A rash is an area of skin irritation. It can be localized to small area of the skin or cover the entire body. In children, generalized rashes are very common, but are also concerning as they can indicate a serious medical condition, especially if the rash is accompanied by fever, headache, sore throat or listlessness.
Viral Infections
Viral infections are a common cause of generalized rashes, or exanthems, in children. Most of these infections are not serious and only require treatment for symptoms like fever and dehydration. There are several viruses that cause similar rashes, making their identification difficult, while other exhibit characteristic rashes. For example, the typical rash of erythema infectiosum, or fifths disease, is a lacy rash on the arms and legs and a "slapped cheek" appearance to the face. According to the Merck Manuals, fifth disease, caused by parvovirus B19, occurs most often during the spring, and causes a mild illness with fever and the rash. Another common virus that causes a generalized rash is the varicella virus, the source of chickenpox. The rash of chickenpox starts as small flat red spots that change into clear vesicles. These itchy blisters eventually crust over, turning into ulcers that eventually heal up on their own.
Bacterial Infections
Just like viruses, bacterial infections can cause generalized rashes in children. The difference is that bacterial infections can be potentially life threatening. For example, meningococcemia, a dangerous infection by the Neisseria meningitidis bacteria, can result in death if not adequately treated. Meningococcemia causes a vasculitis, or an inflammation of the blood vessels, which manifests itself as areas of bleeding under the skin. This results in a rash called petechia, which according to MedlinePlus, are pinpoint red spots that can coalesce into larger purple-colored spots and patches called purpura. Another common bacterial infection, strep throat, can cause a generalized rash, described as a raised, fine pinpoint rash that resembles sandpaper on contact.
Allergic Reactions
Allergic or anaphylactic reactions can cause a generalized rash, known as urticaria or hives. Hives appear as raised red itchy welts of different sizes. They appear to spread or move from one area of the body to another. According to the Mayo Clinic, after exposure to an allergen, such as medicines, foods or pollen, the body responds by releasing massive amounts of histamine into the blood stream. Histamine causes separation of some of the skin cells, resulting in hives. Antihistamine medicines, such as diphenhydramine or Bendaryl, are part of the treatment for hives.
