Quote: Peanut allergy is one of the worst - I know people that have it so bad, for them it is literally life-threatening. But if you have one food allergy, you can develop more (by taking appropriate measures, you can develop tolerance for some things to which you were previously reactive, too - but that's the domain of allergists, not an anonymous forum dweller).
My mother developed Lyme's disease from a tick bite. I second (or is it third?) the advice to get diagnosed and treated - it's nothing to mess about with!