Allergy or not?

Nurse Lisa

So I have a lot of food allergies myself. So far we haven't noticed any allergies with my 1 year old daughter. This morning about half hour after her bottle of formula I noticed around 10-15 hives around her armpit and the surrounding area. Do you think after all this time she's suddenly developed an allergy to milk or her formula? She's been on this formula since she was 6 months old. The hives cleared up after about an hour except for a few lingering around. What do you think?