Dermatomyositis: Types, Epidemiology, Causes, Signs, Symptoms, Treatment, Investigations
Dermatomyositis is a rare inflammatory disorder usually characterised by a distinctive skin rash and muscle weakness.
Children and adults both get affected with dermatomyositis. Dermatomyositis usually affects adults in the age group of 40 to 60 years whereas in children this is seen in the age group of 5 to 15 years of age. Dermatomyositis is more commonly seen in females when compared to males.
Treatment helps in regaining muscle strength and function along with clearing the skin rash.
Types of Dermatomyositis
Types Of Dermatomyositis Include:
- Amyopathic dermatomyositis.
- Dermatomyositis with cancer.
- Childhood dermatomyositis.
- Primary idiopathic dermatomyositis.
Epidemiology of Dermatomyositis
About 9.63 dermatomyositis cases have been recorded in a population of a million. AMD reaches about 2.08 cases in a population of a million.
Dermatomyositis can affect an individual at any age. Dermatomyositis affects adults in their 50s. Dermatomyositis affects children in the age group of 5 to 10 years. However, both men and women get affected with dermatomyositis, but women are more prone to the disorder when compared to men.
Causes of Dermatomyositis
The exact cause of dermatomyositis is still not known, but the suspected cause may implicate towards autoimmune disorders which are usually responsible for forcing the immune system of the body to attack its own healthy tissues.
Generally, the immune system of the body acts as a shield in order to protect the cells from the attacks of the foreign bodies like viruses and bacteria. In case of dermatomyositis, the immune system starts producing autoimmune antibodies that attack the healthy tissues of the body. Individuals suffering from dermatomyositis may also develop autoimmune antibodies in their blood.
Dermatomyositis specifically may also affect the small blood vessels present in muscular tissue. Degeneration of muscle fibers may also result due to blood vessels being surrounded by the inflammatory cells.
Signs and Symptoms of Dermatomyositis
The Common Symptoms Of Dermatomyositis Include:
- Skin Changes: A dusky red or violet-colour rash appears on eyelids, face and on areas around elbows, back, chest, knuckles, nails and knees. A patchy bluish-purple discoloured rash is the first sign of dermatomyositis.
- Muscle Weakness: Progressive weakness of the muscle closest to the trunk like shoulders, upper arms, hips, neck and thighs. This weakness may be symmetrical and affect both the right and left sides of the body and worsen gradually.
Other Symptoms May Include:
- Hardened deposits of calcium below the skin (calcinosis), particularly in children.
- Lung problems.
- Weight loss.
- Muscle pain.
- Gastrointestinal ulcers and intestinal perforations, more common in children.
Treatment for Dermatomyositis
There is no proper cure available for treating dermatomyositis. Treatment for dermatomyositis usually concentrates on improvement of skin condition and functioning and strengthening of muscles. Starting the treatment as early as possible increases the effectiveness of treatment and decreases the chances of complications.
Although there is no particular treatment available for treatment of dermatomyositis, given below are few of the treatment modalities which usually help in controlling the symptoms.
Corticosteroids: Corticosteroids are the first step towards treatment of dermatomyositis in most of the cases. Corticosteroids include cortisone and prednisone which help in suppressing the immune system and reducing the muscle inflammation and thus helps in improving functioning and strengthening of the muscles. Topical corticosteroids are prescribed for the skin. Treatment with corticosteroids begins with a high dose and the dose is gradually decreased with improvement in signs and symptoms. Improvement in symptoms may be noticed in about two or four weeks, but the treatment with corticosteroids may continue for several months. Corticosteroids if taken for prolonged period carry certain severe side effects and therefore the dose is gradually tapered down as much as possible. Supplements such as calcium or vitamin D may also be recommended to overcome the severe side effects that may arise due to corticosteroids.
Additional Immunosuppressive Therapies: Immunosuppressive medications are the second step taken for the treatment of dermatomyositis. These medicines are prescribed only when corticosteroids fail to work satisfactorily. Immunosuppressive medicines may include:
- Corticosteroid-Sparing Agents: Corticosteroid-sparing medications when taken in combination with corticosteroids usually help in decreasing the dose and hence decrease the risk of side effects from the corticosteroids. Corticosteroid-sparing medications may include methotrexate and azathioprine in combination with prednisone.
- Intravenous Immunoglobulin: Intravenous immunoglobulin is a blood purifier containing healthy antibodies from many blood donors. Intravenous immunoglobulin helps in blocking the antibodies which attack skin and muscles in dermatomyositis. Intravenous immunoglobulin is given as an infusion through a vein. These infusions need to be performed every six to eight weeks.
- Immunosuppressive Agents: Immunosuppressants like cyclosporine and cyclophosphamide may help in improving signs and symptoms of interstitial lung disease in dermatomyositis.
Biological Therapies: Biological therapies are the third step taken for the treatment of dermatomyositis. This is generally performed in very severe cases when other treatments fail to work properly. However, these are still under trials as there is not enough scientific evidence as to the effectiveness of treatment with these agents. Patient needs to be closely monitored when this route is adopted.
- Rituximab has been found to be effective in some cases in addressing the skin rash and improving muscle strength.
- Tumor necrosis factor (TNF) inhibitors like etanercept and infliximab may be used for treating the inflammation.
Antimalarial Medications: Antimalarial medications are usually prescribed for a persistent rash. Antimalarial medications may include chloroquine and hydroxychloroquine.
Pain Relievers: Over-the-counter drugs like ibuprofen, acetaminophen and aspirin help in treating pain. If these do not work, stronger pain relievers like codeine are also prescribed.
Physical Therapy (PT): Exercises help in maintaining and improving the flexibility and strength.
Surgery: Removal of painful calcium deposits may help in preventing recurrent skin infections.
Investigations for Dermatomyositis
A complete subjective and physical examination is necessary to diagnose the condition of dermatomyositis.
Tests For Diagnosing Dermatomyositis May Include:
- Magnetic resonance imaging (MRI).
- Muscle biopsy.
- Bloods test to check levels of aldolase and creatine phosphokinase.
- Skin biopsy.