• Determine whether this is the first episode of urticaria or a recurrent/persistent presentation.
• Assessment should involve:
• The exclusion of angio-oedema (admission is needed if there is airway involvement). For more information, see the CKS topic on Angio-oedema and anaphylaxis.
• Confirmation of the diagnosis of urticaria, and if possible identification of the cause.
• If it is the first presentation of urticaria:
• Reassure the person that acute urticaria is normally self-limiting, and is not serious or infectious.
• Offer a non-sedating oral antihistamine (e.g. cetirizine, fexofenadine, or loratadine).
• Consider an additional sedating antihistamine at night if the itch is interfering with sleep.
• Consider an additional short course of oral prednisolone (e.g. 40 mg daily for 3–5 days) for generalised acute urticaria.
• Follow-up is needed only if symptoms have not improved or are worsening.
• If urticaria is persistent (chronic urticaria):
• Advise the person about self-care and avoiding known trigger factors.
• Continue treatment with a non-sedating antihistamine, or consider switching to a different one.
• Consider an additional sedating antihistamine at night if the itch is interfering with sleep.
• Topical menthol 1% cream can be used instead of, or in addition to, oral antihistamines.
• Consider a short course of oral prednisolone (e.g. 40 mg daily 3–5 days) to control severe flare-ups.
• Follow-up will depend on the frequency and severity of attacks.
• Refer persistent urticaria (usually lasting beyond 6 weeks) that is still troublesome despite antihistamines, or is thought to be related to vasculitis or an acute allergy (e.g. peanut or latex).

• Confirm the diagnosis and try to identify the underlying cause considering:
• Timing of episodes (seasonal, perennial, nocturnal), geography (work, home, school), and environment (pets, smoking).
• Drugs, including over-the-counter medicines.
• Family history of urticaria or autoimmunity.
• Recent travel, viral illness, or insect bites. For more information, see the CKS topic on Insect bites and stings.
• Relationship to foods, occupation, and physical triggers.
• Systematic enquiry, including ENT (ear, nose and throat) problems (e.g. rhinitis), gastrointestinal problems (diarrhoea, malabsorption), autoimmune disorders (diabetes, thyroid), atopy, and skin disorders.
• Assess the severity of the episode:
• Examine the ears, nose, and throat; listen to the person's chest; and measure blood pressure and pulse to exclude angio-oedema and anaphylaxis with systemic involvement, which needs urgent admission to hospital. For more information, see the CKS topic on Angio-oedema and anaphylaxis.
• Investigations are not usually required.

• These recommendations are pragmatic advice based on expert opinion from the medical literature [Grattan et al, 2001; Kozel and Sabroe, 2005].
• Investigations such as a radioallergosorbent test (RAST) or skin prick test are generally only undertaken by secondary care.
• Depending on local policy, a RAST and/or a skin prick test should only be carried out where there is a clear link to a specific food or other agent (e.g. latex).
• RAST is only useful for IgE-mediated reactions. These are more likely to be environmental triggers (e.g. latex, nuts). RAST is not useful for physical stimuli (cold, heat) or certain drug-reactions caused by a non-IgE-mediated mechanism.
• Skin prick tests expose the person to an allergen extract and measure the size of the response (flare/weal) to help confirm or exclude an allergy to a specific allergen. However, the correlation between a positive skin prick test and the likelihood of developing a reaction on exposure to the allergen is not absolute [Berger, 2002].
• Both tests can result in false-positive and -negative results.

• Treatment is not needed if the episode is mild; acute urticaria is normally self-limiting, and is not serious or infectious.
• If symptomatic treatment is needed:
• Offer a non-sedating antihistamine to control daytime symptoms.
• Consider giving an additional sedating antihistamine at night if the itch is interfering with sleep.
• For severe symptoms:
• Give a short course of oral corticosteroids (e.g. prednisolone 40 mg daily for 3–5 days) in addition to the oral antihistamine.
• If rebound symptoms occur after a short course of corticosteroids seek specialist advice. Repeat courses of steroids are not recommended.

Oral antihistamines:

• Antihistamines (H₁-receptor blockers) are the only drugs licensed for use in urticaria.
• In people with chronic urticaria, randomized controlled trials of non-sedating antihistamines have reported improvements in symptoms of itch, weal formation, frequency of exacerbations, and quality of life [Belaich et al, 1990; Breneman et al, 1995; Kaplan et al, 2005; Zuberbier et al, 2006].
• Although the efficacy of antihistamines has only been demonstrated in chronic urticaria, there is a consensus that they are also effective for acute urticaria: urticaria of all types is characterized by histamine release [Grattan et al, 2001; Zuberbier et al, 2006].

