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Dermatomyositis

DERMATOMYOSITIS

What are the aims of this leaflet?

This leaflet has been written to help you understand more about dermatomyositis. It tells you what it is, what causes it, how to recognise some of the symptoms, what can be done about it, and where you can find out more.

What is dermatomyositis?

Dermatomyositis is a rare condition that causes inflammation in both the skin and the muscles. The word comes from the Latin for skin (dermis), muscles (myos), and the word for inflammation (-itis).

What causes dermatomyositis?

The exact cause of dermatomyositis is unknown. We do know that the body’s own immune system, which should defend us, begins to attack the skin and muscles leading to inflammation. This is known as an “autoimmune condition”.

Who gets dermatomyositis?

Dermatomyositis is a rare condition, and it is known to affect women more than men. While dermatomyositis can occur at any age, even occasionally in children, it is commoner in adults over the age of 50.

What are the symptoms of dermatomyositis?

Dermatomyositis affects the skin and the muscles. The skin disease usually starts before the muscle disease; however, some people will only have the skin disease. People with dermatomyositis sometimes feel tired and run down.

Dermatomyositis usually affects the muscles involved in movement. Due to the inflammation the muscles become weak and they may also be tender. The muscle weakness may make it difficult to do things that require lifting the arms over the head (like combing or drying the hair) and lifting/stretching the legs (like going up the stairs).

What does dermatomyositis look like?

Dermatomyositis consists of a rash that is sometimes very itchy and usually affects the skin around the eyes, over the knuckles, on the face and “V” of the neck, as well as the cuticles at the base of the nails which may in turn become fragile and discoloured. It may be hard to see, even to a dermatologist.

The rash is often made worse by sunlight, so may be most obvious on areas of the skin which are exposed to the sun.

Are any conditions associated with dermatomyositis?

Dermatomyositis may rarely affect other muscles of the body; however, some possible effects of these are listed below:

  • Gullet (œsophagus)

    If the muscles of the œsophagus (gullet) are affected, the stomach acid can leak up (reflux) into the œsophagus and cause heartburn. This can be treated with acid blocking drugs. If more severely affected, swallowing may be difficult.

  • Lungs

    If the chest wall muscles are affected then some people may develop shortness of breath and have difficulty breathing deeply.

  • Heart

    The heart is also a muscle and can be affected in dermatomyositis, although this is rare. If the heart muscle is affected this can cause palpitations (an irregular or fast heart beat) and dizzy spells. Your doctor may recommend that you have a heart tracing or electrocardiogram (ECG) to check for this.

Calcinosis

Calcinosis is the presence of firm yellow or white lumps of calcium in the skin and sometimes the muscles. This can be painful but may improve once treatment is started. If the lesions become painful and/or are causing functional impairment then surgical removal may be suggested.

Malignancy

In adults with dermatomyositis it is important for doctors to look for signs of any internal cancer. This occurs in some adults with the disease, but only very rarely in children.

A dermatologist is fully aware of the risk of a tumour developing in association with dermatomyositis and will be checking to make sure this is spotted early. Unexpected weight loss, a change in bowel habits, bleeding from the back passage, persistent cough or blood in the urine would be helpful things to be pointed out to the dermatologist at appointments.

How is dermatomyositis diagnosed?

The dermatologist may organise a number of tests including a blood test and a skin biopsy (sample of skin taken for analysis with a microscope). A muscle scan may be done and sometimes a muscle biopsy or electrical test on the muscles is needed.

Can dermatomyositis be cured?

Dermatomyositis cannot be cured, but it often goes away after a number of years and is then said to be in remission. The aim is to control the condition. When the disease is more active, stronger treatments are used and tapered off as it improves. Your dermatologist will be familiar with the treatments mentioned below and will discuss the risks and benefits with you so that you are involved in any decisions.

How can dermatomyositis be treated?

Advice about treatment will be given, after discussion with you, by your dermatologist and also by other specialists if other parts of the body are involved. Some of the possible treatments are listed here:

Corticosteroids

Steroids are often used in dermatomyositis because they act on the overactive immune system to prevent the body attacking itself. Steroids are immune suppressants and are used in many autoimmune diseases. High doses of tablets are given to start with then gradually reduced as the disease gets better. Your doctor may give you acid blocking drugs to help with heartburn and also tablets to prevent bone thinning if steroids are going to be used long term.

Strong steroid ointments are usually given for the skin disease for all areas including the face. The patient leaflet for the ointment may advise against using it on the face; however, because of the severity of dermatomyositis the benefits of use outweigh the risks. If you have any concerns, then this can be discussed with your doctor or dermatologist.

Other immune suppressants

Drugs such as methotrexate and azathioprine are also immune suppressants that have different side effects than steroids. They can be used on their own, or in combination with steroids to help dermatomyositis. Hydroxychloroquine may be useful for treating the rash. More information on these drugs can be found on the British Association of Dermatologists website (www.bad.org.uk).

Self care (What can I do?)

Sun protection

Dermatomyositis is made worse by sunlight. It is therefore advisable to stay in the shade between 11am and 3pm. It is important to wear a high protection sunscreen (SPF 50 or more) to protect against UVB and UVA (look for the UVA circle logo and/or 4 or 5 UVA stars). Apply plenty of sunscreen 15 to 30 minutes before going out in the sun, and reapply every 2 hours.

Protecting your skin with clothing and wearing a wide-brimmed hat that protects your face, neck and ears will further help sun avoidance. Ultraviolet protective sunglasses can also help and in this instance, larger, wrap around sunglasses would offer better protection to the skin around the eyes.

Remember to use the medication as prescribed and let your GP or specialist know if you have any concerns.

You have been given this leaflet because your general practitioner or dermatologist has diagnosed or suspects you have dermatomyositis. Depending on the extent of your condition, there may be sharing of your care between the dermatologist, your general practitioner and other specialist doctors.

Where can I get more information on dermatomyositis?

Web links to detailed leaflets:

http://www.dermnetnz.org/immune/dermatomyositis.html

For details of source materials used please contact the Clinical Standards Unit (clinicalstandards@bad.org.uk).

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: its contents, however, may occasionally differ from the advice given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS

PATIENT INFORMATION LEAFLET

PRODUCED APRIL 2013

REVIEW DATE APRIL 2016

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