Mycophenolate mofetil as a treatment of steroid dependent Cogan's syndrome in childhood

Cogan's syndrome is a rare chronic inflammatory disorder which typically associates an ophthalmological and vestibulocochlear involvement, with a risk of systemic symptoms in 50-70% of cases. Autoimmune origin has been consolidated by the recent discoveries of Lunardi as a result of the dysregulation of the response of B and T lymphocytes. We report here a pediatric case of Cogan's syndrome, with long term follow-up and complete vestibulocochlear and ophthalmologic examination. During the acute phase, early steroids treatment (prednisone 1mg/kg per day) was effective on ocular lesions and hearing loss. The patient required high steroid doses to maintain remission, suggesting the necessity for steroid sparing immunosuppressive agents. We introduced mycophenolate mofetil (MMF), an immunosuppressive agent mainly used in solid organ transplantation. After steroid withdrawal the patient remained in complete remission on MMF. This is the first report of MMF treatment in Cogan's syndrome. MMF produces a targeted inhibition of the proliferation of B and T lymphocytes, particularly interesting in Cogan's syndrome. Low long term toxicity and overall good tolerance make MMF a new treatment option in steroid dependent Cogan's syndrome.