Asymptomatic livedo reticularis has appeared in ten of 18 female patients with parkinsonism treated with amantadine hydrochloride. Although no serious effects have been seen to date, a livedo reticularis type manifestation has been associated at times with serious collagen disorders such as periarteritis nodosa and lupus erythematosus. Although amantadine has distinct beneficial effects in parkinsonism, long-term use should be viewed with some caution.
Shealy CN, Weeth JB, Mercier D. Livedo Reticularis in Patients With Parkinsonism Receiving Amantadine. JAMA. 1970;212(9):1522–1523. doi:10.1001/jama.1970.03170220076019