Dermatomyositis is the inflammatory disease of the muscle accompanied by skin manifestations (rash). Most healthcare professionals are aware of this uncommon disease, but it is even more uncommon to come across a rare variant of dermatomyositis, called the anti-melanoma differentiation-associated protein 5 (anti-MDA5) dermatomyositis.

Here is a rare case of a 48-year-old man who presented to the dermatology outpatient department with complaints of painful ulcers on his hands. His symptoms initiated around 6 months back with progressive worsening of the ulcerations on the elbows, dorsal surface of the hands, fingertips and in the oral cavity. The dermatological manifestations were also associated with shortness of breath on exertion and a violaceous periorbital eruption.

The patient had no other symptoms like joint pain, joint deformity or muscle weakness or arthritis.

Computed tomography (CT) of the chest was performed which identified irregular, nodular, pulmonary opacities suggestive of organizing pneumonia. Antibody testing revealed positive anti-MDA5. Other investigations like CT scans, colonoscopy and prostate-specific antigen testing showed no evidence of cancer.

A diagnosis of anti-MDA5 dermatomyositis was made.

Anti-melanoma differentiation-associated protein 5 (anti-MDA5) dermatomyositis is a quite rare variant of dermatomyositis. With its aggressive skin manifestations, it often mimics psoriasis. Anti-MDA5 dermatomyositis is associated with milder or absent muscle damage but aggressive skin and pulmonary findings. Lung involvement manifests as rapidly progressive interstitial lung disease (ILD).

Skin and mucosal findings include oral ulcers, tender gums, Gottron’s papules, painful palmar papules, and non-scarring alopecia ( absence of hair/baldness).

Patients with any variant of dermatomyositis should undergo extensive screening for malignancies such as that of the lung, gastrointestinal tract, breast and reproductive organs. Variants, like anti-MD5, that are particularly destructive for the lung should have further investigations, to evaluate the ILD, like PFTs (pulmonary function tests).

Being an autoimmune disorder, the management primarily revolves around the suppression and control of the inflammatory and the immune mechanism. Although the treatment of Anti-MD5 dermatomyositis is debatable, immunosuppressive drugs, like steroids, cyclosporine and anti-TNF have been frequently prescribed to manage the disease.

The patient in the discussion here received immunosuppressive and immunomodulatory drugs. He was prescribed hydroxychloroquine, systemic glucocorticoids, mycophenolate mofetil, and intravenous immune globulin to modulate the body’s responses. To facilitate the blood supply to the hands for better healing, aspirin, pentoxifylline, nifedipine, sildenafil, and botulinum toxin were administered.

Considerable improvement was noticed in the patient’s symptoms at the 5-month follow up. His hand ulcers healed and the lung findings subsided.

References

Alexandra Charrow, M. M. (2019, August 01). Cutaneous Ulcerations in Anti-MDA5 Dermatomyositis. Retrieved from The New England Journal of Medicine: https://www.nejm.org/doi/full/10.1056/NEJMicm1816147

Okogbaa, J., & Batiste, L. (2019). Dermatomyositis: An Acute Flare and Current Treatments. Clinical medicine insights. Case reports, 12, 1179547619855370. https://doi.org/10.1177/1179547619855370

Hall, J. C., Casciola-Rosen, L., Samedy, L. A., Werner, J., Owoyemi, K., Danoff, S. K., & Christopher-Stine, L. (2013). Anti-melanoma differentiation-associated protein 5-associated dermatomyositis: expanding the clinical spectrum. Arthritis care & research, 65(8), 1307–1315. https://doi.org/10.1002/acr.21992