How Do I Recognize a Skin Rash from an Allergic Reaction?

Determining whether a skin rash is simply a rash or an allergic reaction can be difficult, especially because a skin rash sometimes is the allergic reaction. Rashes caused by an allergen are usually localized, however. Hives can also cause confusion because they can look nearly identical to rashes and are often considered a type of skin rash. In addition, rashes on a baby’s diaper area are most often irritation caused by dampness. To be safe, have a health professional diagnose the rash to determine if it is something serious like a fungal infection.

A skin rash from an allergic reaction is often localized to the spot the allergen made contact. For example, if an oil you are allergic to touched your hand, that spot may develop the rash. The rash might be itchy and burn or sting when scratched. Many other things can cause similar reactions, so it is important to rule out poison ivy, infection, and other possibilities before determining that the rash is from an allergy.

Sometimes hives, one of the most common allergic reactions, are confused for rashes. Hives are red welts that itch and sometimes spread all over the body. They can look very similar to rashes, to the point that even some medical professionals confuse them. One difference between hives and skin rashes is that hives do not develop blisters or ooze puss, though only some skin rashes progress this far.

Another common type of rash is called a diaper rash, and its location is a tell-tale sign of it not being a skin rash from an allergic reaction. It can affect both babies and adults who wear diapers on a regular basis. The rash usually appears on the buttocks, genital area or thighs, and can be treated with creams or powders. Keeping the area dry by changing wet diapers more quickly can also help.

In general, rashes that quickly fade and disappear completely are nothing to worry about. Those that cover a large portion of the body or that last for days or weeks should be examined by a healthcare professional. Sometimes, redness and scaliness can be an indicator of a fungal infection. Such infections usually do not go away without the help of over-the-counter or prescription anti-fungal creams, depending on their severity.