails, such as repeated nail biting or picking, can cause the nails to become brittle and develop ridges or grooves.
7. Chronic diseases: Chronic diseases, such as diabetes and thyroid disorders, can affect the health of the nails and lead to the development of pterygium inversum unguis.
8. Certain medications: Certain medications, such as chemotherapy drugs and retinoids, can cause changes in the nails that lead to pterygium inversum unguis.
9. Vitamin and mineral deficiencies: A lack of certain vitamins and minerals, such as biotin and iron, can affect the health of the nails and lead to the development of pterygium inversum unguis.

The symptoms of pterygium inversum unguis are relatively mild and typically include brittle, thin, and ridged or grooved nails. In some cases, the nails may become discolored, and the skin around the nails may become red and inflamed. The condition is usually not painful, but it can be unsightly and can make it difficult to wear gloves or shoes.

Symptoms

The main symptoms of Pterygium Inversus Unguis include:

1. Nail grooves or furrows: The most prominent symptom of this condition is the inward growth of the nail into the surrounding tissue, resulting in a deep groove or furrow on the nail plate. This can cause the nail to become distorted and misshapen, leading to difficulties with activities of daily living.
2. Pain and discomfort: As the nail continues to grow into the surrounding tissue, it can cause pain and discomfort in the affected area. This can be particularly pronounced when wearing shoes or engaging in activities that put pressure on the affected nail.
3. Nail separation: In some cases, the nail may separate from the nail bed, causing further pain and discomfort. This can also result in an increased risk of infection in the affected area.
4. Inflammation and redness: As the nail continues to grow into the surrounding tissue, it can cause inflammation and redness in the affected area. This can be accompanied by swelling and tenderness, and in some cases, may also cause a discharge or fluid buildup.
5. Deformed nails: Pterygium Inversus Unguis can cause the nails to become deformed and misshapen, with the nail plate appearing to be curved or twisted. This can make it difficult to perform activities of daily living, such as writing or typing, and can also cause difficulties with walking or wearing shoes.
6. Difficulty with activities of daily living: Due to the deformity of the nail and the pain and discomfort associated with the condition, individuals with Pterygium Inversus Unguis may experience difficulties with activities of daily living, such as writing, typing, or walking.

Diagnosis

Diagnosis of PIU typically involves a physical examination of the affected nails and a review of the patient’s medical history. The following tests may also be used to diagnose and evaluate the severity of PIU:

1. Physical examination: A physical examination is the first step in diagnosing pterygium inversus unguis. During this examination, the doctor will look for signs of an inward-facing groove or furrow on the affected nail, as well as any redness, swelling, or pain in the surrounding area.
2. Nail Clippings Test: Nail clippings from the affected nail are taken and examined under a microscope to look for any structural abnormalities in the nail matrix (the part of the nail bed where the nail is formed).
3. Nail Biopsy: A small sample of the nail and nail bed is taken for analysis to rule out any underlying medical conditions that may be contributing to the nail abnormality.
4. Dermatological Tests: A skin biopsy or other dermatological tests may be performed to rule out any skin conditions that may be contributing to the nail abnormality.
5. Family History: A review of the patient’s family medical history may be performed to determine if there is a genetic component to the condition.
6. Radiographs: X-rays can be used to get a clear image of the affected area and to look for any underlying conditions that may be contributing to the pterygium inversus unguis.
7. Biopsy: In some cases, a biopsy may be performed to obtain a sample of the affected tissue for laboratory analysis. This can help to confirm the diagnosis and rule out other conditions that may be causing the symptoms.
8. Culture: A culture can be performed to determine if there is an infection present in the affected area. This can be done by obtaining a sample of the fluid or tissue from the affected area and growing it in a laboratory to identify the type of bacteria or fungus that may be causing the infection.
9. Blood tests: Blood tests may be performed to check for underlying medical conditions that may be contributing to the pterygium inversus unguis, such as diabetes or an autoimmune disease.
10. Magnetic resonance imaging (MRI): An MRI can be used to get a detailed image of the affected area and to look for any underlying conditions that may be contributing to the pterygium inversus unguis.

It is important to note that not all of these tests may be necessary in every case, and the specific tests that are performed will depend on the individual case and the doctor’s assessment of the patient’s symptoms and medical history.