Oral corticosteroids:

• Experts recommend that a short course of high-dose oral corticosteroids should be reserved for severe acute urticaria [Grattan et al, 2001].
• Corticosteroids are potent immunosuppressants and can therefore suppress the symptoms of urticaria. However, CKS found only one non-randomized, open study (prednisolone 50 mg daily for 3 days) that examined their use [Zuberbier et al, 1996]. This study found that a 3–day course of oral prednisolone followed by loratadine shortened the duration of acute urticaria compared with loratadine treatment alone.
• In view of the lack of prospective studies of oral corticosteroids for urticaria, CKS recommends a 3–5 day course of oral prednisolone, at the same dosage as used for an acute exacerbation of asthma [SIGN and BTS, 2005].
• CKS does not recommend repeat courses of oral corticosteroids for rebound symptoms because of concerns that this will lead to their long term use, and because of the risk of potential adverse effects.

• Mild cases of acute urticaria will not normally require any follow-up.
• Advise people with acute urticaria to return if:
• Their symptoms worsen.
• There is no response to treatment after 2 weeks; try an alternative non-sedating antihistamine or reconsider the diagnosis.
• If symptoms recur or persist for more than 6 weeks (and still need medication to control them), consider referring to an immunologist or dermatologist for further management.
• Any suggestion of angio-oedema will require admission or a daily review until the symptoms have resolved. For more information, see the CKS topic on Angio-oedema and anaphylaxis.

• This is pragmatic advice based on expert opinion from the medical literature [Grattan et al, 2001].
• Individuals vary in their response and tolerance to antihistamines. Therefore a switch in non-sedating antihistamine is useful if there is no response (e.g. within 2 weeks) to the initial antihistamine [Grattan et al, 2001; Zuberbier et al, 2006].
• Non-sedating antihistamines are routinely increased beyond the recommended licensed dose in secondary care to control symptoms [Grattan et al, 2001; Zuberbier et al, 2006]; however, this is likely to increase the risk of adverse effects and there are few trial data that evaluate this approach. CKS recommends that it is not advisable to increase above the maximum dose, unless the healthcare professional has experience in doing so, or before seeking specialist advice.

• Confirm the diagnosis of chronic urticaria (symptoms recur or persist for more than 6 weeks).
• Although not always possible, try to identify the underlying cause using a detailed history and examination, considering:
• Timing of episodes (seasonal, perennial, nocturnal), geography (work, home, school), and environment (pets, smoking).
• Drugs, including over-the-counter medicines.
• Family history of urticaria or autoimmunity.
• Recent travel, viral illness, or insect bites. For more information, see the CKS topic on Insect bites and stings.
• Relationship to foods, occupation, and physical triggers.
• Systematic enquiry including ENT (ear, nose, and throat) problems (e.g. rhinitis), gastrointestinal problems (diarrhoea, malabsorption), autoimmune disorders (diabetes, thyroid), atopy, and skin disorders.
• Consider the following investigations:
• Full blood count (FBC) looking for iron, B₁₂ and folate deficiency, and eosinophilia of intestinal parasite infection and some drug-induced reactions.
• Stool sample (if intestinal parasites suspected).
• Erythrocyte sedimentation rate (ESR) — raised in vasculitic urticaria, chronic infection, and autoinflammatory syndromes.
• Thyroid function tests (including autoantibodies).
• Liver function tests and H. pylori screening if gastrointestinal symptoms are present.
• Identify any ongoing trigger factors.
• Assess the severity of symptoms and their impact on daily living and psychological well-being.
• Itch in chronic urticaria is seen by most people as moderately or very troublesome. It may occur during the day and at night [Yosipovitch et al, 2002].
• Consider referring people to an immunologist or dermatologist, depending on local policy.

• These recommendations are pragmatic advice based on expert opinion from the medical literature [Grattan et al, 2001; Kozel and Sabroe, 2005].
• Investigations are not usually helpful for identifying the underlying cause of chronic urticaria. However, there is some evidence to suggest that basic tests (e.g. FBC, stool sample, ESR, TFTs), in combination with a good history, are just as effective at identifying the cause as an extensive laboratory screen [Leznoff and Sussman, 1989; Kobza-Black and Champion, 1998; Kozel et al, 1998; Wanderer et al, 2000]. For example, a low haemoglobin concentration may suggest a chronic disorder as an underlying cause of chronic urticaria.
• A radioallergosorbent test (RAST) is not usually needed, as allergy is only a rare cause of chronic urticaria [Wanderer et al, 2000].

