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Explore a case study of a patient with contact dermatitis due to cobalt toxicity from metal-on-metal hip implant. Learn about symptoms, diagnosis, treatment, and outcome.
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Mysterious Rash in a Patient with Congenital Hip Dysplasia Erin Hammett Scripps Clinic
Introduction • Cobalt-chromium is a wear-resistant and high strength alloy used in metal on metal (MOM) prosthetic joint implants • Cobalt is a common allergen in contact dermatitis, when exposed to high levels this can lead to toxicity with systemic manifestations
Case • HPI: 45 year old Caucasian female with a past medical history of undifferentiated connective tissue disease and right sided congenital hip dysplasia s/p total hip arthroplasty (THA) in 1993 with revision in 2003 • Chief complaint: Pruritic erythematous rash on upper extremities for several weeks without change in medications or new chemical contacts • Review of systems: Positive for chronic fatigue
Case • Labs: Complete blood count, chemistry panel, C reactive protein and erythrocyte sedimentation rate WNL • Imaging: X Ray R hip: Increased lucency surrounding the femoral stem suggesting particle disease • Skin biopsy: Spongiotic dermatitis with a negative direct immunofluorescence • Further lab testing: Blood cobalt level 10.1 ug/L (ref <3.9 ug/L), serum chromium level 5.7 ug/L (ref <5.0 ug/L)
Case • Diagnosis: Contact dermatitis 2/2 cobalt toxicity • Treatment: Total hip arthroplasty revision • Outcome: Rash resolved within 3 month time period
Discussion • One million patients worldwide have MOM implants, most of which were placed between the years of 2003-2010 • Wear debris complications in MOM implants composed of cobalt-chromium can lead to elevated serum cobalt levels • Cobalt toxicity can result in systemic symptoms such as weakness, fatigue, cognitive decline, peripheral neuropathy, hearing/visual loss, cardiomyopathy, and hypothyroidism
Discussion • The pathophysiology of cobalt toxicity is thought to be due to a delayed type IV hypersensitivity reaction causing aseptic loosening, osteolysis, and cutaneous reactions. The dermatitis component is due to a metal-protein complex transported to skin Langerhans cells causing subsequent T cell activation • Measurement of cobalt/chromium ions and imaging should be performed in patients with MOM implants who present with systemic symptoms or hip pain • Systemic symptoms typically improve with revision arthroplasty
References 1. “Wong C, Nixon R et al. Systemic Allergic Dermatitis Caused by Cobalt and Cobalt Toxicity from a Metal on Metal Hip Replacement.” Contact Dermatitis. Volume 71, No 2, 2014 pp 113-114 2. Graves SE, Rothwell A et al. “A Multinational Assessment of Metal-on-metal Bearings in Hip Replacement.” Journal of Bone and Joint Surgery, American Volume 93, No 3, 2011, pp 43-47