It could be chafing from the socks and sweaty feet take the socks off and see it the rash appears with out them, it may also be the material its made from.What about ant bites ..does the rash itch or hurt?
My kids will get a raised red rash when they play in grass. Not every time for sure but sometimes. It disappears on its own pretty quickly. It's never spread but localized to the areas that were in grass. Your son may just have sensitive skin???? One of my boys does as well. I try not to make a big deal out of and kind of ignore it and it does seem to go away very fast.
Now, when my son was really tiny like your son's age-------- he would eat pinapple pieces and the juice would drip down and he'd get a red rash on his wrists and forearm. I asked the doctor about it and she wasn't sure if that was right or not but I made a big enough deal about it that my son swears he 's allergic to pinapple. He' s not. He's now 8 and eats it all the time and has had no skin issues. I'm not sure what was going on back then. BUT, my point is that I made a big deal about it to the point that he thought he has an allergy which he doesn't. So, keep all your concern on the down low.
Wishing you lots of luck. 16 month olds are very fun and VERY busy!
My 20 month old has the exact same problem the Doctor has told me to use Hydro Cortisone cream 2 x a day, because he too thought it was an allergy to the elastic. But I notice tonight the rash appeared above the sock and imeadately after I took off the socks not before they were removed. It takes several days for the rash and rough skin to mend after it appears. Today was the first time she has wore socks in a week. She has played outside in grass with her sandals and nothing. He also said it can't be an allergy to laundry soap or it would develop else where. I am hoping to find the cause soon because it looks irrating and bothersome.
wonder if its the material the socks are mad of, does she wear those plastic sandals and its known they can give a rash
Have you ruled out heat rash??? I don't know how itchy it is but heat rash involves blocked sweat glands and it can definately form into a raised rash. Another possibility is discoid eczema. Unexplained dermatitis is a real thing as well. I have 'something' going on with one of my fingers. It will flair up into an itchy, very small raised rash, and then I scratch and the skin gets shiny and it peals. It does this a couple of times a year and is ONLY on my pinkie. ????? My doctor says thingss like this happens and I just treat the symptoms when there is a flare up.
I would consider the cortisone cream. My son has something going on with two of his toes where he says they itch and they become red with a patch on them. This has a name my doctor told me but it escapes me now as this began when he was tiny and he is now 7. He has a cortisone cream that i began putting on him as a little toddler. Now he will just tell me when it itches and we put it on. Those creams are not typically dangerous and can really help. Because what you DON'T want is a secondary infection from itching.