Nipple pain after rash may be related to eczema, allergy, breast cancer and so on. 1. Eczema: Mostly seen in nursing mothers, at the onset, rashes often appear on both nipples and areolas, accompanied by itching and pain, and localized skin rashes and erythema may appear. 2. Allergy: when exposed to allergens, the nipple may appear red, swollen, itchy and painful. 3. Breast cancer: malignant disease, which may be accompanied by changes in the nipple and breast, such as itching and pain in the nipple. In addition, some skin diseases may also have similar clinical manifestations. Patients should avoid adverse stimuli in their life, such as eating spicy food, intense scratching, hot water washing and so on, and pay attention to keep local cleanliness to avoid secondary infection. Patients are advised to go to the hospital in time.