Dermatomyositis is an uncommon condition that causes inflammation of the muscles by muscle weakness and a distinctive skin rash. Dermatomyositis causes skin rashes on the face and on the back of the hand, as well as muscle pain and tenderness. The rash looks patchy, with purple or red discolorations, and typically  develops on the eyelids and affects the muscles used to extend or straighten joints ( knuckles, elbows, knees, and toes).  Red rashes may also occur on the face, neck, shoulders, upper chest, back, and other areas of the body. It can sometimes even affect the joints, lungs and heart. Dermatomyositis can affect both children and adults; however, it is more common in females than in males.



Signs and symptoms of dermatomyositis include:

  • Red skin rashes on the face and eyelids
  • Skin patches and discoloration around the nails, knuckles, elbows, knees, chest, and back
  • Muscle weakness and tenderness in the hips, thighs, shoulders, upper arms and neck
  • Muscle pain
  • Shortness of breath
  • Unintentional weight loss
  • Fever
  • Tiredness



The exact cause of dermatomyositis is unknown; however it may be caused by a initial viral or bacterial infection. Dermatomyositis is usually an autoimmune disease and it is not known why the immune system breaks down and mistakenly attacks the body tissues. It can be associated with other autoimmune diseases such as thyroid disease and diabetes, as well as cancer. 


Risk factors 

A few factors that can increase the risk of developing dermatomyositis include:

  • Being female (more common in women than in men)
  • Children between the ages of 5 and 15
  • Adults between the ages of 40 and 60



Possible complications of dermatomyositis include the following:

  • Difficulty breathing (may lead to chest pain and shortness of breath)
  • Difficulty swallowing (may lead to malnutrition and unintentional weight loss)
  • Lung disease (may lead to dry cough and shortness of breath)
  • Inflammation of the heart (may lead to heart failure and heart arrhythmias)
  • Joint pain (may lead to difficulty extending of straightening joints)
  • Calcium deposits (can occur in the muscles, skin and connective tissues)
  • Ulcers
  • Cancer