Mycobacterium chelonae infection under adalimumab therapy for spondylarthritis

Tumour necrosis factor (TNF)-alpha antagonists have been prescribed increasingly over the past few years to manage various inflammatory diseases. This widespread use was quickly followed by the heightened frequency of opportunistic mycobacterial infections including environmental non-tuberculous mycobacterial infections (ENTM). We describe a 66-year-old man taking adalimumab for spondyloarthropathy who developed an inflammatory infiltration in his right index finger. A non-necrotising granuloma with epitheloid and giant cells in the dermis and eosinophilic acid-fast bacilli, identified by using Ziehl-Neelsen staining suggested a mycobacterial infection. Cultures for mycobacteria grew positive on Loewenstein-Jensen medium and molecular identification confirmed M. chelonae infection. The outcome was favourable after five months of clarythromycin. In this context of more frequent ENTM infections, chronic non-specific cutaneous lesions of the extremities should evoke systematically cutaneous ENTM infections. Skin biopsy with histological examination and oriented microbiological cultures and molecular identification are mandatory to confirm the diagnosis.