Medication Summary
Medications used to treat chronic urticaria include antihistamines (first- and second-generation), anti-inflammatory agents, and sulfones.
Antihistamines, Second Generation
Class Summary
Second-generation antihistamines, also known as less-sedating or low-sedation antihistamines, produce less sedation than traditional H1 blockers because they are less lipid-soluble and only cross the blood-brain barrier in small amounts. They also have longer half-lives, allowing less frequent dosing.
Cetirizine (Zyrtec)
Cetirizine forms a complex with histamine for H1-receptor sites in blood vessels, the gastrointestinal (GI) tract, and the respiratory tract. It is available as a 5- or 10-mg tablet and as a syrup containing 1 mg/mL (5 mg/5 mL [tsp]).
Fexofenadine (Allegra)
Fexofenadine competes with histamine for H1 receptors in the GI tract, blood vessels, and the respiratory tract, reducing hypersensitivity reactions. It does not sedate. Fexofenadine is available as a 30-, 60-, or 180-mg tablet. The Allegra ODT tablet is formulated for disintegration in the mouth immediately after administration. Each orally disintegrating tablet contains 30 mg of fexofenadine hydrochloride. The Allegra oral suspension contains 6 mg/mL of fexofenadine hydrochloride (30 mg/5 mL).
Loratadine (Claritin, Alavert)
Loratadine selectively inhibits peripheral histamine H1 receptors. It is available in 10-mg tablets or 10-mg RediTabs; the syrup is 5 mg/5 mL (tsp).
Desloratadine (Clarinex)
Desloratadine is a long-acting tricyclic histamine antagonist that is selective for H1 receptors. It relieves nasal congestion and alleviates the systemic effects of seasonal allergy. Desloratadine is a major metabolite of loratadine, which, after ingestion, is extensively metabolized to the active metabolite 3-hydroxydesloratadine. The tablet is 5 mg; the syrup is 0.5 mg/mL (2.5 mg/5 mL [tsp]); and the RediTabs (orally disintegrating desloratadine tablets) are 2.5 mg and 5 mg.
Levocetirizine (Xyzal)
Levocetirizine is an H1-receptor antagonist, an active enantiomer of cetirizine. It is a second-generation prescription antihistamine.
Antihistamines, First Generation
Class Summary
First-generation antihistamines compete with histamine at the tissue-receptor level, preventing it from carrying out its mediator functions in urticaria.
Diphenhydramine (Benadryl, Diphenhist, Allerdryl)
Diphenhydramine is given for symptomatic relief of symptoms caused by release of histamine in allergic reactions.
Hydroxyzine (Vistaril)
Hydroxyzine antagonizes H1 receptors in the periphery. It may suppress histamine activity in subcortical region of the central nervous system (CNS). Hydroxyzine is available in 10-, 25-, and 50-mg tablets or capsules and in a 100-mg capsule. The suspension is 25 mg/5 mL, and the syrup is 10 mg/5 mL (tsp).
Leukotriene Receptor Antagonists
Class Summary
Leukotriene antagonists have been shown to be superior to placebo in the treatment of patients with chronic urticaria but are considered less effective than nonsedating antihistamines; however, the 2 classes of agents can be combined. Montelukast 10 mg/day may be particularly helpful for patients experiencing flare-ups due to aspirin or other NSAIDs. Montelukast is approved for treatment of perennial allergic rhinitis in children aged 6 months and older.
Montelukast (Singulair)
Montelukast is a selective competitive inhibitor of the cysteinyl leukotriene receptor. Montelukast is the last agent introduced in its class. The advantages are that it is chewable, it has a once-a-day dosing, and it has no significant adverse effects.
Anti-Inflammatory Agents
Class Summary
Anti-inflammatory agents modify the immune response to diverse stimuli.
Prednisone
Prednisone is an immunosuppressant used to treat autoimmune disorders; it may decrease inflammation by reversing increased capillary permeability and suppressing polymorphonuclear leukocyte (PMN) activity. It stabilizes lysosomal membranes and suppresses lymphocytes and antibody production.
