The treatment of the physical hives is specific to the type that is diagnosed. In the majority of cases of chronic hives, the causative factor can not be determined. For these people, antihistamines are the mainstay of treatment.
As with acute hives, antihistamines must be taken regularly to prevent the release of histamine. The older antihistamines, such as Benadryl, can cause sleepiness when starting therapy. After about 2 weeks, the sleepiness generally improves or resolves. However, the therapeutic effect of antihistamines does not diminish with regular use. In other words, a person does not develop a tolerance for antihistamines requiring higher doses to stop histamine release. The newer antihistamines, such as Zyrtec, Claritin, and Allegra, do not cause as much sleepiness and are also effective in treating hives.
Sometimes medications such as cimetidine or ranitidine, usually used to reduce stomach acid secretion, are used with antihistamines. These medications are also antihistamines, but they block a different histamine receptor.
A medication called doxepin is a tricyclic antidepressant, or TCA. It also powerfully blocks histamine release and may be used in conjunction with other medications. Its main side effect is also sleepiness.
Oral steroids like prednisone and medrol are considered for cases of hives that don't respond to antihistamines.
Epinephrine is used for severe cases of hives. Epinephrine is a powerful blocker of histamine release and has a rapid onset of effect, but also lasts only a short amount of time in the body.