Treatment

Non Pharmacological

There are several treatments available for pterygium inversum unguis, including surgical and non-surgical options. The choice of treatment depends on the severity of the condition and the individual patient’s preferences. Here are some of the main treatments for pterygium inversum unguis:

1. Observation and nail care: In some cases, pterygium inversum unguis may not cause any symptoms or functional limitations. In these cases, observation and proper nail care may be sufficient to manage the condition. This can include avoiding injury to the affected nail, keeping the nail trimmed, and using a soft-bristled brush to gently clean the affected area.
2. Nail bracing: Nail bracing is a non-surgical treatment that involves the use of a custom-made device to help straighten the affected nail. The device is made of a flexible material and fits over the affected nail, holding it in place and helping to prevent further inward growth. Nail bracing is typically worn for several months and can be adjusted as needed to accommodate changes in the nail.
3. Nail surgery: Surgical treatment for pterygium inversum unguis involves removing the affected portion of the nail and surrounding tissue. This can be done under local or general anesthesia and typically requires a few weeks of post-operative recovery. The surgical procedure can be performed using a variety of techniques, including excision, avulsion, and matrixectomy.
4. Matrixectomy: Matrixectomy is a surgical procedure that involves removing the matrix, or the area of the nail bed responsible for producing the nail. This is typically done in cases of severe pterygium inversum unguis, where the inward growth of the nail has caused significant deformity and functional limitations. After the matrix is removed, the affected nail will no longer grow, and a new nail may eventually form in its place.
5. Avulsion: Avulsion is a surgical procedure that involves removing the entire nail plate, along with the affected portion of the matrix. This is typically done in cases of severe pterygium inversum unguis, where the inward growth of the nail has caused significant deformity and functional limitations. After the avulsion, the affected nail will no longer grow, and a new nail may eventually form in its place.
6. Excision: Excision is a surgical procedure that involves removing the affected portion of the nail plate and surrounding tissue. This is typically done in cases of mild to moderate pterygium inversum unguis, where the inward growth of the nail has caused only minor deformity. After the excision, the nail will continue to grow normally, and no further surgical intervention should be necessary.
7. Physical therapy: Physical therapy, such as splinting or taping, may be recommended to improve nail appearance and prevent further deformity.

Medications

There are several medical and surgical options available for treating PIU, including:

1. Topical corticosteroids: Topical corticosteroids, such as clobetasol propionate, can be used to reduce inflammation and relieve pain. The corticosteroids are applied directly to the affected nail and surrounding skin.
2. Systemic corticosteroids: In cases of severe pain or inflammation, systemic corticosteroids may be prescribed. These medications are taken orally and work by reducing inflammation throughout the body.
3. Antifungal agents: Antifungal agents, such as terbinafine or itraconazole, may be prescribed if a fungal infection is present. These medications can help to improve nail appearance and reduce symptoms.
4. Pain relievers: Over-the-counter pain relievers, such as acetaminophen or ibuprofen, may be recommended to relieve pain and discomfort associated with PIU.
5. Nail debridement: Nail debridement is a procedure in which the affected nail is trimmed or filed down to reduce pain and improve appearance. This procedure may be performed by a healthcare provider or at home with proper instruction.
6. Nail avulsion: Nail avulsion is a surgical procedure in which the affected nail is completely removed. This procedure may be recommended if the nail is causing significant pain or if other treatments have been unsuccessful.
7. Nail matrix excision: Nail matrix excision is a surgical procedure in which the portion of the nail matrix responsible for the inward growth of the nail is removed. This procedure can help to prevent further deformity and improve nail appearance.
8. Nail reconstruction: Nail reconstruction is a surgical procedure in which a new nail is created using skin or other materials. This procedure is typically performed after nail avulsion or matrix excision and can help to restore normal nail appearance and function.
9. Injection therapy: Injection therapy is a non-surgical treatment that involves injecting a medication into the affected area to help straighten the nail. This can be done using a variety of medications, including corticosteroids, which are anti-inflammatory drugs that can help reduce swelling and pain. Injection therapy is typically used in cases of mild to moderate pterygium inversum unguis and may be performed in conjunction with other treatments