A rash is a change in the color or texture of the skin. A skin rash can be flat, bumpy, scaly, red, skin-colored, or slightly lighter or darker than skin color.

Most bumps and blotches on a newborn baby are harmless and clear up by themselves.

By far the most common skin problem in infants is diaper rash. Diaper rash is an irritation of the skin caused by dampness, urine, or feces. Most babies who wear diapers will have some type of diaper rash.

However, there are other skin disorders that can cause rashes. These are usually not serious unless accompanied by other symptoms.

• Diaper rash (rash in the diaper area) is a skin irritation caused by prolonged dampness and the interaction of urine and feces with the skin.
• Yeast diaper rash is caused by a type of yeast called candida, which also causes thrush in the mouth. The rash looks different from a regular diaper rash. It is very red, and there are usually small red bumps on the outer edges of the rash. This rash requires treatment with medication.
• Heat rash or prickly heat is caused by the blockage of the pores that lead to the sweat glands. It is most common in very young children but can occur at any age, particularly in hot and humid weather. An infant does not sweat. The sweat is held within the skin and forms little red bumps or occasionally small blisters.
• Erythema toxicum can cause flat red splotches (usually with a white, pimple-like bump in the middle) that appear in up to half of all babies. This rash rarely appears after 5 days of age, is usually gone in 7 - 14 days, and is nothing to worry about.
• Baby acne is caused by exposure to the mother's hormones. Red bumps, sometimes with white dots in the center, may be seen on a newborn's face. Acne usually occurs between 2 and 4 weeks of age, but may appear up to 4 months after birth and can last for 12 - 18 months.
• Cradle cap (seborrheic dermatitis) causes greasy, scaling, crusty patches on the scalp that appear in a baby's first 3 months. It usually goes away by itself, but some cases may require treatment with medication.
• Hives are red welts that appear to move around on the body. For example, if you drew a circle to mark one of the welts, a few hours later that circle would not have a welt in it, but there would be welts on other parts of the body. They differ in size and shape. Hives may last for a few weeks. The cause is uncertain.
• Eczema is a condition of the skin in which areas are dry, scaly, red (or darker than normal skin color), and itchy. When it goes on for a long time the areas become thickened. It is often associated with asthma and allergies, although it can often occur without either of these. Eczema often runs in families.