Symptoms of Urticaria (Hives)

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While the symptoms of urticaria (hives) may seem relatively self-apparent, they are frequently mistaken for those of other skin conditions such as eczema, rosacea, and pityriasis rosea. But, in the same way that the biological mechanism of urticaria is specific, so, too, are the signs and characteristics of the common skin rash—if you consider them carefully.

While hives (also referred to as wheals or weals) can differ in their distribution and appearance, they are characterized by itchy, raised welts on the skin's surface that are either red or skin-colored.

Frequent Symptoms

Urticaria is caused by an inflammatory reaction that prompts capillaries in the dermis (the layer of tissue just beneath the outer skin) to leak fluid. When this happens, the accumulation of fluid results in a defined area of raised skin that persists until the fluid is eventually reabsorbed into the surrounding cells.

Hives have specific characteristics that set them apart from other skin conditions:

  • The elevated area of skin has a clearly defined border.
  • When you press the rash, it will "blanches" (turns white).
  • They will be itchy, sometimes intensely so. There may also be paired with pain or a burning sensation.
  • They can appear on anywhere on the body and change shape, move around, disappear, and reappear over short periods of time.
  • When they resolve, the skin will return to normal without scarring.
  • Most will not be accompanied by systemic reactions such as fever, nausea, muscle aches, joint pain, or headaches.

Urticaria is classified as being either acute or chronic depending on the duration of the eruption. Acute hives last for less than six weeks, while chronic hives extend well beyond six weeks.

Acute urticaria is more common in children and young adults. The majority are classified as idiopathic, meaning that we don't know the cause. Most cases are self-limited; individual lesions tend to resolve on their own within a few hours. An eruption rarely lasts more than several days, although it may recur over weeks. If a cause is found, it is usually related to an infection, insect bite, or a food or drug allergy.

Chronic urticaria, by contrast, often requires medical treatment. In one 2014 study, 75 percent of people with chronic hives had symptoms that lasted for longer than a year, while 11 percent had symptoms for five or more years. In half of the cases, the offending agent was never found.

Urticaria is known to affect up to 20 percent of the population and strikes people irrespective of age, race, or gender. Hives most often appear in the evening or early morning just after waking. Itching is typically worse at night, often interfering with sleep.

By Type

The distribution and appearance of hives can vary significantly. Some may be widespread, while others may be diffuse or limited to a single, small weal. The appearance of a hive can sometimes give a clue as to the underlying cause.

For example:

  • Cold urticaria, caused by exposure to cold temperatures, usually manifests with welts that are between a quarter of an inch and an inch in size that are either slightly reddish or skin-colored. Fainting can occur if large areas of skin are involved.
  • Cholinergic urticaria, also known as heat rash, is caused by excessive sweating and will appear as very small weals surrounded by bright red flares. Strenuous exercise is a common cause.
  • Dermographism urticaria is caused by the firm stroking of the skin and manifests with hives along the line of contact. The weals tend to appear five to 10 minutes after contact and generally disappear 10 to 15 minutes after they occur.
  • Pressure urticaria is caused by any pressure placed on the skin, including tight clothing or standing on your feet too long. It manifests with a denser, localized eruption that is red, itchy, and maybe even a little painful.
  • Solar urticaria, caused by exposure to ultraviolet (UV) light, appears in areas of exposed skin, often within minutes of exposure. The rash is very itchy and appears "angry" with an often intense redness and warmth. As with cold urticaria, fainting can occur if the hives are widespread.
  • Vibratory urticaria can be caused by any form of vibration, including clapping or a bumpy car ride. It tends to be short-lasting, appearing and disappearing within an hour. While difficult to distinguish by looks alone, vibratory hives are sometimes accompanied by unusual symptoms such as flushing, headaches, blurry vision, or a metallic taste in the mouth.
  • Water urticaria (aquagenic urticaria) is a rare form of hives caused by contact with water. The hives tend to be small and most often develop on your neck, upper trunk, and arms. As with vibratory urticaria, it tends to come and go within an hour.

Rare Symptoms

Less commonly, urticaria may precede a severe, all-body allergic reaction known as anaphylaxis. Anaphylaxis is often caused by a hyperallergic response that triggers the development of hives, angioedema (a related skin condition affecting deeper layers of tissue), and severe respiratory symptoms.

Common allergy triggers are food, medications, vaccines, and insect stings, although some cases have no known causes. Symptoms of anaphylaxis include:

  • Widespread hives and angioedema with hot skin 
  • Coughing, sneezing, and wheezing
  • Throat tightness and shortness of breath
  • Swelling of the lips and/or tongue
  • Rapid or irregular heartbeat
  • Dizziness or lightheadedness
  • Stomach cramps
  • Nausea, vomiting, and diarrhea
  • Chest pains
  • Breathing restriction advancing to airway obstruction
  • Confusion
  • A feeling of impending doom
  • Fainting and collapse
  • Seizures

If left untreated, anaphylaxis can lead to shock, asphyxiation, coma, cardiac or respiratory failure, and death.

When to See a Doctor

If a case of hives is uncomplicated with no accompanying symptoms other than itching, you can usually treat it at home. Most will resolve within a few hours to several days. If it persists for more than a week or starts to worsen, see a doctor as soon as possible.

If your symptoms are recurrent and unexplained, ask your doctor for a referral to either a dermatologist, who can run tests to identify possible triggers, or an allergist, who can check whether an allergen (allergic trigger) is to blame. Your doctor may also want to check for undiagnosed infections (such as hepatitis B) or autoimmune diseases (such as Hashimoto's thyroiditis), for which recurrent hives are common.

On the other hand, if your hives are accompanied by symptoms such as breathing difficulty, widespread swelling, heartbeat irregularities, and/or vomiting, call 911 or have someone rush you to the nearest emergency room.

Sources:

Ferrer, M.; Bastra, J.; Gimenez-Arnau, A. et al. Management of urticaria: not too complicated, not to simple. Clin Experimental Allergy. 2014; 45(4):731-43. DOI: 10.1111/cea.12465.

Schaefer, P. Acute and Chronic Urticaria: Evaluation and Treatment. Am Fam Physician. 2017; 95(11):717-724.