Urticaria, angio-oedema and anaphylaxis

Abstract

Urticaria, angio-oedema and anaphylaxis are distinct clinical entities caused by transient plasma leakage from small blood vessels. When the affected vessels are superficial the result is a raised, itchy swelling of the skin known as a weal. Involvement of deeper vessels produces tender subcutaneous and submucosal swellings known as angio-oedema. Generalised plasma exudation leading to shock is a feature of anaphylaxis but also occurs in anaphylactoid reactions and the capillary leak syndrome. DefinitionsUrticaria is an eruption of transient superficial itchy weals, pale or pink in colour which may have a surrounding flare of redness. They may be few in number or numerous and widespread. Their size varies from a few millimetres to many centimetres. The hallmark of urticaria is its rapid fluctuation. Individual lesions come and go within 24 hours, but the eruption of fresh weals means that the whole attack may last much longer.Urticarial lesions (ie areas of superficial swelling) are also seen in skin diseases other than urticaria (eg some drug reactions, bullous pemphigoid). In these conditions, the lesions do not show the rapid fluctuation which characterises urticaria. They will not be considered further in this article.Angio-oedema implies deeper vascular leakage producing swellings predominantly affecting the subcutis. They tend to be large, pale and painful rather than red and itchy, and last longer than weals. Angio-oedema is a cause of distressing oropharyngeal swellings but may occur anywhere on the integument including the genitalia.Anaphylaxis is defined by a life-threatening fall in blood pressure, difficulty with breathing or both. Other features, including widespread redness, itching and urticaria may occur (Table 1). True anaphylaxis is due to an allergic reaction involving allergen-specific immunoglobulin (Ig) E. Anaphylactoid reactions present similarly but do not involve IgE. Classification of urticaria and angio-oedemaIt is helpful to divide urticaria into different clinical categories for the purpose of management. Many acute cases are short-lived or episodic but recurrent urticaria that continues at least twice a week for over six weeks is defined as chronic.The simplest working classification is to separate urticarias into four categories (Table 2): ordinary physical vasculitic urticaria (urticarial vasculitis) contact urticaria.Angio-oedema may be a feature of most patterns of urticaria and, for the most part, can be considered together with urticaria. However, it is worth considering angio-oedema separately when it occurs without weals (Table 3) because it may then be a presentation of C1 esterase inhibitor (C1 inh) deficiency or a drug reaction. Ordinary urticariaOrdinary urticaria is a useful collective term for all recurring urticarias that do not fall into the other three categories, in that they:do CME DermatologyThe common clinical feature of ordinary urticaria is that individual weals last less than 24 hours before disappearing completely without residual colour or texture change ...

Clinical similarities among bradykinin‐mediated and mast cell‐mediated subtypes of non‐hereditary angioedema: a retrospective study

“…It is deliberately not based on biochemical mechanisms because of a lack of evidence on this topic. These subgroups are in line with previous literature [2–4,6], although different classifications are sometimes used [14].…”

“…Angioedema (AE) is caused by a rapid local increase in permeability of capillaries and venules with subsequent extravasation of fluid into the interstitial space, which becomes clinically manifest as self-limiting, localized subcutaneous or submucosal swellings. AE is classified into several subtypes [ 1 - 3 ]. The first step in the classification is to differentiate AE with wheals from AE without wheals.…”

“…AE with wheals can be diagnosed as chronic spontaneous urticaria (CSU) or chronic inducible urticaria (CINDU), and is presumably mast-cell mediated [ 2 ], although treatment with (high doses of) antihistamines does not always lead to complete symptom relief [ 4 ]. AE may occur in all forms of CSU and CINDU, except dermographism [ 3 ]. It can be caused or aggravated by medical drugs such as NSAIDs and antibiotics [ 2 , 5 ].…”

“…ACEi causes AE which is presumably bradykinin‐mediated and is more closely related to hereditary angioedema (HAE) than the other forms [6]. Finally, idiopathic AE is diagnosed when all other causes have been excluded [2–6]. Idiopathic AE can be either histaminergic or non‐histaminergic, based on the response to antihistamines [6].…”

Acquired cold urticaria symptoms can be safely prevented by ebastine

“…Urticaria is a common skin condition with a wide range of subtypes. It is characterized by the rapid appearance of wheals and sometimes angioedema (1–3). The wheals are associated with an itching or burning sensation, while the angioedema is sometimes painful rather than itchy.…”