Pressure Urticaria

Updated: Aug 08, 2016
  • Author: Sarah Beggs, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Pressure urticaria is a rare entity of physical urticaria, a subset of chronic urticaria, which presents with erythematous swelling at sites of pressure. Chronic urticaria is diagnosed when patients have ongoing urticaria for more than 6 weeks. An inciting event or etiology is usually not identified for patients with chronic urticaria, and the term chronic idiopathic urticaria (CIU) is often used. A proportion of patients diagnosed with chronic urticaria have physical urticaria, [1] which is urticaria caused by a physical stimulus, such as mechanical (friction, vibration, pressure), thermal, or electromagnetic waves. [2]

Pressure urticaria may occur immediately (within minutes) or more commonly 4-6 hours after a pressure stimulus. [3] For this reason, the term delayed pressure urticaria (DPU) is typically used. It appears as an erythematous, cutaneous, and often subcutaneous edema. The reaction may last up to 72 hours and can be associated with pruritus, burning, and pain. [4] Pressure sites, including the hands, feet, trunk, buttocks, and legs, are most commonly affected. Lesions can be induced by a variety of stimuli, including standing, walking, wearing of tight clothes, and sitting or leaning on a hard surface. [5]  See the image below.

Delayed pressure urticaria. Courtesy of DermNet Ne Delayed pressure urticaria. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/reactions/pressure2.jpg).

For further information on urticaria, see Contact Syndrome Urticaria, Dermographism Urticaria, and Solar Urticaria. For patient education resources, see the Allergy Center and the Skin, Hair, and Nails Center, as well as Hives and Angioedema.

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Pathophysiology

The pathogenesis of delayed pressure urticaria (DPU) is relatively unknown. Although the trigger stimulus is typically identified, no allergen has been established. The general pathogenesis of urticaria (hives) can be mediated immunologically or nonimmunologically, usually antibodies against IgE molecules are involved. IgE molecules attach to mast cells. When an antibody or autoantibody attaches to the antigen-binding site of the IgE molecule, a bridge is formed between two or more IgE molecules. This induces mast cell degranulation, releasing multiple proinflammatory mediators, including histamine. In chronic idiopathic urticaria (CIU), the mast cells are inappropriately activated. [6]

In DPU, mast cells and histamine are believed to play a role in the disease pathogenesis, as injections of a mast cell degranulator, compound 48/80, lead to the formation of wheals in patients with DPU both 15 minutes after injection, as well as at 6-8 hours after injection. Injections in patients with chronic urticaria but without DPU produce wheals at 15 minutes that diminish over time. Histamine injections in both patients lead to initial wheal formation with no late phase reaction. [7]

Histamine levels are increased in the lesional skin, while intracellular histamine levels are decreased in peripheral white blood cells. [8] There is also an increased stimulation of histamine release. Despite these findings, histamine is unlikely to be the sole mediator in pressure urticaria. This is further demonstrated in the inconsistent effectiveness of antihistamine treatment in pressure urticaria.

Other mediators are believed to be involved. This includes eosinophils (as suggested by the presence of eosinophilia), eosinophil cationic protein (ECP), and eosinophil cationic factor (ECF) found in biopsy specimens from select patients with DPU, particularly those with bullous DPU. [9] In addition, elevated concentrations of interleukin (IL)–1a, IL-5, and IL-6; tumor necrosis factor (TNF)–alpha; and leukotrienes have also been found in lesional skin of pressure urticaria patients. [10, 11, 12] Vascular endothelial growth factor has also been found to be elevated in patients with DPU. [13] Abnormalities in platelets and fibrin or fibrinolysis have also been investigated. [14, 15] Systemic inflammation has also been suggested with elevations seen in C-reactive protein (CRP) and sCD40L, a platelet activator. [16, 17]

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Etiology

Pressure stimuli may include the following:

  • Standing, walking, leaning, or sitting
  • Using tools 
  • Carrying a handbag or backpack
  • Wearing tight-fitting clothes (eg, bra straps or watches)
  • Sexual intercourse
  • Tampon use

Occasionally, delayed pressure urticaria (DPU) is aggravated by heat, aspirin, or menstruation. Exacerbation of the condition during medical procedures is a reasonable possibility; urticaria flares following endoscopy have been described. [18]

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Epidemiology

Delayed pressure urticaria (DPU) is generally considered a rare entity; however, this may be due to the fact that it is not consistently recognized. One study of 2310 patients with urticaria seen over 32 years found the prevalence of DPU to be 2%. [19]

The peak age of onset of DPU is in the 20s and 30s (range, 5-63 y). [20] DPU is slightly more common in men than in women.

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Prognosis

Delayed pressure urticaria (DPU) is a chronic disease that can last for years (mean, 9 y; range, 1-40 y). [20] One study reported that 28% and 48% of patients with DPU were free of lesions after 5 and 10 years, respectively. The morbidity of DPU varies, depending on the severity and the response to treatment. In some patients, this condition can be disabling, especially in patients who perform manual labor.

Quality-of-life (QOL) tools have demonstrated that patients with urticaria can show impairments in QOL scores similar to those seen in patients with chronic dermatoses such as psoriasis and atopic eczema. QOL scores were lowest for energy, social isolation, emotional reaction, and sleep disturbance. [21]

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