Pimples. Baby acne occurs in newborns due to hormones passed through placenta. Typically only on the face, with small pimples which resolve without treatment. Eczema is itchy skin on arms, legs and face which mares love at about 6 months or develop more chronic course that flares usually in dry winter weather until age 6.
Different conditions. Baby acne results from mother's hormones circulating in her baby;s body, while eczema is a form of immune hypersensitivity characterized by red, dry flaking patches. Baby acne resolves on it's own, while eczema requires careful skin care with hypoallergenic fragrance free washes, moisturizers and laundry detergents +/- topical steroids.