Two forms of pressure urticaria are recognized: immediate pressure urticaria (IPU) and delayed pressure urticaria (DPU). In IPU, swelling and erythema of the skin begin within minutes of the offending pressure stimulus, versus DPU, which takes 4-8 hours for a reaction to develop.
Lesions in pressure urticaria may last for 8-72 hours, a range that is much longer than that of most other forms of urticaria.
Common triggers of pressure urticaria include walking (sustained pressure on the feet), manual labor (sustained pressure on the hands), sitting (sustained pressure on the buttocks), laying down (sustained pressure on the back), and tight clothing. Pressure urticaria can be extremely debilitating, and it tends to impact quality of life more significantly than most other form of chronic urticaria.
Pressure urticaria is associated with other forms of chronic urticaria, dermographism, and aspirin intolerance. It presents as deep swelling often accompanied by burning, stinging, pain, and dysesthesias at the involved site. Unusual forms may present with only pruritus and/or bullae formation. Systemic symptoms may be present in up to 50% of cases and include fever, chills, joint pain, headache, sweating, and dizziness.
L50.8 – Other urticaria
387787005 – Pressure urticaria
- Angioedema – Urticaria and angioedema share a similar pathogenesis, but angioedema manifests with deeper involvement and also involves the mucosal tissue. Angioedema may involve the skin, larynx, and buccal and gastrointestinal mucosa.
- Urticarial vasculitis – A form of leukocytoclastic vasculitis associated with connective tissue disease and hepatitis C.
- Erysipelas – This is a superficial form of cellulitis caused by group A Streptococcus. Like all forms of cellulitis, erysipelas usually begins as a regional infection; drawing a line along leading edge to monitor for continued direct expansion is used to follow the patient clinically.
- Dermographism – A wheal-and-flare reaction occurring with mechanical distention, usually by drawing on the skin with a finger. It occurs minutes after the manipulation and may be associated with atopic dermatitis.
- Contact dermatitis – This is caused by direct irritation or a hypersensitivity response to a skin contactant. Frequently has sharp circumscription and unusually sharp edges that suggest an exogenous etiology.
- Lymphedema – Unlike pressure urticaria, which waxes and wanes, lymphedema is a persistent impairment of lymphatic drainage that leads to nonpitting edema in the area affected.