• Manage any underlying associated diseases (e.g. H. pylori infection, thyroid disease, connective tissue disorder), although there is no strong evidence that correcting these conditions will improve the urticaria itself.
• Offer a non-sedating antihistamine to control daytime symptoms.
• Consider giving an additional sedative antihistamine at night if the itch is interfering with sleep.
• Topical menthol 1% cream can be used as an alternative to, or in addition to, an oral antihistamine.
• For a severe 'flare up', give a short course of oral corticosteroids (e.g. prednisolone 40 mg daily for 3–5 days) in addition to an oral antihistamine.
• If rebound symptoms occur after a short course of corticosteroids seek specialist advice. Repeat courses of steroids are not recommended.

• In chronic urticaria, there is wide variation in the disease and in the response to treatment. Management aims to improve quality of life by avoiding trigger factors, and to use medication to reduce the severity and frequency of symptoms [Grattan et al, 2001; Zuberbier et al, 2006].

Oral antihistamines:

• Antihistamines (H₁-receptor blockers) are the only drugs licensed for use in urticaria.
• Histamine is one of the primary mediators of urticaria.
• In people with chronic urticaria, randomized controlled trials of non-sedating antihistamines have reported improvements in symptoms of itch, weal formation, frequency of exacerbations, and quality of life [Belaich et al, 1990; Breneman et al, 1995; Kaplan et al, 2005; Zuberbier et al, 2006].
• Non-sedating antihistamines are routinely increased beyond the recommended licensed dose in secondary care to control symptoms [Grattan et al, 2001; Zuberbier et al, 2006], however this is likely to increase the risk of adverse effects and there are few trial data that evaluate this approach. CKS recommends that it is not advisable to increase above the maximum dose, unless the healthcare professional has experience in doing so, or before seeking specialist advice.

Oral corticosteroids:

• Long-term use of oral corticosteroids for chronic urticaria is not recommended because they have significant adverse effects (e.g. adrenal suppression) [Grattan et al, 2001; Kozel and Sabroe, 2005]. Short tapering courses of oral steroids over 3–4 weeks may sometimes be used. However, there is no consensus in the medical literature about which regimen to use and when to use it [Kozel and Sabroe, 2005], so this type of treatment is best guided by specialists.
• CKS recommends that short courses of high-dose oral corticosteroids should be reserved for severe flare-ups of urticaria, particularly while awaiting referral.
• In view of the lack of prospective studies of oral corticosteroids for urticaria, CKS recommends a 3–5 day course of oral prednisolone, at the same dosage as used for an acute exacerbation of asthma [SIGN and BTS, 2005].
• CKS does not recommend repeat courses of oral corticosteroids for rebound symptoms because of concerns that this will lead to their long term use, and because of the risk of potential adverse effects.

Menthol 1% cream:

• Menthol 1% in aqueous cream is cooling and is reported to soothe itch [Greaves and Sabroe, 1998; Grattan et al, 2001]. One small study in 15 healthy volunteers found that a menthol 1% (in ethanol) solution successfully relieved histamine-induced itching [Bromm et al, 1995].

• Identify and avoid trigger factors.
• Reduce complications of excessive scratching by keeping nails short and clean, and by rubbing the skin with the palms of the hands if necessary.
• Choose clothing that does not irritate the skin (e.g. cotton).
• Consider whether certain skin creams, soaps, or detergents are making symptoms worse, and use lubricating, alcohol free, hypoallergenic lotions if possible.
• Consider the use of calamine lotion to soothe itch.

• This is pragmatic advice based on expert opinion from the medical literature [Moses, 2003; Kozel and Sabroe, 2005].
• Calamine lotion generally soothes itch [Grattan et al, 2007], although the residue (when dried) can exacerbate itch in some people [BNF 52, 2006].

