Drugs. Various drugs can cause blue skin including minocycline, hydroxychloroquine, imipramine [JAAD 1999;40;159], clofazamine, chlorpromazine (Cutis 2014;93;247), ezogabine (anti-seizure drug [JAMA Derm 2014;150;984]), and amiodarone. Patient on ezogabine, from the FDA.
Argyria. A silver factory worker with implantation of silver leading to argyria. Dermatology Online Journal 19(7)
Mercury. A bluish discoloration may occur after prolonged topical application of mercury-containing compounds to the face or neck.
Neurofibromatosis [AD 118;577]
New blue sheets. Case report of a 10-year-old boy who's skin turned blue which puzzled many for weeks [PD 1991;8;354].
Tache blue seen in pediculosis pubis.
Ochronosis. A bluish gray discoloration of the ears, conjunctiva, and hands may be seen.
Late Onset Dermal Melanosis: An upper back variant
Blue Nevus, Plaque-Type
The nevus of Ito, Ota, the Mongolian spot, and the bilateral nevus of Ota-like macules are grouped under the dermal melanocytoses. Some patients develop blue patches in other places and may simply be called acquired dermal melanocytosis or aberrant Mongolian spots. They may occur on the hand [J Derm 1993;20;561] [Dogica 1977;154;107], extremities [AD 117;103], or face [BJD 1991;124;96].
Nevus of Ito
Nevus of Ota
Phacomatosis pigmentovascularis, bilateral nevus flammeus, and aberrant Mongolian spots on the back. J Dermatol Venereol Leprol. 2010 May-Jun;76(3):307