Chronic urticaria and angioedema

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Also refer to National Patient Pathways and British Association of Dermatology guidance and patient information leaflet.

Preparations used in the management of serious acute allergic emergencies are listed in section 3.4: for guidance on their use refer to Resuscitation Council algorithms.

Urticaria and angioedema are caused by similar mechanisms and their management is essentially the same.  This section is the view of the Dermatology Department, Raigmore Hospital and only a brief guide to initial management.

Physical urticarias (eg cold urticaria) are less common than ‘ordinary’ urticaria, however patients with physical urticaria often suffer from ‘ordinary’ urticaria whealing and/or angioedema as well.

Urticaria is artificially divided into ‘acute’ and ‘chronic’; the former lasting less than 6 weeks, the latter longer.

Investigations and associations

A careful history is most important, particularly precise details of attacks, symptoms, signs, and general health and activities immediately before attacks. It is especially helpful to seek:

  • a history of atopic problems
  • a detailed drug history, including OTC and ‘alternative’ preparations (see triggering factors, below)
  • effect of anxiety/stress, infections, arthritis/inflammatory disease, thyroid disease, menstruation.

Urticaria, especially chronic urticaria, is relatively rarely an ‘allergic’ phenomenon; a specific allergic cause is usually obvious from a careful history.

Once acute or episodic urticaria has resolved, investigation is unlikely to yield any useful information.

Investigations
  • Undertake the following in all chronic urticaria patients: U&E, LFT, TFT, FBC, ESR, C-reactive protein, autoantibodies, complement profiles.
  • The following tests are seldom appropriate and are expensive:
    • C1 esterase inhibitor is only helpful in cases of suspected ‘hereditary’ angioedema (very rare).
    • IgE and RAST profiles seldom yield useful information in the absence of clear clinical suspicion/evidence of a specific sensitivity. By definition, atopic patients nearly always have elevated IgE levels and often multiple positive RASTs to common inhalants and food atopens. Patch testing is inappropriate.
Triggering factors

The following often worsen/precipitate attacks in a non-specific, ‘pharmacological’ fashion, rather than being due to ‘allergy’: 

  • Alcohol, caffeine, aspirin and other related NSAIDs, codeine and other opiates and OTC preparations containing them. They should be sought in the history (above). Paracetamol is the analgesic of choice in urticaria patients and seldom causes problems.
  • Junk foods containing preservatives, flavourings and colouring materials may cause ‘pseudo allergic’ flares of urticaria/angioedema, as can foods containing high levels of salicylates.
  • Any prescriber looking after a patient with urticaria/angioedema should be informed of the presence of this reaction pattern. Exercise caution with exposure to the drugs/substances listed above and especially to opiates (including general anaesthetics) and some iodine-based radiographic contrast media. Also avoid ACE inhibitors and angiotensin-II receptor antagonists until urticaria has settled for at least 6 months.
Treatment
  • Start with a non-sedating antihistamine. Most agents help within 2 weeks but overall adequacy of control by an individual agent should not be judged for 6 weeks. 
  • The first-line non-sedating antihistamine in NHS Highland is cetirizine:
  • Systemic steroids are definitely a third-line agent for severe urticaria/angioedema only and should be used in conjunction with antihistamines.  They are often complicated by tachyphylaxis/rebound; always taper slowly. A sensible starting dose would be 20 to 30mg once daily, tapering by 2·5mg/day once or twice per week down to 10mg once daily then reducing at the rate of 2·5mg each week. If systemic steroids are required for more than 4 weeks consider referral. As with most inflammatory dermatoses, excessively fast withdrawal of systemic steroids is often followed by rebound which may be severe and worse than the original condition.
  • Subcutaneous adrenaline (Epipen®) is only very rarely indicated.
Natural history
  • Chronic idiopathic urticaria and physical urticarias usually run a waxing/waning course of months to years before settling spontaneously, usually after 9 months to 2 years.
  • Treatment is aimed at control, not necessarily eradication.
  • Classical triggers (listed above) should be avoided in all cases, however a specific ‘allergy’ or an associated problem is usually not found.
  • Disease impact studies in recent years have shown that chronic urticaria is as disabling/upsetting to patients as moderate to severe angina.
Editorial Information

Last reviewed: 31 December 2016

Next review: 31 December 2018

Author(s): Skin Review Group

Version: 8

Approved By: high-uhb.tam@nhs.net