Overview By Mayo Clinic Staff Print Hives on light skinHives on light skinHives, also known as urticaria, are reddened, itchy welts that may be triggered by substances or situations, such as heat, exercise and stress. Hives on dark skinHives on dark skinChronic hives appear daily or almost daily for six weeks or more. Hives — also known as urticaria (ur-tih-KAR-e-uh) — is a skin reaction that causes itchy welts, which can range in size from small spots to large blotches several inches in diameter. Hives can be triggered by exposure to certain foods, medications or other substances. Angioedema is a related type of swelling that affects deeper layers in your skin, often around your face and lips. In most cases, hives and angioedema are harmless and don't leave any lasting marks, even without treatment. The most common treatment for hives and angioedema is antihistamine medication. Serious angioedema can be life-threatening if swelling causes your throat or tongue to block your airway. Request an Appointment at Mayo Clinic Symptoms & causes Nov. 09, 2016 Print Share on: Facebook Twitter References Habif TP. Urticaria, angioedema, and pruritus. In: Clinical Dermatology. 6th ed. Philadelphia, Pa.: Elsevier; 2016. www.clinicalkey.com. Accessed Sept. 10, 2016. Hives (urticaria). American College of Allergy, Asthma, and Immunology. http://acaai.org/allergies/types/skin-allergies/hives-urticaria. Accessed Sept. 10, 2016. Ferri FF. Urticaria. In: Ferri's Clinical Advisor 2017. Philadelphia, Pa.: Elsevier; 2017. https://www.clinicalkey.com. Accessed Sept. 10, 2016. Bingham CO. New onset urticaria. http://www.uptodate.com/home. Accessed Sept. 10, 2016. Zuraw B, et al. An overview of angioedema: Clinical features, diagnosis, and management. http://www.uptodate.com/home. Accessed Sept. 10, 2016. RelatedSymptom CheckerMilk allergyDrug allergyMosquito bitesAlcohol intolerancePeanut allergyEgg allergyWheat allergyShellfish allergySun allergyPenicillin allergyBedbugsEdemaAbdominal pain Hives and angioedemaOverviewSymptoms & causesDiagnosis & treatmentDiagnosisTreatmentClinical trialsPreparing for your appointmentSelf-managementMore aboutIn-DepthMultimediaResources Advertisement Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. Advertising & Sponsorship Policy Opportunities Ad Choices Mayo Clinic Store Check out these best-sellers and special offers on books and newsletters from Mayo Clinic. The Mayo Clinic Diet BookMedical News From a Trusted SourceMayo Clinic on Healthy AgingA New Perspective on Alzheimer'sThe Mayo Clinic Diet Online Diagnosis & treatmentRequest an AppointmentDiagnosisTreatmentClinical trialsPreparing for your appointment CON-20212564 Patient Care & Health Information Diseases & Conditions Hives and angioedema