Sarcoid-like immune reaction following COVID-19 infection presenting with COVID toes and dactylitis

ABSTRACT

A 21-year-old woman presented with a 5-month history of swollen, painful, purple discolouration of her toes and fingers, which began 6 weeks after COVID-19 infection. This was refractory to ibuprofen and clobetasol 0.05% w/w ointment. She reported no other associated symptoms. On examination she had erythematous mottling of the tips of the toes and nail folds of the right foot and sausage-shaped deformities of the left second and fourth toes, consistent with dactylitis. Her blood work-up for COVID toes revealed a raised serum angiotensin- converting enzyme (ACE) level (64 U L-1) with no other abnormalities. Her chest X-ray was unremarkable. Plain radiographs of the feet showed soft tissue swelling and lacelike bony appearances with discrete areas of lucency, particularly affecting the middle phalanx of the left second toe. This pattern has been described in sarcoid arthropathy. Magnetic resonance imaging of the left foot demonstrated features of inflammatory arthropathy, including subarticular bone marrow oedema, periarticular soft tissue oedema and flexor tendon tenosynovitis. The findings were consistent with COVID toes;however, some features of the dactylitis extended beyond the expected presentation of a vascular manifestation of COVID-19. She displayed overlap features seen in sarcoid-related pathologies, including raised ACE levels and a lace-like bony appearance. We believe this to be a sarcoid-like immune reaction to COVID-19 presenting with COVID toes and dactylitis. A sarcoid-like immune reaction to COVID-19 with granulomatous skin lesions rather than dactylitis has been reported. Viral infections are a documented trigger for sarcoid- like immune reactions. This case suggests that COVID-19 can trigger sarcoid-like immune reactions, albeit with a more discrete presentation.