Physical urticaria is a skin condition in which hives (urticaria) develop from direct contact with certain physical elements.

Unlike contact or allergy-related hives, the stimuli that trigger physical urticaria are nonallergic. Examples include hot or cold objects, sunlight, and pressure.

Physical urticaria is considered a chronic form of urticaria, which means that related hives may occur spontaneously (with or without swelling) for 6 weeks or longer.

This article examines the symptoms of physical urticaria, along with possible causes, diagnosis, and treatment options.

Physical urticaria causes symptoms exclusively in areas of skin that come into contact with the triggering physical stimuli.

Many of the symptoms of physical urticaria are similar to those seen in other types of urticaria. These include hives that are:

  • white or red in color, depending on your natural skin tone
  • itchy
  • irritated and swollen
  • round, ring-shaped, or large patches
  • either localized or widespread
  • variable in size

Additionally, the signs and symptoms of hives can last for just a few minutes or sometimes for up to several hours at a time.

Other symptoms of physical urticaria can vary depending on the underlying cause and can include fatigue, pain, and temporary changes in body temperature.

Most cases of chronic urticaria are idiopathic, which means the exact causes are unknown. Physical urticaria may have an autoimmune factor in its development.

In addition, physical urticaria has several possible triggers and subtypes to consider:

  • Cold: As the name suggests, this type of physical urticaria occurs from direct exposure to a cold item or air temperatures. It’s relatively common, affecting 15% of people, and is more prevalent in females.
  • Heat: This subtype causes hives when your skin is exposed to hot items or air. Unlike cold urticaria, though, heat urticaria is considered rare.
  • Pressure: This type of urticaria develops in areas of the body that are exposed to constant pressure, such as the soles of your feet. It’s most common in males, but is considered rare overall.
  • Light (solar): Also known as “sun allergies,” this subtype can cause hives shortly after exposure to sunlight, especially on your face and hands. It’s relatively common and mostly affects females under the age of 30.
  • Water: Also called aquagenic urticaria, this rare type of physical urticaria is triggered by exposure to water. Hives may develop from exposure to extremely hot or cold water, as well as chlorinated, salt, or even fresh water.
  • Urticaria factitia: Translated as “made urticaria,” these hives are self-induced and develop from scratching, scrubbing, or rubbing your skin. This subtype is most common in young adults and is also known as dermatographic urticaria.
  • Vibration: In some cases, prolonged or long-term use of large equipment such as jackhammers can cause hives.

Doctors typically use a physical exam, personal health history, and lab testing to diagnose physical urticaria.

A doctor may ask you how long you’ve experienced hives, as well as what seems to trigger them. Hives that occur spontaneously for more than 6 weeks usually indicate physical urticaria, while cases that occur for less than 6 weeks may indicate other types of urticaria.

Your doctor may order certain tests to help rule out other possible causes of urticaria, such as allergies. Tests may include blood tests and skin prick tests.

Treatment of physical urticaria usually involves a combination of avoiding triggers and taking medication to alleviate moderate to severe symptoms. Your exact treatment plan will depend on the cause of physical urticaria.

Medications can include topical or oral analgesic medications for pain relief or antihistamines to relieve itchiness. Antihistamines are estimated to be helpful in about 50% of people with chronic urticaria without a cause.

Oral corticosteroids may provide short-term relief for symptoms that do not respond to antihistamines. For more chronic symptoms, a doctor may recommend monthly omalizumab (Xolair) injections.

It’s also important to avoid triggers of physical urticaria, such as wearing tight clothing, scratching your skin, and direct sun exposure. A doctor might also recommend that you:

  • dress appropriately for the weather
  • wear shoe inserts
  • wear sunscreen every day

Also, while physical urticaria is treatable and managed by trigger avoidance, it’s important to know that this condition can recur several months (or even years) later.

Other types of urticaria may be attributed to the following triggers:

  • Environmental allergies: these include allergic reactions to items in your environment, such as pollen, pet dander, and mold
  • Drug allergies: some of the most common medication triggers include aspirin, prescription opiates, and nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Food allergies: if you have food allergies, you might develop hives as a reaction when exposed to the food in question
  • Insect bites: also known as papular urticaria, these types of hives develop when you experience an allergic reaction to bites or stings from insects
  • Viral infections: these are considered the most common trigger of acute urticaria, with hives developing during a viral infection

Physical urticaria is a form of chronic hives that can recur over the course of at least 6 weeks or longer.

Unlike acute cases of hives, physical urticaria is not caused by allergies, viral infections, or any internal causes. Instead, it’s caused by exposure to various forms of physical stimuli.

Identifying physical urticaria can be complicated because the symptoms often resemble those of other types of urticaria.

Consider seeing a doctor to help you determine possible triggers of this condition, as well as for possible treatments if symptoms are severe and affect your quality of life.