Vitamin B1 (Thiamine)

Vitamin B1 or thiamine was the first water-soluble vitamin to be isolated. Thiamine deficiency leads to the onset of beri-beri and Wernicke encephalopathy, often associated with Korsakoff psicosis, above all, in chronic alcohol addicted patients. The necessity to administer quickly intravenous thiamine hydrochloride to restore blood thiamine level caused in some patients the onset of a severe immediate type reaction like anaphylactic shock, sometimes with lethal outcomes. The pathomechanism of hypersensitivity reaction seems to be genuinely IgE mediated and thiamine hydrochloride, that is the synthetic pharmaceutical form of thiamine, probably is a sensitizing hapten able to conjugate with azoproteins. Furthermore, patients with immediate-type hypersensitivity to parenteral thiamine may tolerate that vitamin when assumed orally. On the contrary, few cases of allergic contact dermatitis to thiamine are reported in literature, mainly following an occupational exposure and the oral intake of vitamin B1 is always associated with a flare-up of dermatitis.

Keywords: Allergic Contact Dermatitis, Anaphylaxis, Angioedema, Delayedtype Reaction, IgE, Immediate-type Reaction, Skin Tests, Thiamine, Thiamine Hydrochloride, Thiamine Mononitrate, Urticaria, Vitamin B1.