P0889 - Juvenile Dermatomyositis: A Classic Presentation in a 3-year-old African American Male

Introduction:
Juvenile dermatomyositis is a rare disease with an incidence of 3.2 out of 1 million children in the United States per year. Females are two times more likely to be affected, and white children are predominantly affected when studying populations in North America. Though the average age of presentation is 7, 25% of children are under the age of 4 when symptoms first manifest, emphasizing the importance of maintaining a high clinical suspicion when patients first present with classic symptoms.

Case Description:
A 3-year-old African American male with a past medical history of eczema and asthma presented to our facility with a 2-month history of progressively worsening proximal lower extremity muscle weakness and pain as well as a new rash on his face and chest. Physical examination was remarkable for eczematous plaques on the flexor surfaces of his elbows and knees bilaterally and Gottron’s papules and hypopigmented patches on his forehead, chest and back (“Shawl sign”), and around his eyes. His cranial nerves and sensation appeared in tact, and strength was noted to be 4-5/5 in all extremities when he was lying down. Upon gait testing, he walked with his hips in external rotation with subsequent out-toeing of his feet bilaterally, and cried until he was picked up by his mother, no longer bearing weight on his lower extremities. An extensive evaluation revealed an elevated erythrocyte sedimentation rate, creatinine kinase, aldolase, and lactate dehydrogenase along with myositis on an MRI of his C-spine, consistent with the diagnosis of juvenile dermatomyositis.
Treatment was initiated with high dose IV methylprednisolone at 30mg/kg/d every 6 hours with marked clinical improvement. Our patient was subsequently transitioned to high dose oral prednisolone at 2mg/kg/d divided twice daily for 6 weeks with concurrent use of subcutaneous methotrexate 15mg/m2 once every 7 days and daily folic acid supplementation. He was discharged home with continuing improvement in his motor strength noted, and with referrals for continued physical and occupational therapy as well as outpatient rheumatology follow up.

Discussion:
Juvenile dermatomyositis is a rare disease that requires a high index of suspicion for diagnosis to be made. The mean age at symptom onset and diagnosis is 6.1 and 6.6 years, respectively. Our patient was 3 years old at the time of both symptom manifestation and diagnosis, earlier than the average age reported, adding to the limited number of case reports on patients presenting at this early age.

Conclusion:
This case illustrates the classic presentation of a rare disorder in an African American male at a younger-than-average age of symptom presentation and diagnosis. It is important to recognize these signs to aide in earlier diagnosis and treatment, potentially preventing morbidity as the disease progresses.