What is the Difference Between Urticaria and Angioedema?

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Urticaria and angioedema are both skin conditions that involve swelling, but they have distinct differences:

  • Urticaria: Also known as hives, urticaria consists of discrete areas of skin edema that are usually pruritic (itchy). These lesions can vary in size and may appear anywhere on the body, but they are not painful. Urticaria typically lasts less than 24 hours and leaves no residual skin markings upon resolution. It can be acute (lasting less than 6 weeks) or chronic (lasting 6 weeks or more).
  • Angioedema: This condition involves the deeper dermis and subcutaneous tissue, presenting as localized areas of soft tissue swelling. Angioedema is not typically itchy but can produce an uncomfortable burning sensation and may be painful. It primarily affects the face, lips, mouth, upper airway, genitals, and extremities. Angioedema may occur with or without urticaria and can be drug-induced, hereditary, or acquired.

In some cases, urticaria and angioedema occur together, with 49% of patients experiencing both conditions, 40% experiencing urticaria alone, and 11% experiencing angioedema alone. Diagnosis for both conditions is typically based on patient history, physical examination, and laboratory investigations.

Comparative Table: Urticaria vs Angioedema

Urticaria and angioedema are both skin conditions that can present together or separately. Here is a table comparing the differences between the two:

Feature Urticaria Angioedema
Definition Urticaria, also known as hives, is a common disorder characterized by recurrent, pruritic (itchy), pink-to-red edematous (swollen) lesions that often have pale centers (wheals). Angioedema is an acute condition manifesting as localized edema affecting the skin and mucous membranes. In contrast to urticaria, itching is often absent, the skin appears normal, and the edema occurs in deeper dermal and subcutaneous tissues.
Symptoms Urticarial lesions are polymorphic, round or irregularly shaped pruritic wheals that range in size from a few millimeters to several centimeters. They can develop anywhere on the body and are spread by scratching, combining into large, fiery-red patches. Angioedema is characterized by nonpitting, non-pruritic, well-defined, edematous swelling that involves subcutaneous tissues (e.g., face, hands, buttocks).
Etymology The term "urticaria" comes from the Latin word "urtica," meaning "nettle". The term "angioedema" comes from the Latin words "angio," meaning "vessel," and "oedema," meaning "swelling".
Classification Urticaria is classified as acute (lesions for < 6 weeks), chronic (lesions > 6 weeks), or physical (lesions result from a physical stimulus). Angioedema can be divided into histamine-mediated and non-histamine-mediated types.
Diagnosis The diagnosis of urticaria, with or without angioedema, is based primarily on a thorough clinical history. Diagnostic tests may be helpful in some instances. Distinguishing between histamine-mediated and non-histamine-mediated angioedema is crucial for proper diagnosis and management.
Treatment Treatment for urticaria often includes second-generation, non-sedating antihistamines. Treatment for angioedema depends on the type and underlying cause, and may include medications that target histamine or bradykinin pathways.