Hi there,
I have very sensitive skin and so does my 3 year old daughter. About 10 years ago or so, out of the blue one summer, I started having the same reaction to sun and sunscreen. After a couple hours outside on a sunny day, whether I used sunscreen and even if I did NOT, I would wake up the next morning with irritated SWOLLEN eye lids and the same itchy, irritation on the inside of my elbows. It seems to be an allergic reaction to the sun. It even happened when I went tanning (which I no longer do anymore). In any case, I found a sunscreen by Neutrogena that has no dyes or perfumes. (I am not at home typing this so I cant remember the exact name, but its in the same white with light blue packaging they use for most all their products.) Whenever I plan to be outside more than 30 minutes during the summer months, I've made sure to massage a light coat of it onto my eyelids and above my lip, as well as the inside of my arms...all the sensitive areas. On my daughter, I put it all over. Whenever I have done this, 99% of the time I've had no reaction. If I use anything else, I break out that night or the next morning. I truly think it was a combination of the sudden onset of a sun allergy and also the fragrances that are in most sunblocks. So if you can't find the Neutrogena sensitive skin sunscreen, try something else that is fragrance free. That's just my story, jsut hoping you can take something from it. GOOD LUCK, I feel for your little one!! P.S. I know that, everyone is different, but I tried 3 Arbonne products on my daughter on the recommendation of a friend and my daughter complained that EACH one made her skin feel "Burning"!!! So if your little one has REALLY sensitive skin, you might want to avoid their stuff. GOOD LUCK!