MINNEAPOLIS — Severe nutritional deficiencies can mimic rheumatic disease and result in delayed diagnosis and unnecessary workups, as illustrated in a series of four cases presented at the American College of Rheumatology’s Pediatric Rheumatology Symposium (PRSYM) 2026.

“A detailed dietary history and comprehensive nutritional assessment are critical, particularly in at-risk individuals,” Helina Maharjan, MBBS, a rheumatology fellow at Albany Med Health System inAlbany, New York, and her colleagues concluded. “Early recognition can prevent misdiagnosis, invasive testing, unnecessary immunosuppression, and treatment delay.”

Jay Mehta, MD, MS, an attending rheumatologist and associate program director of the Pediatrics Residency Program at Children’s Hospital of Philadelphia, Philadelphia, was not involved in the research and said he found it a very interesting case series that “highlights the need to consider alternative explanations when the clinical course is unexpected or there is a history of dietary differences.”

The researchers reviewed patient records of children and young adults in the Albany Med Health System who had been diagnosed with nutritional deficiency that mimicked rheumatic disease. They identified three children and one young adult.

In the first case, a 9-year-old girl presented with left ankle pain, swelling, and bruising for 3 days; a small effusion in her left knee; and ankle swelling with a large ecchymosis and calf tenderness. She had splinter hemorrhage and palatal petechiae, and a history of blood transfusion 2 years earlier for unexplained severe anemia.

A bilateral ultrasound of her knees revealed a small amount of fluid adjacent to her femurs, and an MRI of her lower extremities revealed soft tissue inflammation, symmetric myositis, and metaphyseal marrow changes in the long bones.

These symptoms with lab values mimicked vasculitis, lupus, inflammatory bowel disease, and chronic nonbacterial osteomyelitis, but undetectable vitamin K levels and vitamin C levels below 0.1 mg/dL indicated a diagnosis of scurvy and vitamin K deficiency. Her risk factors had been a restrictive diet of crackers, noodles, and potato chips, and her symptoms rapidly resolved with vitamin C and K supplements, which were followed by dietary rehabilitation and behavioral counseling.

The second case was a 7-year-old boy who presented with intermittent diarrhea and a low-grade fever. He had had ankle pain and knee pain and swelling for 4 weeks, and he had perifollicular petechial lesions on his arms and legs. An x-ray of his knees and ankles revealed asymmetric right knee swelling and suprapatellar effusion, and bilateral metaphyseal lucency suggested leukemia or rickets.

Potential mimics included immunoglobulin (Ig)A vasculitis (Henoch-Schönlein purpura), juvenile idiopathic arthritis, or leukemia, but he had undetectable vitamin C and low vitamin A and D and was ultimately diagnosed with scurvy, rickets, and vitamin A deficiency. He had severe autism with a restrictive dietary habit, and his symptoms quickly improved with vitamin C and K supplementation, followed by nutritional support and behavioral counseling.

The third case was a 21-year-old man who initially presented with a rash on both legs and inner thighs and recurrent nausea, vomiting, and bloody stool for the past year, resulting in weight loss of 70 lb. Several months after his initial presentation, he had developed gingival erythema and dense, red perifollicular purpura, papules, and macules in his lower extremities that mimicked leukocytoclastic vasculitis.

He had swelling in his feet, ankle, and shin and a tender left gluteal hematoma, but x-rays of his ankle and feet were normal, as were a magnetic resonance enterography scan, esophagogastroduodenoscopy, and colonoscopy. His undetectable vitamin C levels led to a diagnosis of scurvy. He had avoidant restrictive food intake disorder, and high-dose vitamin C supplementation resolved the rash and swelling. Follow-up included referral to a multidisciplinary eating disorder clinic.

The fourth case was a 13-year-old boy who had experienced progressive vision loss over the previous 3 weeks. He had a low-grade fever, vomiting, agitation, and echolalia, and his balance was often off, resulting in frequent falls and bumping into things. Redness and a white discharge in the eyes had not resolved with cefdinir.

His cheeks had acneiform lesions, and his extremities had hyperpigmented papules. An ophthalmologic exam revealed bilateral interstitial keratitis and optic disc edema in the right eye but no uveitis. A brain MRI showed pachymeningeal enhancement. His family history included a cousin with Behçet disease.

The differential included lupus, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, Behçet disease, sarcoidosis, IgG4-related disease, and idiopathic hypertrophic pachymeningitis, but his labs were negative for antinuclear antibodies, ANCA, rheumatoid factor, and IgG subclasses. He also had normal angiotensin-converting enzyme levels and normal cerebrospinal fluid but elevated lysozyme (11.2 ug/mL). He also had normal ranges for bilirubin (1.2 mg/dL), c-reactive protein (2.8 mg/L), and alanine aminotransferase (42 U/L).

He was initially prescribed intravenous steroids with an oral taper, but he was readmitted 3 weeks later with worsening symptoms. An evaluation of normocytic anemia led to discovery of undetectable vitamin B12 levels and low vitamin A and D levels. He had severe autism, and his restrictive dietary habit had resulted in vitamin A, D, and B12 deficiency. Nutritional repletion led to a rapid neurologic recovery back to baseline and normal labs, but his vision loss persisted. A repeat brain MRI was normal.

The authors noted that “micronutrient deficiencies can lead to protean clinical manifestations and may mimic autoimmune or auto-inflammatory diseases, contributing to misdiagnosis, delays in treatment, and even unnecessary immunosuppression.” Those particularly at risk include people with restrictive eating behaviors, developmental disorders, or malabsorption.

No external funding or disclosures were noted. Mehta had no disclosures.

Tara Haelle is a science/health journalist based in Dallas.