title: Crusted Norwegian scabies, an opportunistic infection, with tocilizumab in rheumatoid arthritis.
abstract: BACKGROUND
  Crusted Norwegian scabies is an extremely rare hyperkeratotic variant of scabies infestation. We report herein a case of crusted scabies in a woman with severe rheumatoid arthritis (RA) treated by tocilizumab (TCZ), a monoclonal antibody blocking the interleukin-6 receptor.
  
  
  METHODS
  An 80-year-old female with severe RA developed erythroderma followed by hyperkeratosis, widespread scaling over the trunk, arms, hands and limbs, and crusted lesions on her scalp. She was on TCZ (8 mg/kg per month) with prednisone (20 mg/d). Several hypotheses were evoked (i.e., vasculitis, psoriasis or paraneoplasic syndrome) but a microscopic examination of the skin surprisingly demonstrated numerous scabies mites and eggs leading to the diagnosis of crusted (Norwegian) scabies. After repeated use of ivermectin and application of topical piperonyl butoxide cream, scabies disappeared. However, there had been outbreak of scabies among two individuals in the staff and two patients. TCZ was stopped after four infusions because of a severe infectious pneumonia and failure.
  
  
  CONCLUSIONS
  Crusted scabies should be evoked in case of pruritus or erythroderma occurring under TCZ therapy and it may be explained by the interleukin-6 blockade.
authors: Department of Rheumatology, AP-HP, Saint-Antoine Hospital, Pierre-et-Marie-Curie University, 184, rue du Faubourg-Saint-Antoine, 75012 Paris, France.
authors: Khadija
authors: K
authors: Baccouche
authors: Jérémie
authors: J
authors: Sellam
authors: Sarah
authors: S
authors: Guegan
authors: Sélim
authors: S
authors: Aractingi
authors: Francis
authors: F
authors: Berenbaum
mesh_terms: D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized / Q000009:adverse effects*; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D007559:Ivermectin / Q000627:therapeutic use; D009894:Opportunistic Infections / Q000139:chemically induced* / Q000175:diagnosis / Q000276:immunology; D011241:Prednisone / Q000627:therapeutic use; D012532:Scabies / Q000139:chemically induced* / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology; D000093242:Interleukin-6 Inhibitors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D061067:Antibodies, Monoclonal, Humanized; D007559:Ivermectin; D011241:Prednisone; D000093242:Interleukin-6 Inhibitors; C502936:tocilizumab