Definition & Overview

Dermatomyositis is a rare form of muscle disease that is often preceded by a distinctive skin rash. The disease leads to general muscle weakness and can be fatal in adults due to known complications, such as cancer, lung disease, pneumonia, malnutrition, and lung failure. This condition belongs to a group of muscle diseases called inflammatory myopathies, which include polymyositis, juvenile dermatomyositis/polymyositis, amyopathic dermatomyositis, and antisynthetase syndrome.

The disease affects every age, gender, and race, but statistics shows that it is more prevalent in women, particularly those between the ages of 50 and 70 years old.

Cause of Condition

The exact cause of dermatomyositis is yet to be identified, but researchers believe that abnormalities in the immune system may play a big role. In fact, many of the disease’s characteristics are similar to those of autoimmune disorders that occur when the immune system mistakenly identify the body’s own tissues as foreign invaders and attacks them.

In dermatomyositis, small blood vessels are the first to be affected and this leads to muscle degeneration.

Key Symptoms

Most people with dermatomyositis develop a distinctive skin rash weeks or even months before the onset of muscle weakness. The rash is usually reddish to bluish-purple in color and may appear in spots or large groups. Many develop the rash in the facial region, particularly the eyelids, nose, and cheeks. However, the rash can also appear on the shoulders, elbows, and chest.

Other symptoms are a scaly scalp, thinning hair, purple spots on bony areas, and purple eyelids. In children and adolescents, the most common symptom is calcinosis, or hard and yellow lumps beneath the skin. Some people may also experience swollen joints, especially in the fingers.

In some people, the rash may not be accompanied by other symptoms, but others may experience itchiness or pain together with the appearance of the rash.

It’s important to note that skin rash often precedes muscle weakness, but in some cases, muscle weakness can appear simultaneously with the rash. The first muscles to be affected are usually those near the trunk, which makes it difficult for the affected person to walk, climb stairs, crouch, and lift heavy objects.

As the condition progresses, patients experience increased difficulty in lifting their arms, combing their hair, and even swallowing.

Who to See & Types of Treatment Available

If you experience the symptoms of dermatomyositis, especially the rash, you should see your doctor as soon as possible. As mentioned earlier, muscle weakness can occur weeks, months, or even years after the appearance of the rash, but they can also occur simultaneously.

To diagnose your condition, the doctor will review your medical history and then perform a thorough physical examination to evaluate the symptoms. Several tests, including an MRI, ECG, skin biopsy, muscle biopsy, and blood tests will also be performed.

If dermatomyositis is confirmed, the doctor will immediately present a treatment plan. Keep in mind that there is no cure for this condition but the symptoms can be managed. In fact, the primary goal of treatment is to manage the skin and muscle disease, and to slow down the rate of progression.

Medications, such as oral corticosteroids and immunosuppressive or cytotoxic drugs help slow down the disease. Other drugs, such as a calcium channel blocker, colchicines, and hydroxychloroquine help manage the symptoms of the skin disorder.

Patients should also take preventive measures to manage their condition. These include avoiding excessive sun exposure, getting enough rest, and eating the right diet.

For serious cases, the doctor may prescribe physical and speech therapy to address muscle and joint weakness as well as swallowing difficulties.

As the condition progresses, it’s likely that the patient will find it increasingly difficult to chew and swallow. The attending physician will then enlist the services of a dietitian to better serve the patient.

Depending on the severity of the condition and the overall health of the patient, the doctor may opt to perform invasive procedures such as transferring purified blood that contains healthy antibodies to block damaging antibodies of the immune system. Surgery to remove calcium deposits can also be an option, especially if the patient is experiencing excessive pain.

Most patients will have to undergo treatment for the rest of their lives. Only around 20% will experience a drastic reduction of the symptoms. Patients who develop other conditions, such as heart and lung diseases or cancer, will likely find it more difficult to recover from dermatomyositis.

Without a known cure, it can be difficult for patients to cope with their condition, especially when it begins to worsen. However, with the right support and positive attitude towards treatment, the possibility of remaining productive for the rest of their lives remains high.

References:

  • Jorizzo JL, Vleugels RA. In: Bolognia JL, Jorizzo JL, Schaffer JV, et al, eds. Dermatology. 3rd ed. Philadelphia, Pa: Mosby Elsevir; 2012:chap 42.
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