The skin acts in conjunction with other systems in our body to remove toxins and waste. Hives can be a natural reaction to the presence of a foreign substance in the body. However, an offending substance need not enter the body to trigger an outbreak of hives. Merely coming into contact with various substances, such as pesticides, soaps, shampoos, hair sprays, residues from laundry products or dry cleaning chemicals on clothing, or any other of a vast array of other seemingly innocuous household items can unleash a maddening attack of hives. The severity of a hives outbreak can vary from case to case as well as from person to person.
Viruses also can cause hives.
Hepatitis B and Epstein-Barr virus, the virus that causes infectious mononucleosis, are the two most common culprits. Some bacterial infections likewise can cause outbreaks of hives, both chronic and acute. An association between Candida albicans and chronic hives has been established in several clinical studies over the past twenty years. Antibiotics such as penicillin and related compounds are the most common cause of drug-induced hives. At least 10 percent of the American population is thought to be allergic to penicillin.