60 year-old female with painless non-pruritic rash

dermatomyositis

Key Point:

Patients with dermatomyositis present with the gradual onset of bilateral proximal muscle weakness as well as skin rashes.

Explanation:

The most likely etiology of this patient's symptoms is dermatomyositis.

The images show the heliotrope rash as well as Gottron's papules which are classically associated with dermatomyositis. The heliotrope rash is an erythematous rash found over the eyelids. Gottron's papules are erythematous papules that are found on the extensor surface of the metacarpophalangeal and interphalangeal joints and may have a scaly appearance.

The next step in the management of this condition would be to initiate therapy with a systemic steroid such as prednisone.

It is also important to recognize that dermatomyositis has been associated with malignancy so the patient should receive age-appropriate screening tests to exclude underlying malignancy.

While patients with polymyositis may have symmetric bilateral proximal muscle weakness that develops over years, polymyositis is typically not associated with any rashes. Patients with inclusion body myositis present with the gradual onset of asymmetric and distal muscle weakness that usually occurs over several years. Patients with polymyalgia rheumatic usually present with acute/subacute onset of pain and stiffness of bilateral extremity proximal muscles with normal strength on neurologic exam.

References:

Miller M. "Diagnosis and differential diagnosis of dermatomyositis and polymyositis in adults." . Topic 15683, Version 8.0. Revised Sept 28, 2016. Accessed December 20, 2017.

Miller M, Vluegels R. "Clinical Manifestations of Dermatomyositis and Polymyositis in Adults." . Topic 5159, Version 17.0. Revised January 30, 2017. Accessed December 20, 2017.

Miller M, Lloyd T. "Clinical Manifestations and Diagnosis of Inclusion Body Myositis*."* . Topic 5163, Version 18.0. Revised March 7, 2016. Accessed December 20, 2017.

“What Is Dermatomyositis?” Myositis Support and Understanding.