Histamines affect a broad spectrum of body systems. One time I was really stressed about work, went to bed and started itching unbearably and had welts. Apparen

Histamines affect a broad spectrum of body systems. One time I was really stressed about work, went to bed and started itching unbearably and had welts. Apparently I had broken out into hives, which I didn't recognize at first, then I took an antihistamine and within half an hour everything was back to normal.