Facts and Myths About Urticaria (Hives)

Urticaria (hives) affects approximately 20% of the population at some point in their lives. Hives occur across all age groups and is classified according to defined timelines. Acute urticaria refers to hives that last for less than six weeks in duration. Chronic urticaria is hives that last for greater than six weeks and occur most days of the week. Urticaria, both acute and chronic, can occur anywhere on the body. However, areas prone to compression by clothing, especially on the waist or underarm are more frequently severely affected.

Hives, whether acute or chronic, can occur on any part of the body. Individual lesions can evolve over minutes to hours and usually disappear in less than 24 hours without leaving any residual hyperpigmentation or bruising. The lesions are intensely pruritic and may include swelling of the deeper tissue resulting in angioedema. This occurs in approximately 40% of individuals who have chronic urticaria. If angioedema occurs without hives, consideration should be given to an underlying abnormality of the bradykinin system or a drug reaction, such as angioedema occurring with ACE inhibitors or medications used to help lower blood pressure.

Urticarial lesions are red raised bumps or plaques with a pale center. The lesions range in size from a few millimeters to several centimeters in size. They may be round, oval in shape and can grow together or spread. The itching associated with urticaria can be disruptive to quality of life, work, school and sleep.

Hives are mediated by cutaneous mast cells in the dermis or middle layer of skin. Mast cells release multiple mediators upon activation including histamine, which incites itching.

Acute urticaria has numerous potential triggers, including bacterial and viral infections, IgE mediated reactions, contact allergens and direct cell activation by drugs.

Viral infections tend to be the predominant cause of acute urticaria in children. Mycoplasma pneumonia infection is a common cause in children and adults. Mast cell activation with mediator release occurs after bee, wasp, hornet and fire ant sting with resultant hives. Bed bugs, fleas and mite bites trigger papular urticaria. An IgE mediated reaction can result in hives after food ingestion. The most common foods involved in food allergy are milk, eggs, peanut, tree nuts, soy, cow’s milk, wheat, fish, shellfish and sesame seeds. Food additives are rarely a cause, however, annatto yellow dye and carmine (i.e., red dye) are known causes. Contact allergens can occur on exposed areas of skin often exposed to raw fruit, vegetables and animal saliva. 

Certain drugs are nonspecific mast cell activators and will cause hives. Opioids, muscle relaxants, vancomycin and radiographic contrast media are classic examples. In addition, urticaria may occur as an early symptom to an autoimmune disease, such as rheumatoid arthritis and lupus. Urticaria may also appear with Lyme disease and hepatitis.

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 stress, a pet or foods.
Fact: No, these are usually not the causes. The likelihood of identifying a cause is very low. This used to be called chronic idiopathic urticaria.

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 and spices 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 nonsedating 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 with adding omalizumab, a monoclonal antibody that binds to the high affinity IgE receptor on mast cells, or dupilumab, another monoclonal antibody. Approximately 60% of patients will achieve remission with the remainder needing cyclosporin. Newer treatment approaches are currently awaiting approval, including Bruton Kinase inhibitors and c-kit inhibitors. Other therapies can be considered. We recommend that you see your allergist / immunologist for chronic urticaria evaluation and treatment.  

Myth: Extensive blood work is necessary to evaluate patients with chronic spontaneous urticaria. 
Fact: Blood work usually does not need to be performed to support the diagnosis that is determined by an accurate history and physical examination. Limited laboratory testing including a CBC (complete blood count), CRP (C-reactive protein) and TSH (thyroid stimulating hormone) may be considered, depending on the case, by the allergist / immunologist. Extensive laboratory testing is usually of very limited value. In patients not responsive to H1-antihistamines other tests may be considered to determine chronic autoimmune urticaria.

Myth: Itchy skin rashes are usually due to urticaria.
Fact: Diseases are frequently misdiagnosed as chronic spontaneous urticaria. It is not unusual due to the pruritic nature of the condition. Some may be misdiagnosed as urticaria but have other conditions, such as bullous pemphigoid, nummular dermatitis, dermatomyositis and Lyme disease. However, the urticaria like lesions in these patients are not evanescent.

Your allergist / immunologist is specifically trained in the evaluation and treatment of hives. Please consult them for further information on hives.  

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7/8/2025