Hives occur across all age groups and can occur on any part of the body. Characterized by red raised bumps or plaques with a pale center, lesions range in size from a few millimeters to several centimeters, may be round, oval in shape, and can grow together or spread. Individual lesions can evolve over minutes to hours and usually disappear in less than 24 hours without leaving any residual discoloration or bruising. These lesions are intensely itchy and can be disruptive to quality of life, work, school, and sleep.
Hives are classified according to defined timelines. Acute urticaria refers to hives that last for less than six weeks in duration. Potential triggers for acute urticaria include bacterial and viral infections, IgE mediated reactions such as allergic reactions to foods or insect stings, contact allergens and direct cell activation by certain medications or supplements. Acute urticaria will resolve once the identified trigger is removed and within 6 weeks. Chronic urticaria is hives that last for greater than six weeks and occur most days of the week.
Hives are mediated by mast cells. Mast cells release multiple mediators upon activation including histamine, which incites itching. When mast cells are activated on the top layer of the skin, the dermis, hives present. When mast cells release mediators in the deeper layers of the skin, the epidermis, swelling or angioedema forms. Angioedema occurs in approximately 40% of individuals who have chronic urticaria.
Myth: Hives are not present; need to be present for medical evaluation.
Fact: It is not necessary to have physical evidence of hives on the date of your medical visit. However, photos taken of your hives are very helpful. A good history of your hives is important in shaping treatment.
Myth: Chronic spontaneous urticaria is due to an allergic reaction.
Fact: No, this is usually not the cause. The likelihood of identifying a cause of chronic urticaria is very low. Blood work can be performed to help rule out an underlying disorder, usually autoimmune in nature, however in about 90% of chronic cases, the cause is “idiopathic,” meaning doctors can’t find a specific external trigger. Since there is no “trigger” to avoid, treatment focuses on long-term management.
Myth: Allergic skin testing will help to identify the cause of hives.
Fact: Acute urticaria causes may sometimes be identified with a thorough history. However, allergic skin testing is not helpful in chronic spontaneous urticaria and many cases of acute urticaria. Extensive allergic skin testing to determine the cause of urticaria is not recommended as it is neither cost-effective and provides little diagnostic value. If there is a direct cause and effect with food, you will note it within a few minutes to several hours after ingestion. For example, if you are shrimp allergic, ingestion will trigger a reaction within that time frame.
Myth: Chronic spontaneous urticaria can be cured.
Fact: Chronic spontaneous urticaria is a chronic autoimmune condition that can go into remission in six to 12 months, but in many patients the duration may last as long as five years before remission; however, reactivation can occur. Treatment currently is available and has been successful in achieving control. Avoidance of nonspecific triggers can also help decrease chronic spontaneous urticaria.
Some patients will find that taking a nonsteroidal anti-inflammatory drug (such as ibuprofen) or aspirin will trigger hives. Alcohol may also worsen urticaria but the evidence is low. There are some additional triggers for inducible, previously known as physical, urticarias, such as light, heat, pressure, vibration and stroking of the skin. Inducible urticarias frequently occur with both acute and chronic spontaneous urticaria.
Myth: There are no good treatments for hives.
Fact: Acute urticaria responds very well to non-sedating antihistamines and removal or treatment of the cause when evident. Fifty percent of chronic spontaneous urticaria patients will respond to up to four times the standard dose of nonsedating antihistamines. The remainder will show additional benefit by adding an injectable medication called a monoclonal antibody, such as Xolair (omalizumab) or Dupixent (dupilumab). Most recently, a new first-of-its-kind drug called Rhapsido (remibrutinab), has been approved as an add-on treatment for chronic spontaneous urticaria. Rhapsido is a Bruton Kinase inhibitors oral pill taken twice daily. Other therapies, such as immunosuppressant medications, may be beneficial as well. It is important that you consult with your allergist / immunologist for chronic urticaria evaluation to find the treatment that works best for you.
