Idiopathic Palmoplantar Hidradenitis

Idiopathic palmoplantar hidradenitis (IPH) is a rare skin disorder that affects the palms of the hands and the soles of the feet. It is characterized by the formation of painful nodules, cysts, and abscesses in these areas, which can lead to the development of chronic wounds and scarring. The condition is considered idiopathic, meaning that its exact cause is unknown, although there are some theories that suggest it may be related to an autoimmune or inflammatory response.

IPH is typically diagnosed based on clinical presentation and histological examination of affected tissue. The primary symptom is the formation of deep-seated nodules or cysts in the palms and soles. These nodules may be tender or painful and can vary in size and number. In severe cases, they may progress to form abscesses, which can drain pus and lead to the formation of chronic wounds. The condition may be unilateral or bilateral and can affect one or both palms and soles.

There are several types of IPH, including:

1. Type 1 IPH: This is the most common form of IPH, and it typically affects young adults. The condition is characterized by the formation of multiple nodules and cysts in the palms and soles, which can be painful and may drain pus. The lesions may be symmetric or asymmetric and can affect one or both hands and feet.
2. Type 2 IPH: This form of IPH is less common and typically affects older adults. It is characterized by the formation of solitary or few nodules and cysts in the palms and soles, which are usually less painful than those seen in type 1 IPH. The lesions may be asymmetric and can affect one or both hands and feet.
3. Type 3 IPH: This is the rarest form of IPH and is typically associated with other autoimmune or inflammatory conditions, such as psoriasis, lupus, or rheumatoid arthritis. The condition is characterized by the formation of multiple nodules and cysts in the palms and soles, which are often painful and may drain pus. The lesions may be symmetric or asymmetric and can affect one or both hands and feet.

Causes

The term ‘idiopathic’ means that the cause of this condition is unknown. However, several factors have been associated with the development of IPH. In this article, we will discuss the main causes of idiopathic palmoplantar hidradenitis and explain each of them in detail.

1. Genetics: IPH is believed to have a genetic component, as it tends to run in families. However, the exact genes responsible for this condition have not been identified yet. Studies have suggested that mutations in certain genes may lead to the development of IPH, but more research is needed to confirm this.
2. Bacterial Infections: Bacterial infections have also been linked to the development of IPH. For instance, some studies have suggested that Staphylococcus aureus, a type of bacteria commonly found on the skin, may be involved in the formation of nodules or cysts on the palms and soles. However, the exact role of bacterial infections in the development of IPH is not fully understood, and more research is needed in this area.
3. Autoimmune Disorders: Autoimmune disorders, such as psoriasis, lupus, and rheumatoid arthritis, have also been linked to the development of IPH. This suggests that the immune system may play a role in the formation of nodules or cysts on the palms and soles. However, more research is needed to confirm this hypothesis.
4. Obesity: Obesity has also been identified as a risk factor for IPH. This may be because obesity is associated with a higher level of inflammation in the body, which may contribute to the formation of nodules or cysts on the palms and soles.
5. Smoking: Smoking has also been linked to the development of IPH. This may be because smoking is associated with a higher level of oxidative stress, which may contribute to the formation of nodules or cysts on the palms and soles.
6. Other Skin Conditions: Finally, other skin conditions, such as acne and hidradenitis suppurativa, have also been linked to the development of IPH. This suggests that there may be some common underlying factors that contribute to the formation of nodules or cysts on the palms and soles in these conditions.
7. Hormonal factors – Hormonal factors may also contribute to the development of IPH. This is because the condition tends to occur more frequently in women than in men, and may be associated with hormonal changes that occur during puberty, pregnancy, and menopause. In addition, some studies have suggested that IPH may be associated with an imbalance in sex hormones such as androgens and estrogens.
8. Environmental factors – Environmental factors may also play a role in the development of IPH. Exposure to certain chemicals or substances, such as tobacco smoke or heavy metals, may increase the risk of developing this condition. In addition, IPH may be more common in people who live or work in hot, humid environments.
9. Autoimmune factors – Autoimmune factors may also contribute to the development of IPH. This is because the condition is often associated with other autoimmune disorders, such as rheumatoid arthritis, lupus, or psoriasis. In addition, some studies have suggested that IPH may be caused by an abnormal immune response to the sweat glands, leading to inflammation and damage.
10. Bacterial factors – Bacterial factors may also play a role in the development of IPH. This is because the condition is often associated with bacterial infections, such as Staphylococcus aureus. It is believed that these bacteria may infect the sweat glands, leading to inflammation and the formation of abscesses.
11. Lifestyle factors – Lifestyle factors may also contribute to the development of IPH. For example, smoking, poor hygiene, and a sedentary lifestyle may increase the risk of developing this condition. In addition, certain medications, such as lithium or antiepileptic drugs, may also increase the risk of developing IPH.
12. Psychological factors – Psychological factors may also play a role in the development of IPH. This is because stress and anxiety may exacerbate the symptoms of this condition. In addition, some studies have suggested that IPH may be associated with depression or other mood disorders.

