Does this look like an allergic reaction?

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This just came up on my 8 month old's arm, where her arm had been resting on her high chair tray. She was eating tomatoes and rice cakes with hummus, all of which she's eaten before. Could it be an allergy from where her arm was resting in the tomato juices? What do I do now if it is a reaction? Thanks.

Oh and in case the photo isn't clear the skin has gone red and there are some raised white marks. She's not bothered by it!

tomato have a fair bit of histamine in. so this is a contact reaction. I take it no ill effects from eating them?

My dd had a similar reaction to raw tomato juice as a baby. Her hands and legs swelled up alarmingly on contact. She was fine with cooked tomatoes. We avoided raw tomatoes for about a year and when we tried it again, she didn't have the same reaction. Aged 7, she won't eat raw tomatoes as they make her mouth hurt. She had similar, but not as alarming, reactions to melon and pineapple. She now eats pineapple without any problem.

She also has a diagnosed severe peanut allergy. The weird reaction to tomatoes was the first sign that there was
an issue with allergies. Sorry.