Pressure urticaria is a type of chronic urticaria that causes recurring hives from pressure applied to your skin. It may be treated with a combination of trigger avoidance and medications.

Better known as “hives,” urticaria is the clinical term for a rash with welts that is typically itchy. Most cases of urticaria are acute with a sudden onset. Examples include rashes caused by allergies or viral infections.

Less commonly, urticaria may be chronic. Pressure urticaria is an example of chronic urticaria, also called chronic inducible urticaria or CIndU for short. The condition is triggered by pressure on your skin, such as straps from a backpack or prolonged periods of sitting or standing.

Like other types of CIndU, pressure urticaria causes symptoms of hives and swelling that can last longer than 6 weeks.

This article takes a closer look at the symptoms, causes, diagnosis, and treatment of pressure urticaria.

Pressure urticaria causes itchy hives that can last more than 6 weeks at a time. The hives initially develop when your skin comes into contact with an external pressure. Symptoms usually develop within 5 minutes of the initial pressure or trigger.

The hives are typically the same color as your natural skin tone, sometimes slightly pinker or redder. They are usually round, but may morph into other shapes, such as rings, large patches, or even map-like outlines.

Hives from pressure urticaria may be accompanied by angioedema, which is severe swelling within the deep tissues of the skin.

Angioedema often affects the mucous membranes and deep tissues of the skin. The main concern is that too much swelling in the airway can make it difficult or impossible to breathe.

While hives can develop anywhere on your body, angioedema is most likely to develop on your:

  • face
  • hands
  • feet
  • genitalia

Pressure urticaria symptoms may last between 8 and 72 hours at a time.

Delayed and immediate pressure urticaria

There are also two subtypes of this condition: delayed and immediate pressure urticaria.

  • Delayed pressure urticaria is considered more common than immediate pressure forms of urticaria. This subtype causes hives about 4 to 6 hours after the initial skin contact.
  • As the name suggests, immediate pressure urticaria causes hives almost immediately upon contact.

When to seek medical help

Consider seeking medical help if you’re experiencing intense, itchy hives for several hours at a time that come and go.

Chronic forms of urticaria, such as pressure urticaria, can significantly interfere with your quality of life. A doctor can help you determine the underlying causes and offer treatments and activity modifications to improve your symptoms.

Sudden, intense swelling of the skin should also be evaluated by a medical professional right away.

Common triggers for pressure urticaria include:

  • prolonged standing or walking
  • jobs that involve physical labor
  • sitting on an object (such as in a car seat or on a horse) for long periods of time
  • carrying a heavy bag by hand or on your shoulders
  • standing on a material that digs into your feet, such as a ladder rung
  • pressure against your skin from a seatbelt
  • wearing tight clothing that rubs against your skin
  • any object that is pressed against your skin for long periods of time

Potential risk factors

In some cases, the symptoms of pressure urticaria may be exacerbated by menstruation, heat, or taking aspirin.

It’s also possible that chronic urticaria could have an autoimmune component. In such cases, your body may produce autoantibodies that attack normally healthy immune cells.

The autoimmune connection is thought to be more common in chronic spontaneous (idiopathic) urticaria than in CIndU types, where the triggers are known. Pressure urticaria falls into the latter group.

Nevertheless, some experts believe that mast cells and histamine release contribute to hives in pressure urticaria, and that the condition might also be more prevalent with autoimmune conditions.

As such, an existing autoimmune condition may also increase your risk for this type of chronic urticaria. Examples include:

Of these, autoimmune hypothyroidism is the most common, observed in up to 9.8% of people with pressure urticaria.

How prevalent is pressure urticaria?

Overall, chronic urticaria is thought to affect about 23 out of every 10,000 people in the United States. It tends to be more common in females.

The exact prevalence of pressure urticaria isn’t known. It’s thought to be less common than acute forms, but more common than chronic spontaneous urticaria. Pressure urticaria has a peak onset during your 20s and 30s.

If you suspect you might have symptoms of pressure urticaria, consider making an appointment with a doctor for a diagnosis. They will first evaluate your medical history and the signs and symptoms you’re experiencing.

Since the signs and symptoms of pressure urticaria are often similar to other forms of chronic inducible urticaria, the diagnosis of this condition can involve a process of elimination.

A doctor may also order antibody tests to determine whether there is a possible autoimmune component to consider. In this case, treatment may also address the underlying autoimmune condition.

As with other types of chronic urticaria, pressure urticaria may disrupt your overall quality of life when symptoms develop after trigger exposure.

Treatment of intense itching and swelling is possible, although challenging. To date, antihistamines are the only effective treatments recommended for pressure urticaria. These work by reducing histamine release from mast cells.

Oral corticosteroids can also be used to induce immediate symptom relief for people with severe itching.

For acute flares of chronic pressure urticaria, short courses of systemic corticosteroids may help alleviate symptom severity and reduce the duration of the flare. Topical corticosteroids do not have a role in its treatment.

It’s important to ask a doctor before taking antihistamines for pressure urticaria relief. They can advise you on the best brand and dosage, and perhaps even recommend a prescription-strength version.

While antihistamines are considered first-line treatments for pressure urticaria symptoms, researchers are investigating possible future alternatives. These include monoclonal antibodies, such as omalizumab (Xolair).

Treatment may help alleviate symptoms of CIndU, but it cannot prevent them. As such, the best way to prevent symptoms of pressure urticaria is to avoid the activities that trigger the condition as much as possible.

For example, you can:

  • wear a cross-body bag or a backpack instead of a bag over one shoulder
  • avoid pressing your hands or feet against objects for long periods of time
  • wear loose, breathable clothing that doesn’t rub against your skin
  • take breaks to stretch your legs during bike rides or horseback riding
  • limit the amount of exposure you have with any heavy items pressing into your skin

Any unusual hives and swelling that are chronic should be evaluated by a doctor. If you notice that symptoms develop after pressure stimuli, consider seeing a medical professional right away.

Although the exact causes of pressure urticaria are unknown, treatments can help reduce symptoms and improve your overall quality of life.

Avoiding any known physical triggers can also reduce the risk of future episodes.