Hello,
Possibility of contact dermatitis or an allergic reaction is there but very less likely. Take some antihistaminic like Benadryl for the itching and apply some calamine lotion on the rashes which helps in soothing the skin. Given the area, milaria is another important possibility.
Also use cotton clothes and change the clothes twice if there is any increased sweating. Try keeping the skin free of sweat as far as possible. If the symptoms still persist then you can apply mild steroid like dermacort.
I hope it helps. Take care and regards.
I know that you said you yourself would need to do an actual diagnosis to identify it but I will add that these clusters are unique to my arms only. What I saw on my chest was just some acne. The bumps/rash you see in the picture are actually starting to itch really badly, at least now that I am worried about them being there. I don't scratch at it but it is definitely annoying and a smaller, similar cluster/rash is forming on my left tricep (4 or so bumps with one in the middle of the formation). It looks much like the one in that picture. I think the room that I am currently sleeping in may have some mold/mildew but at the moment I can't clean the room. That is another issue outside of this discussion but is there a strong possibility that airborne mold/mildew could be the cause, or the mattress that I am sleeping on?
Hello,
I cannot confirm anything without examination but it can be due to folliculitis, pityriasis rosea, acne of the chest and arms or polymorphous light eruption. Pityriasis rosea is a common human skin disease which presents as numerous patches of pink or red oval rash. The rash may be accompanied by low-grade headache, fever, nausea and fatigue and itching.
I would suggest you to consult a dermatologist and get this possibility evaluated as without examination confirmation of a diagnosis is tough. Hope it helps. Take care and please do keep me posted on how you are doing. Warm regards.