This 50-year-old woman presented with recent onset of an erythematous rash with dusky red mucinous papules on her upper chest and back.
Her general health had always been good and she had no other specific problems, apart from noticing that her eyelids were slightly swollen and had a purple tinge.
On examination, the cuticles of the nails were somewhat ragged, the blood vessels were prominent on the nail folds and there was some scaling on the scalp and thinning of the hair.
A search was made for purple spots on the knuckles, known as Gottron's nodules, other red/purple areas on exposed areas of the skin, suggesting a photosensitivity reaction, and white lumps on the skin (calcinosis). Raynaud's phenomenon was also checked for.
A diagnosis of dermatomyositis was considered and confirmed by the finding of a raised creatinine kinase (CK) and non-specific antinuclear antibodies (ANA) on a blood test and a skin biopsy.
The diagnosis of dermatomyositis can be confirmed by the finding of a raised CK, and sometimes aldolase, aspartate aminotransferase and lactic dehydrogenase. ANA is found in most patients. Skin biopsy should be helpful. For any patient over 60, a full examination should be made to exclude underlying malignancy.
The mainstay of treatment is an oral corticosteroid, such as prednisolone, plus an immunosuppressant such as azathioprine or methotrexate if necessary. Cytotoxic drugs or high-dose IV immunoglobulin are also sometimes used.
Diltiazem or colchicine may help calcinosis, and hydroxychloroquine, high factor sunscreens and topical steroids may help to reduce the ill effects of sun exposure.
In cases of dysphagia, raising the bed head and avoiding food before bedtime may help. Physiotherapy can aid muscle and joint problems. Treatment is likely to be necessary for life, apart from the fortunate 20% who resolve spontaneously. Cardiac and pulmonary complications or malignancy carry a poorer outlook and may have fatal results.
- Discoid lupus erythematosus
- Systemic lupus erythematosus
- Lichen planus
- Polymorphic light eruption
- Tinea corporis
- Graft versus host disease
- Lichen myxedematosus
Dr Watkins is a retired GP in Hampshire