Last night I suddenly felt stingy sensation on bilateral hips. Observed large red welts on both hips and small welts seen behind left knee. Never seen before. This a.m. hip welts were gone, but larger welts observed behind knees. Took (2) 25mg benadryl and itch subsided... 22 hours since welts were first seen, I am now noting more smaller welts in increasing numbers on inside of legs travelling toward knees. Circular in varied sizes. Only changes recently were typhoid fever shot taken for upcoming mission trip to Oaxaca, Mexico 1.5 weeks ago. Took oral version of this 5 years ago. No side effects then. I work as hospice nurse and am exposed to large variety of people and medical issues. Any suggestions?