Food allergy?

Nicole
My son had strawberries a couple times at daycare today. He's had them before too. Anyway he developed a small rash on the back of his leg, where the diaper ruffles meet his leg, not the line but but the ruffles. And this evening, a good 4 hours after strawberries he spit up with a little tinge of pink, very small amount. Could it be an allergy?