Symptoms

The main symptoms of IPPH are the development of nodules or abscesses on the palms and soles, which can cause pain, tenderness, and swelling. These nodules can range in size from small, pea-sized bumps to larger, golf ball-sized lumps. They often occur in clusters and may be filled with pus or other fluids.

The nodules and abscesses may also be accompanied by the following symptoms:

1. Pain: The most common symptom of IPPH is pain. The pain may be mild to severe and may be constant or intermittent. It may also be accompanied by a burning or itching sensation.
2. Swelling: The nodules and abscesses can cause swelling of the affected area, which may make it difficult to move the hands or feet.
3. Redness: The skin around the nodules and abscesses may appear red and inflamed.
4. Drainage: The nodules and abscesses may eventually rupture and drain pus or other fluids.
5. Scarring: Over time, the repeated episodes of inflammation and scarring may lead to the formation of permanent scars.
6. Painful nodules or bumps: The most common symptom of idiopathic palmoplantar hidradenitis is the presence of painful nodules or bumps on the palms of the hands or soles of the feet. These nodules are usually small and may be red or skin-colored. They can be tender to the touch and may feel firm or hard.
7. Inflammation: Inflammation is another common symptom of idiopathic palmoplantar hidradenitis. When the nodules become inflamed, the affected area may become red, swollen, and warm to the touch.
8. Open sores or ulcers: As the condition progresses, the nodules may rupture and lead to the formation of open sores or ulcers on the palms of the hands or soles of the feet. These sores can be painful, tender, and may secrete pus or other fluids.
9. Itching: Some people with idiopathic palmoplantar hidradenitis may experience itching in the affected area. This can be mild or severe and may be worsened by scratching.
10. Scarring: In some cases, idiopathic palmoplantar hidradenitis can lead to scarring of the affected skin. The scars may be raised, thickened, or discolored and may be permanent.
11. Sweating: Excessive sweating or hyperhidrosis is another symptom that may be associated with idiopathic palmoplantar hidradenitis. This can occur in the affected area or may be more widespread.
12. Nail changes: In rare cases, idiopathic palmoplantar hidradenitis can lead to changes in the nails, such as ridges or splitting. This is thought to be due to inflammation of the nail matrix.
13. Recurrence: Idiopathic palmoplantar hidradenitis can be a chronic condition, with periods of remission and recurrence. Some people may experience repeated episodes of flare-ups over many years.

Diagnosis

The diagnosis of IPH is primarily based on clinical examination and histopathological findings. However, several diagnostic lab tests can be useful in establishing the diagnosis, assessing disease severity, and monitoring response to treatment.

1. Complete blood count (CBC)- A CBC is a routine blood test that measures the number of different types of blood cells, including white blood cells (WBCs), red blood cells (RBCs), and platelets. In patients with IPH, a CBC may reveal an elevated WBC count, indicating the presence of inflammation or infection.
2. C-reactive protein (CRP) – CRP is a protein produced by the liver in response to inflammation. Elevated levels of CRP in the blood are indicative of an inflammatory process. In patients with IPH, CRP levels may be elevated, indicating the presence of inflammation.
3. Erythrocyte sedimentation rate (ESR) – ESR is a blood test that measures how quickly red blood cells settle to the bottom of a tube. An elevated ESR is a nonspecific indicator of inflammation in the body. In patients with IPH, an elevated ESR may indicate the presence of inflammation.
4. Serum electrolytes – Serum electrolyte tests measure the levels of different ions in the blood, including sodium, potassium, chloride, and bicarbonate. These tests can help detect imbalances that may occur in patients with IPH who are taking certain medications, such as potassium-sparing diuretics.
5. Liver function tests (LFTs) – LFTs are a group of blood tests that measure the levels of different enzymes and proteins produced by the liver. These tests can help detect liver damage or dysfunction, which may occur as a side effect of certain medications used to treat IPH.
6. Renal function tests (RFTs) – RFTs are a group of blood tests that measure the levels of different substances in the blood, such as creatinine and blood urea nitrogen (BUN), that reflect kidney function. These tests can help detect kidney damage or dysfunction, which may occur as a side effect of certain medications used to treat IPH.
7. Autoantibody testing – Autoantibody testing involves measuring the levels of antibodies that target the body’s own tissues. In patients with IPH, autoantibodies may be present, indicating an autoimmune component to the disease.
8. Skin biopsy A skin biopsy involves taking a small sample of skin tissue for examination under a microscope. In patients with IPH, a skin biopsy can help confirm the diagnosis by revealing characteristic histopathological features, such as follicular plugging, perifollicular lymphocytic infiltrate, and abscess formation.
9. Antinuclear Antibody (ANA) – ANA is a blood test that detects antibodies against the nuclei of cells. ANA can be elevated in autoimmune diseases, and IPH has been associated with autoimmune conditions. Therefore, ANA may be ordered to rule out autoimmune causes of IPH.
10. Rheumatoid Factor (RF) – RF is an antibody that is commonly found in patients with rheumatoid arthritis, but it can also be elevated in other autoimmune diseases. Like ANA, RF may be ordered to rule out autoimmune causes of IPH.
11. Culture and Sensitivity (C&S) – C&S is a laboratory test that involves growing bacteria from a sample of pus or fluid collected from a skin lesion. The bacteria are then tested against different antibiotics to determine which ones are most effective in treating the infection. C&S can help guide antibiotic therapy in patients with IPH who have secondary bacterial infections.
12. Imaging studies – Imaging studies such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) can be used to assess the extent and severity of IPH. These tests can also be used to rule out other possible causes of the patient’s symptoms.
13. Human Leukocyte Antigen (HLA) typing – HLA typing is a blood test that determines a person’s HLA genotype. HLA genes are involved in the immune response and are associated with autoimmune diseases. Studies have shown that certain HLA types are more common in patients with IPH, so HLA typing may be ordered to help confirm the diagnosis.

