Without examination it is very difficult to confirm a diagnosis, but the symptoms are suggestive of heat rash
, contact dermatitis or sweat dermatitis. Prickly heat
(miliaria) is an itchy skin rash caused by trapped sweat. It tends to occur on areas of the body where skin touches skin, such as under the breasts, on the inner thighs, and under the arms. Tiny red spots with itching and pricking sensation are the characteristic appearance of this rash.