Healthline, MedicineNet and WebMD feature images of stomach rashes on their websites. Causes of rashes on the stomach include contact dermatitis, psoriasis, eczema, impetigo and certain autoimmune diseases, according to Healthgrades. Rashes typically cause redness and swelling, and may result in flaky, scaly or pus-filled bumps,
Allergies to foods, such as peanuts, avocados, strawberries or shellfish, can trigger serious reactions and cause stomach rashes, as can allergies to medications and certain chemical products, states Healthgrades. Scarlet fever sometimes starts with a rash on the stomach that then spreads to other areas of the body; Kawasaki disease, a rare childhood disorder, also sometimes begins as a rash on the stomach.