Colchicine (Colcrys)
Colchicine decreases leukocyte motility and phagocytosis in inflammatory responses.
Immunosuppressants
Class Summary
These agents inhibit immune reactions that result from diverse stimuli. Patients with autoimmune urticaria may benefit from the administration of methotrexate or cyclosporine.
Cyclosporine (Gengraf, Neoral, Sandimmune)
Cyclosporine is a cyclic polypeptide that suppresses some humoral immunity and, to a greater extent, cell-mediated immune reactions, such as delayed hypersensitivity, allograft rejection, experimental allergic encephalomyelitis, and graft versus host disease for a variety of organs. For children and adults, base the dosing on ideal body weight. Cyclosporine 4-6 mg/kg/day has been shown in randomized double-blind studies to be effective for chronic urticaria. Cyclosporine has a better risk-to-benefit ratio than systemic corticosteroids.
Cyclosporine is recommended only for patients with severe disease refractory to high doses of oral antihistamines. Cyclosporine therapy for chronic urticaria should be limited to 3 months or less. A sustained remission is observed in approximately one third of patients treated with this medication.
Methotrexate (Rheumatrex, Trexall)
Methotrexate has an unknown mechanism of action in the treatment of inflammatory reactions; it may affect immune function. Methotrexate ameliorates symptoms of inflammation (eg, pain, swelling, stiffness). It is an antimetabolite that inhibits deoxyribonucleic acid (DNA) synthesis and it may suppress immune system. Adjust the dose gradually to attain a satisfactory response.
Monoclonal Antibody
Class Summary
Monoclonal antibodies directed to immunoglobulin E (IgE) binding may reduce the release of mediators that provoke an allergic response. These agents may be considered when H 1 -receptor antagonists are ineffective.
Omalizumab (Xolair)
Omalizumab is a recombinant humanized monoclonal antibody administered by SC injection every 4 weeks. It selectively binds to IgE and inhibits binding to IgE receptors on the surface of mast cells and basophils. It is indicated for chronic idiopathic urticaria in adults and children aged 12 years or older who remain symptomatic despite anti-H 1 antihistamine treatment.
Antidepressants, TCAs
Class Summary
Agents in this class antagonize the histamine (H1) receptor, preventing histamine from causing urticaria. The tricyclic antidepressant doxepin is used in urticaria for its sedative and antihistaminic properties. Oral doxepin may be considered if oral antihistamines are not helpful.
Doxepin
Doxepin inhibits histamine and acetylcholine activity and has proven useful in the treatment of allergic dermatologic disorders. The oral form is marketed as an antidepressant but is used also for its antihistaminic/antipruritic effects. The dosage is 10-25 mg at night in adults; if necessary, this can be gradually increased to a maximum dose of 75 mg/d for dermatoses.
Antibiotics, Other
Class Summary
Certain antibiotics may modulate the immune system.
Dapsone
The mechanism of action of dapsone is similar to that of sulfonamides, in which competitive antagonists of para-aminobenzoic acid (PABA) prevent formation of folic acid. The effects of this agent on inflammatory reactions are unknown.
Thyroid Hormones
Class Summary
Thyroid hormones may be used to suppress thyroid activity and possibly the immune process.
Levothyroxine (Levothroid, Levoxyl, Synthroid, Unithroid)
In active form, levothyroxine influences the growth and maturation of tissues. It is involved in normal growth, metabolism, and development.
Some patients with chronic urticaria and antithyroid antibodies benefit from levothyroxine treatment, perhaps because of suppression of thyroid activity and, possibly, the autoimmune process. The goal of treatment is to suppress thyrotropin maximally without rendering the patient clinically hyperthyroid. The urticaria may respond within 2 weeks of initiation of adequate treatment. Some patients may maintain a sustained remission after 3-6 months of treatment, at which point the levothyroxine can be tapered and then discontinued.
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Urticaria developed after bites from an imported fire ant.
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Urticaria associated with a drug reaction.
