context: A newborn's skin is prone to rashes of all sorts. Fortunately, most of these rashes are harmless and go away on their own. Pink pimples ('neonatal acne') are sometimes thought to be caused by exposure in the womb to maternal hormones. No treatment is needed, just time. They can last for weeks or even months on a baby's skin. Erythema toxicum is another common newborn rash. It looks like red blotches with ill-defined borders that are slightly raised, and may have a small white or yellow dot in the center. Its cause is unknown, and it resolves without treatment after a few days or weeks. Dry, peeling skin can be seen in almost all normal babies, but is especially noticeable in babies born a little late. The underlying skin is perfectly normal, soft, and moist. Little white bumps on the nose and face (milia) are caused by blocked oil glands. When a baby's oil glands enlarge and open up in a few days or weeks, the white bumps disappear. Salmon patches (called a ''stork bite'' at the back of the neck or an ''angel's kiss'' between the eyes) are simple nests of blood vessels (probably caused by maternal hormones) that fade on their own after a few weeks or months. Occasionally, stork bites never go away. Jaundice is a yellow coloration on baby's skin and eyes. It is caused by an excess of bilirubin (a breakdown product of red blood cells). If the bilirubin level becomes sufficiently high, blue or white lights may be focused on the baby's skin to lower the level, because excess bilirubin can sometimes pose a health hazard. Mongolian spots are very common in any part of the body of dark-skinned babies. They are flat, gray-blue in color (almost looking like a bruise), and can be small or large. They are caused by some pigment that didn't make it to the top layer when baby's skin was being formed. They are harmless and usually fade away by school age. New rashes may appear in babies after a few days, weeks, or even months. Cradle cap (seborrhea) often shows up at 1-2 months of age. Greasy, yellowish crusts appear on the scalp and may include a red, irritating rash on the face, behind the ears, on the neck, and even in the armpits. Your doctor will tell you how to best treat this common condition, depending on your baby's symptoms. Eczema is red, itchy patches on the skin, often seen on the baby's chest, arms, legs, face, elbows, and behind the knees. It is caused by dry, sensitive skin, and sometimes allergies (although it can be difficult at this age to know what the trigger might be). Your doctor can determine if the rash looks like eczema and prescribe the appropriate treatment. In general, treatment consists of: Using a very gentle soap Using a gentle detergent and no fabric softener in baby's laundry Using skin moisturizers Applying a steroid cream (like hydrocortisone or even a stronger one) if the eczema won't go away Prickly heat looks like small red bumps, mostly on areas of your baby's body that tend to overheat and sweat, like the neck, diaper area, and armpits. The treatment is to try to keep the area dry and avoid overheating by dressing him in loose-fitting clothing. A fungal infection(candidiasis) can show up in different ways on your baby. On the tongue, it is called thrush and looks like dried milk, which, unlike milk, cannot be scraped off. In the diaper area, candidiasis looks like an intense red rash, often with smaller bumps around the edges. A fungal infection loves moist, dark areas, so you'll find redness due to it in the creases of the thighs. Candidiasis is treated with antifungal oral gel or liquid medicine (for oral thrush) or antifungal cream (for the diaper area), or both. In the first few months of a baby's life, any rash associated with other symptoms (such as fever, poor feeding, lethargy, or cough) needs to be evaluated by a doctor as soon as possible. While most rashes are not serious, a few need very close attention: Fluid-filled blisters (especially ones with opaque, yellowish fluid) can indicate a serious infection, like a bacterial infection or herpes. Small red or purplish dots over the body (''petechiae'') can be caused by a viral infection or a potentially very serious bacterial infection. These will not lighten with pressure. Any infant with possible petechiae should be evaluated by a doctor immediately.