8 months old baby eyelid swollen. This.

My 8 months old baby boy has his upper eyelid swollen on the outer sides on both eyes. Its been there for a week. He had some kind of infection on 16th Nov where both upper and lower eyelids swollen and had small bumps/blisters clustered on upper eyelids.. it settled down after about 10 days. He had similar one at the end of Oct as well. This is the third time it is happening even though there are no visible blisters this time ... For the first two times Ophthalmagist told it is some kind of allergy. We are yet to visit Ophthalmagist this time. We are worried because some kind of infection or allergy is recurring.  He had no such complaints for first 6 months. But in past 2 months he is keep on getting these. He rubs his eyes only in the night while sleeping. On day time he does not run mostly.  There are no discharges in the eyes. No watery eyes. He is feeding normal , taking solids normal, urinating normal, no fever. It doesn't settle for cetirizine as well. Kindly advise on this.