What Are the First Signs of Dermatomyositis?

Early symptoms of dermatomyositis include skin rashes with breakouts mostly on sunlight-exposed surfaces.

Dermatomyositis is a condition that can cause muscle inflammation and skin rashes. It may also affect the lungs.

Early symptoms of dermatomyositis include skin disease. Characteristics of the skin rashes include:

• Breakouts mostly on sunlight-exposed surfaces
• Itching skin lesions, may be so intense they disrupt sleep
• Face redness
• Breakouts along the eyelid edges, with or without swelling around the eyes
• Breakouts on the back of the hands, especially over the knuckles
• Changes around the fingernails
• Breakouts on the upper outer thighs
• Scaly scalp or diffuse hair loss

Muscle disease in dermatomyositis may occur before the skin rashes, it may accompany the skin rashes, or it may occur after the skin disease by weeks to years. Characteristics of muscle involvement include:

• Muscle weakness that affects both sides of the body, involving the muscles closest to the trunk of the body such as those in the thighs, hips, shoulders, and neck
• May progress slowly over time
• Muscle fatigue/weakness when climbing stairs, lifting or reaching for things overhead, walking, rising from a seated position, combing hair, or swallowing
• Muscle tenderness (not typical but may occur)

About 10% of people with dermatomyositis may develop interstitial lung disease, which can make it difficult to breathe.

Generalized symptoms of dermatomyositis include:

• Fever
• Joint pain
• Feeling unwell (malaise)
• Weight loss
• Raynaud’s phenomenon
• Problems swallowing
• Gastroesophageal reflux (GERD)
• Difficulty speaking/hoarseness
• Heart problems/irregular or fast heartbeats
• Gastrointestinal ulcers and infections (more common in children)
• Lung disease
• Calcium buildup (calcification) under the skin, which may result in joint deformity (more common in children)
• Tiptoe gait in early childhood
• Cancer in adult patients

Symptoms of dermatomyositis often last for several years. 

The cause of dermatomyositis is unknown but it resembles some autoimmune disorders. It is thought genetic, immunologic, infectious, and environmental factors may play a role. 

Some cases of drug-induced dermatomyositis have been reported. Medications thought to trigger the illness include: 

• Hydroxyurea 
• HMG-CoA reductase inhibitors (“statins”)
• Penicillamine 
• Anti–tumor necrosis factor (TNF) drugs 
• Anti–programmed cell death drugs 
• Interferon 
• Cyclophosphamide 
• Quinidine 
• Bacillus Calmette-Guérin (BCG) vaccine 

Diagnosis of dermatomyositis begins with a history and physical exam, which may reveal the skin rash. 

Blood tests and other studies that may be used to diagnose dermatomyositis include:

• Muscle enzyme levels (such as creatine kinase, aldolase, aspartate aminotransferase, lactic dehydrogenase)
• Antinuclear antibody levels
• Myositis-specific antibodies
• Pulmonary function studies with diffusion capacity
• Esophageal manometry
• Electrocardiography (EKG/ECG)
• Pap smear in women for malignancy screening
• Colonoscopy to screen for underlying malignancy
• CA-125 and CA-19-9 for malignancy screening

Imaging may be used to diagnose dermatomyositis, including:

• Magnetic resonance imaging (MRI) of the muscles
• Ultrasound of the muscles
• Chest X-ray
• Barium swallow
• Electromyography
• Imaging to screen for underlying malignancy, including computerized tomography (CT) scan of the chest, abdomen, and pelvis, and transvaginal ultrasound and mammogram for women

In addition, a skin biopsy or muscle biopsy may be used to help diagnose dermatomyositis.

Dermatomyositis is associated with certain types of cancer in adults, so certain tests may be indicated to diagnose or rule out these cancers.

The muscular symptoms of dermatomyositis are typically treated with corticosteroids, along with an immunosuppressive agent. 

Medications used to manage dermatomyositis include:

• Corticosteroids such as prednisone (Rayos) and prednisolone (Prelone, Millipred, Flo-Pred)
• Immunosuppressive drugs such as methotrexate (Trexall, Rheumatrex), mycophenolate (CellCept, Myfortic), azathioprine (Imuran, Azasan), sirolimus (Rapamune), rituximab (Rituxan), cyclophosphamide, cyclosporine (Gengraf, Neoral, Sandimmune), chlorambucil (Leukeran)
• Immune globulins such as intravenous or subcutaneous immunoglobulin (Gammagard, Carimune NF, Gammaplex, Octagam)
• Antimalarials such as hydroxychloroquine (Plaquenil) and chloroquine (Aralen)
• Disease-modifying antirheumatic drugs (DMARDs) such as Leflunomide (Arava)
• Other medications to treat calcinosis such as:
• Diltiazem (Cardizem, Cartia XT, Tiazac, Taztia XT)
• Colchicine (Colcrys)
• Alendronate (Fosamax, Binosto) and pamidronate
• Warfarin (Coumadin)

Surgery to remove tender or painful calcified lesions may also be indicated.

Other lifestyle changes may be helpful in treating symptoms of dermatomyositis, including: 

• Avoiding the sun
• Using sunscreen
• Wearing sun-protective clothing and a wide-brimmed hat
• Physical therapy and rehabilitative measures
• Elevating the head of the bed
• Changing what you eat if you have difficulty swallowing
• Avoiding eating before bedtime

Compilations of dermatomyositis include:

• Severe itching may disrupt sleep and can impact the quality of life
• Calcium deposits under the skin (calcinosis)
• Shortening and hardening of joints (contractures) that may cause deformity and reduced range of motion
• Certain cancers in adults
• Side effects from long-term use of steroids such as weak bones and increased risk of infections