Introduction

Prurigo nodularis is a long-term condition affecting the skin. Specifically, prurigo nodularis causes multiple itchy bumps, which may be pink, brown, or black, across the arms and legs. The condition can come and go or persist continuously. The severity of prurigo nodularis can vary and can be very distressing for some patients. What causes this condition isn’t completely understood, but, it is often accompanied by other conditions affecting the skin. Typically, a dermatologist, that is a physician who specialises in skin diseases, can diagnose the condition through a patient history and physical examination. 

Diagnosing prurigo nodularis involves ruling out other diseases that may present similarly. Treating this disease often involves multiple forms of therapy, including at-home and in-hospital treatments. Furthermore, how prurigo nodularis is treated most successfully can vary from patient to patient, potentially involving topical therapies, systemic therapies, phototherapy, psychological support, surgery, and lifestyle modifications.¹

Diagnosis of prurigo nodularis

Patient history

A patient history involves a physician asking you questions about your current and past health, including your current signs and symptoms, past conditions you may have been diagnosed with, medications you have taken, your family history, and your social life. This is also an opportunity to share your ideas and concerns, as well as ask any questions you may have.^{1 2}

Physical examination

A physical examination involves a physician inspecting your body for any abnormalities. It is during a physical examination that a physician can take a look at your skin and potentially diagnose the condition affecting it and is therefore the typical way in which prurigo nodularis is diagnosed.¹

Differential diagnosis

Diagnosing prurigo nodularis involves ruling out other diseases that may present similarly:¹

• Lichen simplex chronicus
• Lichen planus
• Scabies
• Keloid scars
• Dermatofibroma

Topical therapies for prurigo nodularis

Cream

The main topical therapy for prurigo nodularis is a corticosteroid cream. This cream should be applied each night for two to four weeks and the area it is applied to should be covered with plastic wrap.⁴

Injections

Triamcinolone is a type of corticosteroid that can be injected into the lesions caused by prurigo nodularis, which causes the lesions to be flattened and itchiness to be reduced.⁴

Though triamcinolone can help relieve signs and symptoms of prurigo nodularis, it can cause several side effects:

• Aggression and agitation
• Blurred vision
• Dizziness
• Palpitations
• Shortness of breath
• Swelling of hands, fingers, legs, and feet
• Weight gain

Medications for prurigo nodularis

Antihistamines

Antihistamines can be used to treat prurigo nodularis and can be particularly helpful for relieving itchiness. Commonly, however, antihistamines can cause dizziness, drowsiness, and weakness.³

Immunosuppressants

In cases where prurigo nodularis is particularly severe, immunosuppressants may be a suitable treatment option. However, immunosuppressants do present risks:⁴

• Infections
• Vomiting
• Acne
• Headaches
• Tiredness
• Weight gain

Making certain lifestyle changes can help ensure you stay healthy whilst taking immunosuppressants. These measures include washing your hands regularly, keeping up to date with vaccines, having a nourishing diet, and ensuring you are well rested.

Opioid receptor antagonists

Opioid receptor antagonists are a class of medications that may be used in the treatment of prurigo nodularis when other treatments haven’t been effective. Typically, these medications are administered through one dose per day. Side effects typically are restricted to the first two weeks of treatment and include nausea, tiredness, dizziness, heartburn, and diarrhoea.⁴

Phototherapy for prurigo nodularis

Phototherapy involves light being exposed to an area of the body, with smaller devices or in rooms that have walls lined with light sources and can be an effective therapy for various skin conditions, including prurigo nodularis.^4,5

Patients with certain conditions shouldn’t have phototherapy as it may be harmful to their health.⁵

• Dysplastic naevus 
• Systemic lupus erythematosus
• Dermatomyositis
• Genetic skin cancer syndromes
• Bloom syndrome
• Cockayne syndrome

To further protect your health when undergoing phototherapy, certain precautions should be taken. Before entering a room for phototherapy, you should be wearing coverings on the face and genitals. It is also important that, after undergoing phototherapy, you wear sunscreen and sunglasses during the daytime.⁵

Phototherapy is considered a safe treatment method, but, even with safety measures in place, phototherapy carries several risks:⁵

• Redness of the skin
• Burning of the skin
• Swelling
• Skin blisters
• Pain

Psychological support for prurigo nodularis

The long-term nature of prurigo nodularis can make this condition particularly distressing. The itchiness of prurigo nodularis and the changes in the skin’s appearance are key aspects of the disease that patients may struggle to cope with. Nonetheless, psychological support can help you overcome this distress. Psychological support can take many forms and what is most suitable can vary from patient to patient. Psychological support may include consultations with a therapist, in person or online, or attending support groups with those who are also coping with skin conditions. Stress can worsen prurigo nodularis, so psychological support can help prevent the condition from worsening.^2,6

Cognitive behavioural therapy is a technique commonly used during therapy. Through multiple sessions, cognitive behavioural therapy aims to address and modify your beliefs and thoughts to change your behaviour and improve your mood. Cognitive behavioural therapy is tailored to each patient to address their specific concerns.⁷

Lifestyle modifications for prurigo nodularis

Several changes to your lifestyle can be made to improve prurigo nodularis and to make living with prurigo nodularis easier.¹

• Keep nails short
• Cover lesions with bandages
• Wear clothing that covers the lesions
• Wash skin with gentle cleansers
• Keep skin well moisturised
• Use calamine lotions or menthol-containing lotions to help relieve itchiness
• Stay in cool environments as much as possible
• Try to reduce your stress

FAQs

Are there any at-home therapies for prurigo nodularis?

The most effective therapy for prurigo nodularis can vary from patient to patient. At-home therapies may not be the most effective treatment but can be used to improve the condition. At-home therapies include keeping nails short, covering lesions with bandages, wearing clothing that covers the lesions, washing the skin with gentle cleansers, and keeping skin well moisturised.¹

Are there any associated risks with any of the treatment options for prurigo nodularis?

Some treatment options for prurigo nodularis have some associated risks. Phototherapy and medications, such as antihistamines, immunosuppressants, and opioid receptor antagonists, all carry certain side effects. Consulting with your doctor can help you understand the risks and benefits of a treatment before you commence it.⁴

Can prurigo nodularis be cured?

As different patients can respond differently to each treatment, there is not an established cure for prurigo nodularis.¹

What should I do if signs and symptoms of prurigo nodularis worsen after treatment?

If signs and symptoms of prurigo nodularis worsen after treatment, your doctor may be able to formulate a different treatment plan for you to improve your condition.⁴

Summary

Prurigo nodularis causes very itchy bumps, often coloured pink, brown, or black, on the skin over the arms and legs. Prurigo nodularis is a long-term condition that can come and go or persist continually and can also vary in severity, being very distressing for some patients. 

Diagnosing the condition can often be done through a patient history and physical examination. As the condition can vary from patient to patient, management and treatment of the condition varies as a result, potentially involving topical therapies, medications, phototherapy, psychological support, surgery, and lifestyle modifications.