My 3 year old daughter had a strange spot on her leg that appeared a couple days ago. I applied Sole, a solution of crystal salt and water, several times a day to the spot. Within an hour of the first application, the spot looked way better. I'm still applying it twice a day and the spot is nearly gone. Might be worth a try!
Hi,
It need not necessarily be a bug bite but could be even the sunlight that triggered of this reaction.
Since he already has a history of allergy/Contact dermatitis, he will react even faster to allergens, some of which you may not even recognise.
You can continue with the Benadryl and apply Calamine lotion on the patch. If it begins to show signs of receding then you can relax but if it continues to spread or if he develops a fever then you can get him examined.