Hives, or urticaria, are an allergic skin reaction characterized by swollen, red spots that itch. They can be caused by mosquito bites, a fabric allergy or changes in temperature.
Typically, hives symptoms last for up to 24 hours and disappear without leaving any marks or scarring. With chronic urticaria, however, the spots can disappear, then return on other parts of the body and remain for about 6 weeks.
Hives can be controlled by avoiding the irritants that cause them, and with the use of medication (e.g. allergy medication) in some cases.
Symptoms
Hives are spots that are swollen, raised, and red, and are typically accompanied by itchiness. In more severe cases, hives are also associated with difficulty breathing and with swollen lips, eyes or throat. These more severe symptoms require immediate medical attention. Hives can be localized to one skin region or they can be scattered throughout the body, depending on the cause.
Main causes
Causes of hives can vary, but the most common causes include:
- Insect bites
- Allergies to fabric, pollen, latex or sweat
- Colour additives in food, or preservatives
- Excess stress
- Heat or extreme cold
- Certain foods, like peanuts, eggs or seafood
- Infections like mononucleosis
- Medication
- Cleaning products, toxic products or poisonous plants
- Certain illnesses, like lupus or leukemia
It is not always possible to determine the cause of hives, but your doctor or allergist can order bloodwork or complete allergy testing to better understand your symptoms and determine a treatment plan.
Types of hives
Hives can be characterized as acute or chronic, depending on the length of the initial allergy. They are often labeled based on their cause:
- Stress Hives: These hives are triggered by emotions like stress or anxiety, and therefore become worse during periods of high tension.
- Cholinergic Urticaria: Also known as a heat rash, these hives emerge with increases in body temperature from hot tubs, from eating spicy or hot food or from physical activity. It usually lasts for about 90 minutes.
- Urticaria Pigmentosa: These hives are triggered by excess mast cells from the immune system appearing in the skin. These are most commonly seen in babies and children.
- Contact Urticaria: Direct contact with allergens like latex or resin can trigger these types of hives.
- Solar Urticaria: Often referred to as a sun allergy, these hives emerge after sun exposure, and therefore direct exposure to sun rays should be avoided.
Additionally, there is also urticarial vasculitis, which is the most rare type of hives. These hives cause inflammation in the veins, causing pain and burning in affected regions.
How to get rid of hives
Washing affected skin with a mild soap and water is the starting point for treatment, as this will remove any irritants triggering the hives. In cases where the cause of the hives is not clear, or if the symptoms are very intense, your doctor may prescribe allergy medication like loratadine, cetirizine or hydroxyzine. You can also apply a cold compress or anti-itching cream to help alleviate the symptoms associated with hives.