Treatment

The main list of treatments for IPH.

1. Topical antibiotics – Topical antibiotics are often prescribed for the treatment of mild to moderate IPH. They work by reducing the number of bacteria on the skin and preventing infection. Clindamycin and erythromycin are the most commonly used antibiotics for this purpose. Topical antibiotics are generally well-tolerated and have few side effects.
2. Systemic antibiotics – Systemic antibiotics are often used to treat more severe cases of IPH or when topical treatments are ineffective. Antibiotics such as tetracycline, doxycycline, and minocycline are commonly used. They work by reducing the number of bacteria in the body and helping to prevent the formation of new lesions. Systemic antibiotics are usually taken orally and may have side effects such as nausea, vomiting, and diarrhea.
3. Corticosteroids – Corticosteroids are often used to reduce inflammation and pain in the affected areas. They can be applied topically or injected directly into the affected areas. Triamcinolone acetonide is a commonly used topical corticosteroid for IPH. Corticosteroids can have side effects such as skin thinning, stretch marks, and an increased risk of infection.
4. Retinoids – Retinoids are derivatives of vitamin A and are often used to treat severe IPH. They work by reducing inflammation and preventing the formation of new lesions. Acitretin and isotretinoin are commonly used retinoids for IPH. Retinoids can have side effects such as dry skin, chapped lips, and increased sensitivity to the sun.
5. Immunomodulators – Immunomodulators are drugs that modify the immune response in the body. They are often used to treat severe cases of IPH that do not respond to other treatments. Methotrexate and cyclosporine are commonly used immunomodulators for IPH. They can have side effects such as nausea, vomiting, and increased risk of infection.
6. Laser therapy – Laser therapy is a newer treatment option for IPH. It involves using a laser to target and destroy the sweat glands in the affected areas. Laser therapy can be effective in reducing the number of lesions and improving quality of life for those living with IPH. However, it can have side effects such as pain, swelling, and redness.
7. Topical corticosteroids: Topical corticosteroids are anti-inflammatory medications that can help reduce inflammation and itching associated with IPH. These medications are applied directly to the affected skin and are available in various strengths and formulations. Topical corticosteroids are generally safe and effective when used as directed, but prolonged use can lead to skin thinning, discoloration, and other side effects.
8. Topical antibiotics: Topical antibiotics are medications that are applied directly to the skin to treat bacterial infections. In cases of IPH, topical antibiotics can be used to prevent secondary bacterial infections that can occur when the skin is broken by nodules, pustules, and abscesses. These medications are generally safe and effective when used as directed, but prolonged use can lead to antibiotic resistance.
9. Intralesional corticosteroid injections: Intralesional corticosteroid injections are injections of corticosteroids directly into the affected skin lesions. This treatment can help reduce inflammation and pain associated with IPH, but it is generally reserved for more severe cases of the condition. Intralesional corticosteroid injections are generally safe and effective when performed by a qualified healthcare provider.
10. Immunomodulators: Immunomodulators are medications that can modify the immune system to reduce inflammation and improve the symptoms of IPH. These medications are generally reserved for more severe cases of the condition and are associated with significant side effects, including an increased risk of infections and malignancies.
11. Surgery: Surgery may be necessary in severe cases of IPH that are not responsive to other treatments. Surgery can involve the removal of the affected sweat glands, which can provide long-term relief from the symptoms of the condition. However, surgery is associated with significant risks and complications, including infection, scarring, and impaired wound healing.
12. Lifestyle modifications: Lifestyle modifications can help manage the symptoms of IPH and improve overall quality of life. These modifications can include wearing comfortable shoes and gloves, avoiding tight-fitting clothing, and avoiding activities that can cause excessive sweating. Additionally, maintaining good hygiene practices, such as washing the affected areas regularly, can help prevent bacterial infections.

References