An exanthem is a rash that covers most or all of the body. It is a rare complication in adults, but fairly common in infants and young children. Many different conditions can trigger an exanthem, including viral infections, bacterial infections, adverse drug reactions, and abnormal immune system responses. The presentation and symptoms of the rash depend on the underlying cause, but many exanthems cause itchy bumps or flat, spotty patches of red skin. Rashes typically go away once the cause is treated or the virus runs its course, but a pediatrician may suggest special lotions or topical ointments to ease symptoms in the meantime.
Common causes of an exanthem include the viral infections chickenpox, measles, and influenza. Nearly any widespread bacterial infection can lead to a serious rash in a very young infant, including staphylococcus and streptococcus. A child might also suffer an allergic reaction to a topical or oral medication or a particular kind of lotion. Occasionally, a major autoimmune disorder is responsible for exanthems. In some cases, a rash may even appear without any recognizable cause.
Most exanthems are preceded by other symptoms of the underlying illness. Viral infections, for instance, often cause fever, fatigue, joint and muscle aches, and loss of appetite before rashes appear. An infant may be highly irritable or especially lethargic as an illness sets in. When an exanthem does develop, it often covers nearly all of the child's skin. Redness and bumps are usually more concentrated on the torso, buttocks, arms, and legs than on the hands, feet, and face.
It is important to visit a pediatrician whenever a body-wide exanthem and other symptoms develop to determine the best course of treatment. A doctor can usually determine the cause based on the child's physical symptoms. Blood or skin tissue samples may need to be collected and tested to confirm the diagnosis in some cases.
Many childhood viral illnesses do not respond well to medical treatment. Doctors simply encourage parents to ensure their children get plenty of rest and fluids until infections clear up. Oral antibiotics are usually effective at speeding the healing phase of a bacterial infection, and stopping or changing medications ends drug-related reactions quickly. If the exanthem is itchy and irritating, a pediatrician can provide a topical antihistamine ointment or recommend an over-the-counter calamine lotion. Most exanthems disappear in about two weeks without causing permanent skin damage or lingering health problems.