Clinical Dermatomyositis in a patient with Common Variable Immunodeficiency: Vigilance for co-exitance of multiple autoimmune conditions

Summary: Background: Patients with an autoimmune disorder are at higher risk of developing other conditions that are autoimmune in nature. We are presenting a patient who is known to have Common variable immunodeficiency (CVID) complicated by recurrent infections and enteropathy who is found to have dermatomyositis (DM) with inflammatory arthritis. The patient is managed by multidisciplinary team that includes gastroenterology, infectious disease, and rheumatology specialists. Case presentation: HPI: This is a 50-year-old female patient with history of CVID who is actively treated with intravenous immunoglobulins (IVIG) for recurrent sinusitis, pneumonia, and gastroenteritis. The patient has significant GI symptoms causing her severe malabsorption and malnutrition that her gastroenterologist decided to treat her with total parenteral nutrition (TPN). The patient presented to the rheumatology clinic for the first time 5 years ago complaining of muscles stiffness, aches, and cramps that had been going for several years. She also complained of peripheral neuropathic pain and significant fatigue. The patient also reported surgical history of mammary silicone implants that had failed twice by rupturing once and leaking another. Physical exam: Significant for intense redness of the face including the forehead, chin, and cheeks with malar distribution and sparing of the nasal labial folds. Rash was also noticed over the chest, thighs and calves. Strength was preserved in the four extremities. Deep tendon reflexes were intact. The lungs were clear. No hepatosplenomegaly or lymphadenopathy were appreciated. Workup: CMP, ANA serology, CK, Aldolase, and myositis panel were ordered in addition to obtaining skin biopsy from the macular skin rash which was sent for histopathological examination. The patient was seen meanwhile by a gastroenterologist who is more familiar with autoimmune conditions and started her on Tacrolimus which improved her GI symptoms only. Labs were wnl except for mild transaminitis (AST/ALT: 41/48). Skin biopsies from the thigh/calve showed no evidence of vasculitis, but small never fiber neuropathy was diagnosed. Skin biopsy from the chest rash has not revealed evidence of immune related changes (e.g. lupus or dermatomyositis). The patient failed therapy with Abatacept, so she was switched to Ubadacitinib. Two weeks later significant improvement was noticed in her GI symptoms along with the skin rash, and polyarthritis. Rifaximin was then added by her gastroenterologist which helped further improve her GI symptoms. Discussion: The patient presentation with photosensitivity, skin rash, muscle cramps/aches/weakness and fatigue raised the suspicion for DM. Response to JAK-I was highly suggestive for co-existing autoimmune/inflammatory conditions. Even though skin biopsy and myositis panel were inconclusive, typical clinical presentation can keep DM among the differential diagnoses. Genetic testing for autoinflammatory conditions can also be of value at this point. Conclusion: Patients with diagnosed autoimmune conditions are at higher risk of developing other autoimmune/inflammatory conditions compared to the general population. Clinicians must keep higher levels of vigilance when these patients present with new unexplained manifestations.