Use PABA-free sunscreens. Eczema sufferers will find this ingredient can cause flare ups. Make sure to carefully review ingredients, even in PABA-free products. If necessary, you can make an appointment with your doctor to ask about prescription sunscreen. Excessive sweat kept on the body can cause eczema flare ups. Getting overheated and sweating a lot can aggravate eczema. If you like to stay active, be sure you cool down when you're done with your activity. A shower can help here.