Introduction

An autoimmune condition, dermatomyositis is known for causing skin changes and muscle weakness. It’s an inflammatory myopathy. Many first realize something is wrong from a telltale rash in the face, which is sometimes itchy or painful.

While the number of people with dermatomyositis globally is unknown, around 10 in 1,000,000 people are diagnosed with it annually. It’s most typical to first diagnose it in those ages 40 to 60, though for the juvenile version, signs typically begin between ages 5 to 15. About 3 in 1,000,000 children are diagnosed with juvenile dermatomyositis. Females are affected twice as often as males. The cause for dermatomyositis is unknown, but experts believe it’s from both environmental and genetic factors, which cause the immune system to attack the body’s own tissues.

Signs, symptoms and progression of dermatomyositis

The onset of dermatomyositis symptoms can be gradual or acute. The symptoms may be different for each person, though there are some common ones to watch for. The severity of dermatomyositis can vary from mild to severe, with it waxing and waning without obvious cause.

Here are some common symptoms or signs of dermatomyositis:

  • Red or reddish-purple skin rash (heliotrope rash) around the eyelids or across the cheeks and bridge of the nose. This may present in a “butterfly” pattern, extending or just showing on the forehead and scalp.
  • Red bumps on the skin’s hand joints, known as Gottron papules.
  • Red or reddish-purple bumps on the elbows and knees.
  • Skin discoloration on the upper back, neck, and/or shoulders, sometimes in a shawl pattern.
  • Pain and itchiness in the rash area.
  • Edema in the eye area.
  • Muscle weakness in the legs and arms.
  • Joint pain.

Over time, the muscle weakness can worsen, resulting in joint stiffness and muscle wasting in the arms and legs. Dermatomyositis can affect more than just the limbs though, it can also impact the lungs and digestive tract.

Diagnosing dermatomyositis

Doctors use a number of diagnostic measures to determine whether a person has dermatomyositis. These are the typical diagnostic factors.

Clinical exam: A physical examination of the person’s body would include looking for the characteristic signs of a skin rash in the facial area and joints, as well as muscle weakness in the limbs.

Laboratory studies: Blood tests may show elevated levels of muscle enzymes like creatine kinase, aldolase, aspartate aminotransferase, and lactic dehydrogenase. These can indicate the presence of muscle inflammation. The blood tests can also help determine whether autoantibodies are present, assisting with the choice of medication and treatments.

Biopsy: Doctors often do a skin or muscle biopsy to evaluate the tissue under a microscopic lens.

Electromyography: An abnormal EMG, which tests the muscle activity, can indicate whether various muscles are affected or weakened.

Imaging: A chest X-ray can show the existence of lung damage, potentially as a result of dermatomyositis. An MRI can reveal inflammation over larger areas of the body.

Capillaroscopy: Nailfold capillaroscopy is shown to be a potentially useful tool to assess disease activity in new-onset of dermatomyositis. Researchers found that the number of enlarged capillaries was positively correlated with the patient’s symptoms, observed by the clinician.

Complications and treatment of dermatomyositis

Dermatomyositis can lead to a number of complications, in addition to muscle wasting. These are possible health conditions some with dermatomyositis may encounter:

Swallowing difficulty: Dermatomyositis can affect the gastrointestinal tract. It may affect the esophageal muscles, leading to difficulty with swallowing, which may result in weight loss.

Aspiration pneumonia: Swallowing problems can lead to breathing issues, especially if the person aspirates saliva, food or liquids into the lungs. That may result in pneumonia.

Breathing difficulty: In addition to the lungs, which can be affected by dermatomyositis, the chest muscles can also be impacted. These problems might lead to shortness of breath or difficulty breathing. A person might ultimately develop interstitial lung disease, which can scar the lung tissue, so the lungs stiffen.

Calcium deposits: A more common issue with juvenile dermatomyositis, calcium deposits may occur in a person’s skin, muscles, and connective tissues during the disease progression.

Development of other autoimmune disorders: Dermatomyositis is associated with potential development of other autoimmune issues, like Raynaud’s syndrome, lupus, scleroderma, rheumatoid arthritis, and Sjogren’s syndrome.

Cardiovascular disease: Dermatomyositis can lead to heart issues like heart muscle inflammation, congestive heart failure, and heart rhythm problems.

Cancer: Adult-onset dermatomyositis is linked to potentially higher rates of cancer development, especially ovarian cancer. The cancer risks are highest during the first three years after dermatomyositis symptoms appear.

Dermatomyositis treatment is not curative, but rather involves symptom management. Corticosteroid drugs are the typical treatment, though it’s also common to prescribe immunosuppressants, exercise, and physical therapy for symptom management. Topical medications can be used for the skin rash issues.

The clinicians most often involved in treating dermatomyositis are dermatologists, neurologists, orthopedists, and physical therapists.

Capillaroscopy for monitoring and screening

Nailfold capillaroscopy is a noninvasive way to visualize and understand a patient’s microvascular abnormalities, which are often present in those with autoimmune rheumatic diseases. Researchers recommend the tool for determining which patients may develop dermatomyositis or understand which patients may have a poor prognosis. It can provide pertinent information about the patient’s disease, to help make an early diagnosis.

The capillary abnormalities can be similar to what is seen in nailfold capillaroscopy for patients with systemic sclerosis, as scleroderma-like patterns are seen in 71% of patients with dermatomyositis. That includes marked angiogenesis and other architectural derangements. Capillary loss is associated with diseased muscle. When those with dermatomyositis stabilize their disease, these nailfold changes improved. That includes improving formerly enlarged or hemorrhaged capillaries. Researchers recommend using nailfold capillaroscopy for evaluating disease and therapeutic activity.

Nailfold capillaroscopy is easy to perform, but analyzing the results can be more challenging, especially to do consistently. Capillary.io was founded by a physician to help other doctors with capillaroscopy quantification and measurements for various nailbed characteristics. The software uses an AI algorithm to perform these measurements, and to generate customized or standardized analysis reports to use in patient evaluation and treatment. Those conducting research can also use these images for those purposes, sharing them with fellow researchers in the same group. Capillaroscopy is a good tool for diagnosing and monitoring autoimmune diseases like dermatomyositis, as long as the interpretations are consistent and accurate.

To learn more about how Capillary.io’s algorithm can improve your analysis and save you time, reach out to us for a demonstration.