Atypical cutaneous manifestations in hyperimmunoglobulin D syndrome: A case report

Hyperimmunoglobulin D syndrome (HIDS) is a rare autosomal recessive autoinflammatory disorder caused by mutations in the mevalonate kinase (MVK)gene. It is characterized by recurrent fever episodes, abdominal pain, elevated serum IgD levels, and systemic inflammation. We report a 5-year-old boy presenting with recurrent fever, abdominal pain, diarrhea, and hyperpigmented skin lesions. Physical examination revealed abdominal distension and multiple café-au-lait like spots on the lower extremities, with no lymphadenopathy or organomegaly. Whole-exome sequencing revealed a homozygous missense pathogenic variant (c.1129G>A; p.Val377Ile) in MVK gene. Abdominal CT revealed colonic wall thickening with mucosal hyperenhancement. However, the lower GI endoscopy was unremarkable. Skin biopsy was consistent with café-au-lait spots. Despite the inadequate response to colchicine and anakinra, the patient showed significant clinical improvement with canakinumab. This case underscores the diagnostic complexity of HIDS and suggests a potential novel association with café-au-lait macules. Early genetic testing is crucial for timely diagnosis and targeted therapy.