What Causes a Rash Over a Child's Entire Body?

Rashes are a common occurrence in children, but they can be a worrisome sight to parents.

Most rashes in children are benign and will go away on their own, but some rashes require close examination and evaluation. Rashes that cover a child’s body are often caused by infections, allergic reactions and illnesses that affect several organ systems.

Infections

Viral illnesses are common causes of rashes in children. These rashes are usually flat and red and not itchy. For example, Parvovirus B19 causes an illness caused fifth disease, in which children have a “slapped cheek” appearance to their face and a red rash that spreads to the arms, legs and chest.

Some other viral rashes that cover a child’s body can also be itchy. The most common one is the varicella virus, which causes chickenpox. This rash starts as flat red bumps that then become crusted over. They usually start on the face and abdomen or back and then spread to the whole body.

Other common viruses that cause rashes have bceom less common because of vaccination. These include measles and rubella or german measles. Bacterial infections can also cause rashes throughout the body. The most worrisome one is the rash of meningococcemia. This infection, caused by the bacteria Neisseria meningitidis, is a flat, purple rash that resembles bruises. This infection can be potentially lethal if not recognized and treated early.

Another bacterium that causes a whole-body rash is group A strep, which causes strep throat or scarlatina. This bacterium causes a raised, bumpy rash often described as “sandpaper” feel to the touch.

Allergies

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Allergic reactions can cause rashes that cover the body of a child. According to the Asthma and Allergy Foundation of America, skin allergies can occur when the skin comes in contact with an allergen, or if you ingest something that you are allergic to.

The rash of an allergic reaction usually is a hive that can become a blister.

Children with eczema, or atopic dermatitis, are sensitive to certain substances, like detergents or other chemicals. The rash is usually a patchy, dry, scaly lesion that can peel or crack.

Other Conditions

Several conditions that affect multiple organs can cause whole-body rashes in children. For example, Kawasaki disease is a condition in which children have five or more days of fever, swollen lymph nodes, pinkeye, swelling of lips or tongue and a rash. This rash can mimic other conditions and its appearance can vary, but it usually covers the whole body.