Allergic reaction to something after cleaning gutters, please help!?

Depends. If allergy you mean skin irritation, be gentle. There is a gamut of ''irritations''. My concern is did you ''gown & glove'' to make a barrier.Did you use anything beyond elbow grease and a little water? Why? Use the most eco-friendly method, ok. I suspect both the leaves & gutters are innocent.Little otc mild cortisone next, do call your physician tomorrow. Otherwise common sense, like mom.