Might be heat rash. If so, antihistamines (such as Claritin or Zyrtec) may help reduce the redness and itching. It may also be due to the soap, lotion, laundry detergent, etc. ~ it is possible to develop an allergy to something at any time. You might ask if the Allergist or Dermatologist can do skin tests for sensitivity to soaps, etc. Good luck,
Gluten & Sulfite Sensitivity, Many Food/Inhalant/Medication Allergies & Intolerances, Asthma, Gut issues (dysmotility, non-specific inflammation), UCTD (Lupus?), Osteoporosis, Anemia, T- & B-Cell Lymphopenia, malabsorption/malnutrition, Lyme Disease (Igenex Lab IgM WesternBlot positive/CDC negative), etc.
Meds: Pulmicort, Injectable Vitamin B12, Herbs, Nutritional Supplements, Homeopathy.