What’s wrong with this woman?
A 52-year-old woman presents with a purple rash on her eyelids, purple bumps on the back of her hands, rash on the neck and elbows with proximal muscle weakness (difficulty getting up from a seated position and combing hair)
What is your diagnosis?
Gottron’s Sign (violet papules on dorsal hands predominantly over joints- individual bumps called ‘Gottron’s papules’)
Heliotropic (purple/violet) rash on eyelids
“shawl” sign = purple patch in the distribution of a ‘shawl’ one would wear
psoriasis-like (mild) patches on elbows
Dermatomyositis has a presumed autoimmune etiology. There are essentially three variants of the condition or three variants or closely related manifestations.
- Polymyositis. This is an inflammatory disease of the proximal muscles. This occurs in the absence of any type of cutaneous rash.
- Dermatomyositis. This presents with a violaceous rash, often known as a poikiloderma rash, that occurs on the posterior neck and upper back known as a shawl sign, violaceous or heliotropic rash on the upper eyelids, violaceous patches on the elbows (sometimes mistaken for psoriasis), and a condition known as Gottron’s sign with violaceous papules occurring in an articular pattern on the dorsal hand. The bumps themselves are known as Gottron’s papules, and the overall rash on the back of the hands is known as Gottron’s sign. In dermatomyositis, in addition to the cutaneous rash, there is proximal muscle weakness secondary to proximal muscle inflammation. Oftentimes, patients will complain of difficulty in reaching for objects over their head, combing their hair, and getting up from a seated position such as a couch or commode. In fact, as a resident, I had a patient whose primary complaint was he was upset because he was having difficulty getting cans of Campbell’s chicken noodle soup from the upper shelf in his cabinet. It was his favorite soup and he had it every day for lunch; however, his shoulders had recently developed discomfort when he was reaching for the cans. I looked closely, and he had a very fine rash on his eyelids and on the backs of his hands. He was eventually discovered to have dermatomyositis.
- Dermatomyositis sine myositis. This is where the cutaneous eruption occurs without any proximal muscle weakness.
So, once again, the three variants are dermatomyositis, polymyositis, and dermatomyositis sine myositis. The occurrence is bimodal. Oftentimes, juveniles around the age of 10 can get it, with the second peak occurring in adults around age 50. Children also have an association with collagen vascular disease, vasculitis and calcinosis cutis. Dermatomyositis may also occur in association with other collagen vascular disease such as lupus erythematosus, Sjögren’s syndrome, rheumatoid arthritis, scleroderma, and mixed connective tissue disease. Of interesting note, in adults with dermatomyositis, approximately 25% are associated with internal malignancy, so dermatomyositis certainly can be seen as a cutaneous marker for internal malignancy. The types of malignancies seen reflect those commonly seen for that sex and age. It has been noted that patients with leukocytoclastic vasculitis are at higher risk for having internal malignancy than adults without leukocytoclastic vasculitis. The connection between these two is unclear. Children with dermatomyositis are not at increased risk for developing internal malignancy. The ratio of women to men with dermatomyositis is 6 to 1. There are also associated antimicrosomal antibodies reported with the condition that will be discussed in detail in the accompanying linked articles.
In my experience, I have used a combination of prednisone and methotrexate. Generally speaking, I use prednisone starting at 1 mg/kg, tapering to half that amount over the first six months and then taper down to zero over additional 1½ to 2 years. I also use methotrexate low dose as a steroid-sparing agent, and may reduce the prednisone more rapidly with methotrexate in place (10-20 mg/week). I have even had a few patients who have done quite well on methotrexate alone after an initial prednisone taper. Additionally, there have been other immunosuppressive agents used to treat the condition, which will be attached in the attached links, such as high dose IVIg, cyclophosphamide, chlorambucil, and cyclosporine. In the six to eight patients I’ve treated with dermatomyositis, one had an occult malignancy and other ones were managed quite well with prednisone and methotrexate. Diagnosis can be supported by muscle enzyme studies, cutaneous biopsy showing an interface dermatitis, and EMG. For additional detailed discussion on dermatomyositis, polymyositis, and dermatomyositis sine myositis, please refer to the articles linked below.
Charles E. Crutchfield III, MD
Clinical Adjunct Associate Professor of Dermatology
University of Minnesota Medical School
Medical Director, Crutchfield Dermatology