Prurigo nodularis (PN) is a rare skin rash that causes extremely itchy bumps. The severity of the itch may interfere with sleep or cause distress.
Common PN locations include the abdomen, limbs, and upper back. The rash distribution on the body is often symmetrical. PN bumps can vary in size but average about half an inch, with a dry and rough surface.
One theory for the onset of PN is that changes to the immune system and skin nerves cause an enhanced itching sensation. This triggers scratching, which contributes to the skin rash seen in this condition. PN can also co-occur with other issues like reduced liver or kidney function, and other skin diseases.
But it’s important to know that there are self-care strategies and treatments available, including the first FDA-approved injectable medication for PN.
The goal of PN treatment is to stop the itch-scratch cycle, which describes the way that inflammation from scratching can cause more itchiness. Medical treatments can be effective ways to break this cycle.
PN can be the first symptom of an underlying condition like HIV or lymphoma, so your dermatologist may conduct a thorough exam that includes ordering medical tests. They may also refer you to another type of specialist.
There are several ways that dermatologists treat PN.
Topical medications are the kind you apply to your skin. They can provide relief from itch and reduce inflammation.
A dermatologist may recommend an over-the-counter itch relief medication, such as:
- anti-itch emollient
- capsaicin cream
If these treatments aren’t effective, there are prescription-strength itch-relief medications available, such as calcipotriol.
Topical medications a dermatologist can prescribe to reduce inflammation include:
Your dermatologist might suggest covering your PN rash with medical tape coated in a corticosteroid. The tape helps your skin to absorb more of the medication and creates a protective barrier between your skin and nails to prevent exacerbations from scratching.
Cryosurgery relieves the itch and flattens PN bumps by freezing from a very cold substance, such as liquid nitrogen. A doctor can perform the procedure during an office visit while you’re awake. It usually requires 2 to 4 treatments to experience satisfactory results.
Cryosurgery can leave scarring and lightened areas on people with darker skin tones, so it’s important to discuss both the risks and benefits with your dermatologist.
Corticosteroid injections can flatten PN nodules and relieve itching but may not be appropriate for extensive or widespread use due to side effects.
Phototherapy uses UV light to treat PN. It may help people with large rash areas or who need a stronger treatment than topical medication.
Phototherapy requires multiple sessions, usually 2 or 3 times per week for several weeks.
The excimer laser is one example of phototherapy. It may work for stubborn PN that does not respond to other treatments.
This type of treatment is an oral or injectable medication that works throughout your body. It may be an option for people who live with severe or widespread PN.
- Antihistamines: This type of medication can induce sleepiness and reduce itching while you sleep.
- Antidepressant medication: Some types of antidepressant medications may reduce itching while you’re awake.
- Immunosuppressants: Because of the potentially serious side effects, doctors prescribe immunosuppressant medications only for the PN occurrences that are harder to treat. Common choices include cyclosporin and methotrexate.
- Nerve pain medication: Gabapentin and pregabalin are two types of oral medications that doctors may prescribe for PN.
A 2022 research review examined new treatments for PN that target certain cytokines.
Interleukin 31 (IL-31) is a cytokine of key interest because experts find it 50 times more often in PN lesions than in unaffected skin.
Nemolizumad, a humanized monoclonal antibody, targets the receptor for IL-31, known as IL-31RA. People using nemolizumab injections in a phase 2 trial reported less itching and fewer lesions when compared with the control group. As a result, the FDA assigned nemolizumab the status of Breakthrough Therapy for PN.
Interleukin-4 (IL-4) and its receptor IL-4RA is another focus of research due to the role IL-4 plays in the neural pathways of itching. The monoclonal antibody dupilumab exhibits anti-IL-4RA action, and in treatment, it led to reduced itching and fewer lesions after 3 months.
A 2020 review showed that dupilumab was effective for treating PN. The review indicated it can take about 2 months of dupilumab treatment for significant itch relief, and 4 months to experience complete remission.
A 2021 review showed that dupilumab also works by inhibiting the receptors and signaling pathways activated by certain cytokines involved in inflammation.
There are behavior modifications you can make to ease PN symptoms.
- Avoid touching the affected skin.
- Cover or bandage areas with PN rash.
- Trim your nails so they do less damage to your skin, or consider wearing gloves.
- Use topical anti-itch lotions like calamine, or cream containing menthol or camphor.
- Take antihistamine medication at night so you can sleep. Ensure you take the medication as directed.
- Use fragrance-free products designed for sensitive skin.
- Identify and avoid itch triggers.
- Avoid hot water and scrubbing your skin when you bathe or shower.
- Monitor your skin for symptoms of infection.
It can help to reduce factors that increase PN itching, such as stress, heat, and sweat.
Treating any contributing co-occurring condition you have may ease PN symptoms. Examples include:
- hepatitis C
- end-stage kidney disease
- mental health conditions like depression and anxiety
The flavonoid quercetin may reduce itching, according to a 2017 case report. Quercetin is found in plant foods such as:
- black grapes
- yellow onions
- cherry tomatoes
- green and black tea
Quercetin is more easily absorbable in the presence of dietary fat.
PN is a chronic skin condition that can cause uncomfortable, itchy bumps on the skin.
Several medical and lifestyle options exist with the goal of stopping the itch-scratch cycle, which is how inflammation from scratching can cause additional itchiness.
Topical medications, cryosurgery, corticosteroid injections, phototherapy, medical tape, and body-wide medications are some existing treatment options for PN. New medications, such as the recently FDA-approved injectable biologic medication dupilumab (Dupixent), have also entered the treatment field.
Lifestyle choices such as keeping nails short, managing stress, and identifying triggers can also help during your PN treatment journey. Talk with your doctor to find out what is right for you.