Allergies are an abnormal immune response to a normally innocuous substance. Hives are a type of skin allergy characterized by itchy skin swelling. Hives may occur alone or in association with a more severe allergic response, known as anaphylaxis. Anaphylaxis affects nearly every system in the body and can be life-threatening. People at risk for these reactions should be prepared by having a shot of epinephrine with them at all times.
Cause of Hives
Hives are an allergic reaction triggered by a variety of foreign substances. Common culprits include medications, ingested foods, insect bites, viruses and parasite infestations. In many cases, the cause of hives may not be known. Hives are an allergic reaction that occurs throughout the body. The immune system reacts to the foreign particle and activates cells known as mast cells. These cells release a large amount of histamine, which causes blood vessels to become swollen and leaky.
Signs, Symptoms and Treatment
Hives usually take the form of itchy, red welts over the skin. They may slowly enlarge and combine to form large areas of raised skin. Putting pressure over the hives can cause them to go white. Patients can treat their condition by avoiding the trigger, if known, and by taking medications. The most commonly used medications for an isolated case of hives are antihistamines. Nonsedating antihistamines such as cetirizine or loratidine can be tried; however, if symptoms persist, then the more powerful, sedating drugs such as diphenhydramine can be used. Speak with your doctor about a treatment suitable for you.
Severe Allergic Response
The severe allergic response is termed as anaphylaxis, which is a life-threatening condition. Nearly every organ is involved in this reaction. One of the earlier signs of anaphylaxis is itchy hives throughout the body. More importantly, however, the condition can cause constriction of the airways, leading to breathlessness and wheezing. Because of the dilation of blood vessels throughout the body, there may be a dangerous drop in blood pressure. The heart rate increases and may lose its normal rhythm. Individuals may also have stomach pain and cramping.
Treatment of Severe Allergy
People with severe allergies need to be taken immediately to the emergency room. The most critical treatment for these conditions is epinephrine, given as an injection. This can raise the blood pressure and open the airways. Patients who know they are susceptible to extreme allergies should always carry an epinephrine pen, prescribed by a doctor, in case of an emergency. In the emergency room, a breathing tube may be needed to keep the airway open.
References
- "Kumar and Clark's Clinical Medicine"; Praveen Kumar, et al.; 2009
- MayoClinic.com: Anaphylaxis
- PubMed Health: Hives
- PubMed Health: Anaphylaxis
