Summarize the following:
Eczema and butterfly rash have different characteristics which will help you distinguish between the two:  Eczema is a condition in which patches of skin become red, itchy, dry, cracked and sore. It can occur anywhere on your body but it is most common in areas where your skin forms creases, such as your hands and fingers, the insides of your elbows, the backs of your knees, and your face and scalp. As it heals your skin may be temporarily discolored. Butterfly rash is named this because it often forms the shape of a butterfly, running from the bridge of the nose to both cheeks. It is red, raised, and may be scaly, itchy or painful. The rash may also appear on other areas of the face or the wrists and hands. However, it usually does not cover the nasal folds. Your nasal folds are the areas under the sides of your nose. Eczema and butterfly rash have different triggers. Understanding what brings on each type of rash may help you to differentiate them.  Eczema is often triggered by irritants like soaps, detergents, or other chemicals, environmental influences like cold, dry weather, or humidity, allergens like dust mites, pet fur, pollen or mold, food allergies such as milk, eggs, peanuts, soy or wheat, allergies to fabrics like wool or synthetics, or hormonal changes in women during their cycle or during pregnancy. The butterfly rash may appear without an obvious trigger or after you are exposed to sunlight. If this is the case, you should see a physician, as this may be a sign of lupus. Butterfly rash is itself a symptom of lupus, while eczema is not a symptom of an underlying condition.  People with eczema often also have allergies, hay fever, asthma, or a family member with these conditions. People with butterfly rash generally have other symptoms of lupus which may flare up at times. These symptoms include exhaustion, fever, sensitivity to the sun, chest pain, headaches, confusion, memory loss, difficulty breathing, dry eyes, joint pain and swelling, or fingers and toes that turn white or blue in reaction to stress or cold.

Summary:
Look at the rash. Evaluate what triggers the rash. Consider whether you have other symptoms.