Understanding and managing anti-MDA 5 dermatomyositis, including potential COVID-19 mimicry

Abstract

Anti-Melanoma Differentiation-Associated gene 5 (MDA-5) Dermatomyositis (MDA5, DM) is a recently identified subtype of myositis characteristically associated with Rapidly Progressive Interstitial Lung Disease (RP-ILD) and unique cutaneous features. We reviewed PubMed, SCOPUS and Web of Science databases and selected 87 relevant articles after screening 1485 search results, aiming to gain a better understanding of the pathophysiology, clinical features, diagnosis, and treatment approaches of anti-MDA-5 DM described in the literature. The etiopathogenesis is speculatively linked to an unidentified viral trigger on the background of genetic predisposition culminating in an acquired type I interferonopathy. The clinical phenotype is highly varied in different ethnicities, with new clinical features having been recently described, expanding the spectrum of cases that should raise the suspicion of anti-MDA-5 DM. Unfortunately, the diagnosis is frequently missed despite excessive mortality, calling for wider awareness of suspect symptoms. RP ILD is the major determinant of survival, treatment being largely based on observational studies with recent insights into aggressive combined immunosuppression at the outset.

Dermatomyositis following COVID-19 infection

“…An elevation of its incidence was noticed during the pandemic period coinciding of corona virus [1] . Viral infections could induce autoimmunity and may be the eliciting event in the pathogenesis of myositis [2] . In our case, dermatomyositis is hypothetically linked to viral trigger on the background of genetic predisposition.…”

Knuckle lesions in inherited and acquired disorders

“…The palmar papules are painful and characteristically located on the palmar aspects of the metacarpophalangeal and interphalangeal joints which histologically exhibit occlusive vasculopathy. [ 82 83 ] Papulosquamous lesions on the palmar aspects of the interphalangeal joints (inverse Gottron papules) are also reported as described above.…”

Skin Rash and Interstitial Pneumonia Can Be a Fatal Combination: A Rare Case of Anti-Melanoma Differentiation-Associated Gene 5 (MDA5)-Associated Interstitial Lung Disease

“…As reported by the authors [3] , among patients within this cluster, a small percentage of 22.7% develop RP-ILD. Unfortunately, the diagnosis is often overlooked because the acute presentation with predominant lung involvement may mimic other causes of interstitial pneumonia, including COVID-19 [4] or other viral infections, as occurred in our case. ILD is the most important systemic complication and the major determinant of survival, being often rapidly progressive and associated with a poor prognosis.…”

“…Therapy is still largely empiric and should be individualized. There is a dearth of clinical studies based on observational studies and case reports evaluating the best line of treatment, but there are no guidelines [4,8] . Steroid monotherapy and standard immunosuppressants, such as methotrexate, azathioprine and cyclosporin A, have shown poor results in RP-ILD with a fatal outcome for pulmonary insufficiency in a few months [9] .…”