Itchy rashes on the chest and body, with small red spots on the face and neck, are often due to an allergy, heat rash, or skin irritation from sweat or products. Keep your skin clean and dry, wear loose cotton clothes, and avoid heat, dust, and any new creams or soaps that may trigger it. Simple, soothing measures like a cool compress and natural calming applications may help, but avoid self-use of strong treatments. If it does not improve or keeps spreading, consult your doctor so the exact cause can be confirmed and safe treatment can be advised.