Skin rashes may be an acute (sudden, short lived) problem or they may be a chronic (persistent) symptom. A rash should be considered chronic when it is present for more than 1-2 weeks. In that case it should always be seen by the physician, although this is not urgent.
Acute rashes are a common feature of many viral illnesses and are often preceded or accompanied by other symptoms such as fever, runny nose, cough, vomiting, or diarrhea. They can take many different appearances, but are almost always harmless and need no treatment. Often they itch – this is best treated with an antihistamine such as Benadryl (which is sold without prescription as a cough medicine but which is actually a much better itch medicine – see section on Chicken Pox for dose). If runny nose is also present any decongestant/antihistamine combination will kill both birds with one stone.
Rashes more rarely may signal serious disease. Signs that a rash may be a more urgent problem requiring prompt medical attention include:
bruising or “black & blue” marks (without known trauma)
bright red spots (like tiny “blood blisters” under the skin)
inflamed eyes and/or oral mucous membranes
swollen hands, feet, or glands in the groin & underarm
extensive blistering or breaks in the skin surface
You should call right away if you observe any of the above, or if a child’s other symptoms with the rash (difficulty breathing, signs of dehydration, pain, etc.) warrant in their own right.