Allergies, exercise, and detergents are common causes of hives in adults. In addition, hives are idiopathic, meaning that the cause of some cases is unknown. Food and medication allergies are very common and likely the culprit if the adult recently tried a new medication or food. Hives due to exercise is less common than food- or medication-induced hives, but still occurs in many adults. Hives may also caused by clothing that is too tight, too loose, or washed in a detergent that irritates the person’s skin.
Food allergies are an especially common cause of hives in adults. If a person develops hives and remembers trying a new food recently, he or she is likely experiencing an allergic reaction. Shellfish, nuts, and gluten are some things people are frequently found to be allergic to. To prevent another potentially worse breakout of hives, the food should be avoided in the future.
In addition to food allergies, some drugs might cause an allergic hive reaction in adults. Hives are listed as a possible side effect in many over-the-counter and prescription medications. These reactions can range from mild to severe, but normally diminish within 24 hours. If they are painful and last longer than 24 hours, it is generally recommended to see a doctor.
Even an activity that is often considered harmless, like exercise, can cause hives in adults. Due to a condition called exercise-induced urticaria, some adults get hives, in addition to other negative symptoms, as a result of exercising. This is a dangerous condition and, if it is suspected, it is recommended the person see a doctor. Exercise does not have to be the direct trigger, however. For example, some adults are afflicted with hives as an allergic response to sweat, which can be caused by exercise.
At times, even clothing can result in hives in adults. Clothing can chafe or cause skin irritation by being too tight or too loose. Another reason clothing can cause irritation resulting in hives is due to an allergic reaction to the detergent that was used to wash the clothing. If this is the case, the situation can often be fixed by soaking the offending clothing in an ammonia-based solution and switching to a type of detergent thought to be less likely to irritate the skin. It can often be difficult to discover exactly what is causing hives in adults, but these are a few potential issues that can be ruled out without medical treatment.