Definition

Prurigo nodularis is a condition where very itchy bumps form on the skin. Scratching causes the skin to open. Treatment may help ease symptoms.

Causes

The exact cause of prurigo nodularis is not clear. The bumps are more likely form where skin has been scratched or irritated. Nerve problems may play a role.

Risk Factors

Prurigo nodularis is most common in adults between 20 to 60 years old. Things that may raise the risk are:

• Mental health problems
• Reduced function of the liver and kidneys
• Skin conditions that cause itching such as eczema
• HIV
• Certain infections, such as hepatitis
• Type 2 diabetes
• Thyroid disorders
• Certain cancers, such as Hodgkin's disease

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Symptoms

Symptoms of prurigo nodularis are skin lumps that:

• Are small, hard, and very itchy
• May be dry and peeling at the top
• May open and bleed when scratched

Itching may come and go or be constant. Scratching makes symptoms worse. Over time, there may also be some scarring.

Diagnosis

The doctor will ask about symptoms and past health. The diagnosis is usually based on symptoms and a skin exam.

Tests may be done to check for other conditions. They may include:

• Blood tests
• Skin biopsy

Treatment

It may take some time to find the right treatment. The goal is to ease itching and prevent scratching.

Prurigo nodularis may be treated with:

• Medicines applied to the skin, such as steroids, coal tar, vitamin D, or capsaicin
• Steroids or antihistamines taken by mouth
• Corticosteroid injections
• Medicines to change the immune system
• Antidepressants
• Antiseizure medicines
• Antiemetics

If these treatments do not work, other options may be tried such as:

• Cryotherapy—freezes affected skin
• Phototherapy—applies UV light
• Pulsed dye laser—uses a beam of light

The condition can be stressful. Counseling may help.

Prevention

There are no guidelines to prevent this condition. It may help to not scratch skin conditions and bug bites.