Dr. Larson presented a prototypical case of dermatomyositis with regard to the presence of physical exam findings. Our astute residents readily honed in on a clinical diagnosis of dermatomyositis and turned to the next step, screening for possible underlying malignancy or a comorbid rheumatologic overlap syndrome.
First, please review the 2001 review article in the American Family Physician as a refresher and for additional information on diagnositic testing, differential diagnosis and treatment.
Second, remember the characteristic physcial exam findings associated with dermatomyositis, many of which are pathonomonic for the disease. These include: Gottron's papules, Gottron's sign, heliotrope rash, facial edema, photodistributed poikiloderma (shawl or "V" sign), holster sign, erytheroderma, periungual changes, psoriaform scalp rash and calcinosis cutis.
And finally, recall that there are systemic manifestations as well which commonly include proximal muscle weakness, dysphonia and dysphagia. But can also be complicated by cardiopulmonary involvement including ILD and myocarditis. Thus, there are also recommendations for screening CXR with reflex to CT and PFTs if there are abnormalities and an echocardiogram.
Ultimately, making the diagnosis of dermatomyositis does not mean that your work in done. Screening for malignancy is considered a must. However, there is debate regarding blind vs. symptom triggered approaches (screening vs. case finding). A recent 2018 article in Medicine looked at a large US cohort of patients with dermatomyositis and examined the prevalence of malignancy and screening practices. Despite limitations, their data may suggest a role for screening beyond history, physical exam and age appropriate cancer screening making an argument for "blind screening" over "triggered screening".