Skin rash and muscular weakening are hallmarks of the uncommon immune-mediated muscle disorder known as dermatomyositis. One of the idiopathic inflammatory myopathies is how it is categorized (IIM). While muscular weakness is a common manifestation of all idiopathic inflammatory myopathies, their clinical characteristics and histological findings vary. Skin symptoms typical of dermatomyositis include symmetrical proximal skeletal muscle weakening.

Moreover, it may have an impact on several organ systems, including the gastrointestinal, cardiovascular, and respiratory systems. Dermatomyositis patients frequently have an underlying malignancy, which might change the prognosis of the disease. Although muscle and cutaneous symptoms predominate in most instances, there are various variations of the illness.

Dermatomyositis: Causes

Dermatomyositis may have several genetic, immunologic, and environmental causes, albeit these causes remain unclear.

  • Dermatomyositis  While autoantibodies are found in dermatomyositis patients, it is not known if they are involved in the disease's development

  • Infections  There has been speculation that viruses such as the Coxsackie B virus, enterovirus, and parvovirus can cause dermatomyositis. There are several hypotheses on how viruses cause autoimmunity. They include changes to cellular proteins, self tolerance breaking down, the revealing of previously unknown epitopes, autoantibody-mediated activation of B cells, and molecular mimicry.

  • Drugs  Dermatomyositis can be induced by several medicines. They include D-penicillamine, statins, anti-infectives (penicillin, sulfonamides, isoniazid), non-steroidal anti-inflammatory medicines (diclofenac, phenylbutazone), antineoplastic medications (hydroxyurea, cyclophosphamide), anti-infectives (hydroxyurea, cyclophosphamide), and several vaccinations.

Dermatomyositis: Symptoms

Dermatomyositis signs and symptoms may arise unexpectedly or steadily worsen over time. The most typical warning signs and symptoms are −

  • The skin morphs. The most typical areas for a violet-colored or dusky red rash to appear are your face and eyelids, as well as your knuckles, elbows, knees, chest, and back. Dermatomyositis frequently manifests first as an itchy, uncomfortable rash.

  • Muscular lassitude. The muscles in your hips, thighs, shoulders, upper arms, and neck that are closest to your trunk are those that are affected by progressive muscular weakening. Your body's left and right sides are both affected by weakness, which tends to get worse with time.

The following are potential dermatomyositis side effects −

  • Having trouble swallowing. You may have trouble swallowing if the muscles in your esophagus are harmed, which may result in weight loss and malnutrition.

  • Pneumonia due to aspiration. You could also breathe in food or liquids, including saliva if you have trouble swallowing.

  • Breathing difficulties. You can experience breathing issues, such as shortness of breath if the illness affects the muscles in your chest.

  • Calcium stains. When the illness worsens, these can develop in your muscles, skin, and connective tissues. These deposits appear sooner in the course of dermatomyositis in youngsters and are more prevalent.

Dermatomyositis: Risk Factors

The major risk factors include −

  • Many pharmaceuticals, including statins (cholesterol-lowering drugs)

  • Toxins

  • Infections

  • Cancer or any other disease

  • Hereditary Illness and thyroid

  • Immune disorder

Dermatomyositis: Diagnosis

To diagnose dermatomyositis, your doctor may suggest the following tests −

  • Blood testing. Your doctor will be informed via a blood test whether you have high levels of muscle enzymes, which may be a sign of damaged muscles. The optimum drug and course of therapy may be determined using the autoantibodies that have been linked to various dermatomyositis symptoms that can be found by a blood test.

  • A chest X-ray. This quick test can look for indications of the kind of lung damage that dermatomyositis can occasionally cause.

  • Electromyography. A medical professional with appropriate expertise places an electrode through the skin and into the muscle that will be evaluated. As you relax or contract a muscle, electrical activity is recorded, and variations in the electrical activity's pattern can identify a muscle ailment. Which muscles are impacted can be determined by the doctor.

  • MRI. A scanner uses information produced by a strong magnetic field and radio waves to produce cross-sectional pictures of your muscles. An MRI may detect inflammation across a vast region of muscle, unlike a muscle biopsy.

  • Muscle or skin biopsy. For laboratory analysis, a tiny sample of skin or muscle is taken. Dermatomyositis can be diagnosed using a skin sample. A muscle biopsy may identify muscular inflammation or other issues, such as injury or infection. A muscle biopsy might not be required if the skin biopsy supports the diagnosis.

Dermatomyositis: Treatment

Your doctor may prescribe the following treatments based on the severity of condition −

  • Corticosteroids. Dermatomyositis symptoms can be swiftly controlled with medications like prednisone (Rayos). However, continued usage may result in negative side effects. As a result, your doctor may gradually lower the amount as your symptoms get better after first prescribing a somewhat large dose to control them.

  • Agents that don't use corticosteroids. These medications can reduce the dosage and adverse effects of a corticosteroid when used with it. The two most often used treatments for dermatomyositis are methotrexate and azathioprine. Another drug used to treat dermatomyositis is mycophenolate mofetil, especially if the lungs are affected.

  • Rituximab. Rituximab, which is more frequently used to treat rheumatoid arthritis, is a possibility if other treatments are unsuccessful in alleviating your symptoms.

  • Antibiotics for malaria. Your doctor could suggest an antimalarial drug like hydroxychloroquine if the rash is persistent.

  • Sunscreens. Dermatomyositis rash management involves preventing sunburn on your skin by using sunscreen, wearing protective clothes, and wearing caps.

  • Physical treatment. A physical therapist can recommend a suitable amount of activity for you and demonstrate exercises to help you maintain and develop your strength and flexibility.

  • Speech treatment. Speech therapy can teach you how to adapt to the changes if your swallowing muscles are compromised.

  • Dietetic evaluation. In the latter stages of dermatomyositis, swallowing and chewing may be more challenging. A qualified dietician may show you how to make simple meals.

Dermatomyositis: Prevention

To help prevent skin rashes, you might need to limit your exposure to the sun and apply sunscreen. Antihistamine medications or topical steroid anti-inflammatory creams can be used by your doctor to treat itchy skin rashes.


A multidisciplinary team can handle the uncommon disorder dermatomyositis best, and it could even need to be sent to a tertiary care facility. Given that the majority of patients initially present to a rheumatologist, internist, family doctor, or pediatrician, depending on their age, all doctors must be able to recognize the usual presentation of dermatomyositis.

Testing for muscle enzymes and myositis-specific autoantibodies is part of the initial workup for individuals with suspected dermatomyositis. If the diagnosis is unclear, especially in individuals who lack distinguishing signs, electromyography, muscle, and skin biopsies may be performed.

Depending on the kind of accompanying issues, consultations with different experts may be necessary for addition to a thorough evaluation and assessment for malignancy. Patients with underlying cancer, for instance, should be referred to oncology. Extra muscle symptoms need seeing a pulmonologist, gastroenterologist, cardiologist, and speech therapist.

Patients who are resistant to therapy with glucocorticoids alone, develop additional muscle problems or have significant weakness should get concurrent treatment with glucocorticoids and immunosuppressants.

All patients with skin conditions are advised to avoid the sun and use sun protection precautions. Resistance training should be begun as soon as the condition is detected since it can enhance everyday functioning. To track the progression of the illness and check for systemic problems, cancer, and the adverse effects of medication, patients should have routine follow-up visits.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha


Updated on: 26-Apr-2023


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