Dermatomyositis is a rare inflammatory disease characterized by a distinct skin rash and muscle weakness. This condition is more commonly seen in females than in males. It usually affects adults between 40-60 years of age and children between 5 to 15 years of age. In patients with dermatomyositis, muscles of the shoulder, thigh, hip, upper arm and neck are commonly affected. There is no cure for the disease and its treatment aims at managing the symptoms.
SIGNS AND SYMPTOMS
The following are the signs and symptoms of dermatomyositis:
Skin changes: Skin may develop violet-colored or dusky red rash on face, knuckles, elbows, knees, chest and back. This rash is painful and itchy.
Muscle weakness: The muscles which are located close to trunk such as, muscles of neck, shoulder, thigh, upper arms and hips are affected initially. It then progresses to the muscles of the extremities. Muscle weakness is present on both sides of the body.
Pain: Pain and tenderness commonly occurs in the affected muscles.
- Hard calcium deposits under the skin, (commonly seen in children)
- Unintentional weight loss
- Difficulty in swallowing
- Lung problems
CAUSES AND RISK FACTORS
The exact cause of dermatomyositis is unknown. However, it bears some resemblance with autoimmune diseases wherein the immune system mistakenly attacks its own healthy body tissues. People infected with HIV are immunocompromised and are thus prone to develop this condition. Exposure to certain drugs (penicillamine, cimetidine) can also trigger this condition.
The following are the some of the complications of dermatomyositis.
- Difficulty in breathing
- Lung infections
- Gastric ulcers
- Weight loss
- Skin ulcers
Dermatomyositis may increase your likelihood of developing the following conditions:
- Cancers: Cancers of cervix, lungs, pancreas, breasts and ovaries are known to be strongly linked with dermatomyositis.
- Other connective tissue diseases such as lupus, rheumatoid arthritis, scleroderma and Sjogren's syndrome can occur or overlap with dermatomyositis.
- Raynaud’s phenomenon is a condition of fingers, toes, cheeks; nose and ear turning pale upon exposed to cold temperature.
- Interstitial lung disease may occur along with dermatomyositis.
- Myocarditis (inflammation of cardiac muscle) can occur following dermatomyositis.
The doctor may discuss medical history and perform the physical examination. The following teste help to confirm dermatomyositis
Blood analysis: Blood sample is analysed to detect the elevated levels of muscle enzymes.
Chest X-ray: It is done to confirm the lung damage, which may occur at times along with dermatomyositis.
Electromyography: The doctor would insert a thin needle electrode into the muscle to record the electrical activity of the muscle. Abnormal electrical activity indicates muscle damage.
Magnetic Resonance Imaging(MRI): It creates cross-sectional images of muscles under powerful magnetic field and radio waves. This imaging test is helpful to assess muscle inflammation.
Skin or muscle biopsy: The doctor will extract a skin or muscle sample and send it for biopsy. In this procedure, the sample is examined under a microscope in a laboratory. It is useful to confirm the diagnosis of dermatomyositis.
Corticosteroids: Corticosteroids such as prednisone are potent anti-inflammatory drugs. However, long-term use of corticosteroids is associated with serious side effects.
Corticosteroid-sparing agents: Drugs such as azathioprine and methotrexate are usually prescribed in combination with corticosteroids. These drugs decrease the dose and side effects of corticosteroids.
Antimalarial medications: The doctor may prescribe hydroxychloroquine to treat the persistent rash.
Physical therapy: The muscle strength and flexibility can be improved by practicing the exercises under the guidance of a physical therapist.
Speech therapy: It helps to improve the functioning of speech muscles.
Dietetic assessment: Oesophagal muscle weakness may cause difficulty in chewing and swallowing the food, for which a dietitian may suggest foods that are easy-to-eat.
SURGICAL AND OTHER PROCEDURES
Surgery: Painful calcium deposits can be removed surgically to prevent skin infections in dermatomyositis.
Intravenous immunoglobulin (IVIg): It is the purified blood product containing antibodies from several donors. These antibodies can interfere or block the damaging antibodies which attack the skin and muscle in dermatomyositis.
Wearing hats, protective clothing and application of sunscreen protects from sun, and in reducing skin irritation in patients with dermatomyositis.