Nodular Prurigo

 

What are the aims of this leaflet?

This leaflet has been written to help you understand more about nodular prurigo (NP). It tells you what it is, what causes it, what can be done about it, and where you can find out more about it.

What is nodular prurigo?

‘Pruritus’ is the medical term for itching. ‘Prurigo’ is a related word, which describes the changes that appear in the skin after it has itched and been scratched for a long time. In nodular prurigo these changes take the form of firm very itchy bumps (nodules) on the skin’s surface. These will resolve when the person stops scratching the area, although in many cases this can be very difficult without proper treatment.

What causes nodular prurigo?

It is not known what causes NP, or makes the skin react in this way. However, once the skin has become itchy, scratching and rubbing will cause the skin nerve endings to become thicker and cause more itching; this in turn will make the condition worse.

• NP may start after an insect bite in a few people.
• Patients, under stress, are more likely to scratch. Stress can therefore make NP worse.
• Up to 80% of people with NP are atopic (i.e. have asthma, eczema or hay fever).
• Other conditions can create lesions similar to NP. If this is suspected your doctor may request blood tests to confirm diagnosis.

Is NP hereditary?

No.

What are the symptoms of NP?

The itching can be very distressing; severe enough to disturb sleep at night and daytime activities. It is often very difficult not to scratch the skin lumps, which may bleed, itch and become infected.

What does NP look like?

The skin shows many bumps hard areas that are intensely uncomfortable. They may be darker than the skin around them. They have a rough rather warty surface and may have a scab or scratch mark on top. The lumps are usually less than 1cm in diameter and can feel firm, be tender, as well as crusty and itchy.

The arms and legs are the most commonly affected areas, but the back, buttocks, shoulders and chest can be affected too. There may additionally be some discoloured scars in the affected areas from deep scratching. NP is most common between 20 and 60 years of age, however, may be present in any race and equally between sexes. The number of nodules may increase with time.

How is NP diagnosed?

Symptoms of itching, and the typical skin lesions described above, are usually enough to make the diagnosis of NP. If there is any doubt then your doctor can carry out a skin biopsy (cutting out one of the bumps under a local anaesthetic to examine under the microscope); this can help to confirm the diagnosis.

Can NP be cured?

No. It is difficult to clear nodular prurigo, but it can usually be controlled and should therefore gradually improve. People are advised not to scratch or rub the nodules, which may slowly resolve and disappear. However, the area of skin may still be very itchy for several weeks.

How can NP be treated?

The treatments for NP are aimed at stopping the skin itching:

• A steroid cream or ointment will usually be suggested first as an attempt to reduce the inflammation in the skin. It should be applied once or twice a day. The strength of the steroid used will depend on the age, where the nodules are, and on the severity of the problem. Injecting a small amount of a steroid into a particularly itchy nodule, or covering it with steroid tape, can sometimes help too.
• Covering the skin with an ointment or a paste bandage can increase the effect of the steroid. It also helps to reduce the itch and the damage to the skin caused by scratching or rubbing.
• An antihistamine tablet or syrup can help to reduce the feeling of itch. Those that work best for NP can cause drowsiness, so should not be taken if driving or using machinery. If you require antihistamine tablets or syrup that would not cause drowsiness, it would be advisable to consult your pharmacist. Some tablets have both antihistamine and anti-stress effects, such as doxepin, and can be helpful taken at night.
• Ultraviolet light treatment, given in the hospital, can help to reduce the quantity of nodules, new nodules appearing or the itch/scratch syndrome.
• If NP is very severe and causing distress, immune-supressing treatments such as steroid tablets, ciclosporin orazathioprine can be prescribed to help reduce inflammation; it is important to note that these treatments may cause additional side effects. Thalidomide can help severe NP but it is usually not given to females who might possibly become pregnant as it can damage the unborn baby.

What can I do?

The most important but hardest thing to do is to stop scratching.

• Anything you can do to take your mind off the itching will help to reduce or stop the scratching. Ask your family and friends to remind you gently if they notice that you are scratching – it is easy to get into the habit of scratching, and you can do it without being aware.
• You may find that laying a cool damp flannel on the skin can reduce the feeling of itch. A cooled emollient (moisturiser) which has been kept in the refrigerator, or has added menthol, may also help.
• Keep your bedroom cool and do not sleep with heavy or heat retaining bedclothes. If you are hot and itchy during the day a fan can help to cool the skin down.
• Emollients (moisturisers). NP patients usually have dry skin, and therefore emollients may help to moisturise dry skin. They ease itching, reduce scaling, soften cracked areas and help the penetration of other topical treatments. They should be used as a soap substitute when bathing or washing, and should also be put on before treatment.

Where can I get more information?

Links to patient support groups:

Nodular Prurigo UK
136 Bedford Street South
Liverpool, L7 7DB
Web: www.nodular-prurigo.org.uk
E-mail: info@nodular-prurigo.org.uk