Purpose: Discovering the cause of early hip prosthesis mobilization is a challenge for the orthopedic surgeon. Infection is one possible cause of early prosthesis failure, but there are other causes that orthopedic surgeons should also consider. Case report: We present the case of a 61-year-old male patient with early hip failure due to cobalt allergy and describe the different diagnosis steps that led to this diagnosis. Discussion: Collaboration between departments was fundamental in order to reach the diagnosis. Revision surgery using components without the allergenic metal and using different surface bearing materials (ceramic-ceramic) gave satisfactory results.