Dapsone is a sulfone antimicrobial agent and is thought to suppress prostaglandin and leukotriene activity. It is helpful in therapy-refractory cases and is contraindicated in people with G6PD deficiency. Sulfasalazine, a 5-ASA derivative,  is thought to alter adenosine release and inhibit IgE mediated mast cell degranulation, Sulfasalazine is a good option for people with anemia who cannot take dapsone. Hydroxychloroquine is an antimalarial agent that suppresses T lymphocytes. It has a low cost however it takes longer than dapsone or sulfasalazine to work. Omalizumab was approved by the FDA in 2014 for people with hives 12 years old and above with chronic hives. It is a monoclonal antibody directed against IgE. Significant improvement in pruritus and quality of life was observed in a phase III, multicenter, randomized control trial.Immunosuppressants used for CU include cyclosporine, tacrolimus, sirolimus, and mycophenolate. Calcineurin inhibitors, such as cyclosporine and tacrolimus, inhibit cell responsiveness to mast cell products and inhibit T cell activity. They are preferred by some experts to treat severe symptoms. Sirolimus and mycophenolate have less evidence for their use in the treatment of chronic hives but reports have shown them to be efficacious. Immunosuppressants are generally reserved as the last line of therapy for severe cases due to their potential for serious adverse effects. Research
Afamelanotide is being studied as a hives treatment.Opioid antagonists such as naltrexone have tentative evidence to support their use. History
The term urticaria was first used by the Scottish physician William Cullen in 1769.
Chronic urticaria (ordinary urticaria) is defined as the presence of evanescent wheals which persist for greater than six weeks. Some of the more severe chronic cases have lasted more than 20 years. A survey indicated chronic urticaria lasted a year or more in more than 50% of those affected and 20 years or more in 20% of them.Acute and chronic hives are visually indistinguishable. Related conditions
Angioedema
Angioedema is similar to hives, but in angioedema, the swelling occurs in a lower layer of the dermis than in hives, as well as in the subcutis. This swelling can occur around the mouth, eyes, in the throat, in the abdomen, or in other locations. Hives and angioedema sometimes occur together in response to an allergen, and is a concern in severe cases, as angioedema of the throat can be fatal. Vibratory angioedema
This very rare form of angioedema develops in response to contact with vibration. In vibratory angioedema, symptoms develop within two to five minutes after contact with a vibrating object and abate after about an hour. People with this disorder do not experience dermographism or pressure urticaria. Vibratory angioedema is diagnosed by holding a vibrating device such as a laboratory vortex machine against the forearm for four minutes. Speedy swelling of the whole forearm extending into the upper arm is also noted later. The principal treatment is avoidance of vibratory stimulants. Antihistamines have also been proven helpful. Management
The mainstay of therapy for both acute and chronic hives is education, avoiding triggers and using antihistamines.