• Advise people to reduce or avoid factors that are known to exacerbate their urticarial rash, that may include:
• Stress
• Alcohol, caffeine, spices, and hot water
• Some foods (e.g. fish, shellfish, nuts, cheese) and food additives (e.g. dietary salicylates, azo dyes, and benzoic acid).
• Food is often overestimated as a cause — in genuine food allergy, symptoms usually occur reproducibly within 60 minutes of exposure to the offending food. Food diaries may be helpful but can be hard to interpret.
• Overheating — keep the bedroom cool whilst sleeping and avoid hot baths.
• Tight clothing
• Medication — e.g. aspirin, codeine, nonsteroidal anti-inflammatory drugs (NSAIDs), and angiotensin-converting enzyme (ACE) inhibitors. Advise people not to use cold remedies or herbal preparations until the exacerbating factors have been excluded.
• Insect bites and stings — remove the stinger after a bee or wasp sting as soon as possible. Advise people to wear long-sleeved clothing and to avoid wearing bright colours or perfume.

• Stress is an important precipitant of urticaria. In one small non-randomized study, relaxation therapy and hypnosis improved self-reported symptoms but not the number of observed weals [Shertzer and Lookingbill, 1987].
• Diets and food avoidance remain controversial with very little evidence to support their benefit in people with urticaria [Zachariae et al, 1969; Kozel and Sabroe, 2005]. Food can usually be excluded as a cause of urticaria if there is no temporal relationship to a particular food trigger, either by ingestion or contact. In genuine food allergy, symptoms usually occur reproducibly within 60 minutes of exposure to the offending food [Powell et al, 2007].
• Alcohol, caffeine, spices, and hot water all cause vasodilation and may precipitate urticaria [Moses, 2003].
• Overheating commonly exacerbates itch, so advise keeping the bedroom cool at night whilst sleeping, and avoiding hot baths [Moses, 2003].
• Tight clothing should be avoided in delayed-pressure urticaria. This minimizes sweating which is thought to be an important precipitant of the symptom of itch [Yosipovitch et al, 2002].
• Medication — if possible avoid drugs such as aspirin (not contraindicated in urticaria but the reaction is dose-dependent), codeine, nonsteroidal anti-inflammatory drugs (NSAIDs), and angiotensin-converting enzyme (ACE) inhibitors. Advise people not to use cold remedies or herbal preparations until the exacerbating factors have been excluded [BAD, 2006]. For more information, see the CKS topic on Angio-oedema and anaphylaxis.

[Kozel and Sabroe, 2005]

• Advise people to return if:
• Their symptoms worsen.
• There is no response to treatment after 2 weeks; try an alternative non-sedating antihistamine or reconsider the diagnosis.
• If symptoms recur or persist for more than 6 weeks (and are still troublesome despite the use of antihistamines and avoidance of known trigger factors), consider referring to an immunologist or dermatologist for further management.
• Any suggestion of angio-oedema will require admission to hospital or daily review until the symptoms resolve. For more information, see the CKS topic on Angio-oedema and anaphylaxis.
• After a referral, the follow-up of people with chronic urticaria will depend on the severity of symptoms, response to treatment, and impact on daily living.

• This is pragmatic advice based on expert opinion from the medical literature [Grattan et al, 2001].
• Individuals vary in their response and tolerance to antihistamines. Therefore a switch in non-sedating antihistamine is useful if there is no response (e.g. within 2 weeks) to the initial antihistamine [Grattan et al, 2001; Zuberbier et al, 2006].
• Non-sedating antihistamines are routinely increased beyond the recommended licensed dose in secondary care to control symptoms [Grattan et al, 2001; Zuberbier et al, 2006]; however, this is likely to increase the risk of adverse effects and there are few trial data that evaluate this approach. CKS recommends that it is not advisable to increase above the maximum dose, unless the healthcare professional has experience in doing so, or before seeking specialist advice.

• Admit a person with angio-oedema involving the airway and/or anaphylaxis. Start initial treatment with intramuscular adrenaline, if available. See the CKS topic on Angio-oedema and anaphylaxis.
• Refer to an immunologist or dermatologist when there is:
• Urticaria with angio-oedema not involving the airway.
• Acute urticaria which is severe and thought to be due to adverse drug reactions, or food or latex allergy.
• Chronic persistent urticaria (usually lasting beyond 6 weeks) which is troublesome despite the use of antihistamines and avoidance of known trigger factors.
• Vasculitic urticaria: this may be suspected if lesions are persistent and painful.
• Referral will depend on local policy and services available.

• These recommendations are based on pragmatic advice from expert opinion. However, local referral pathways may vary.
• A skin biopsy is essential to confirm the presence of small-vessel vasculitis histologically [Grattan et al, 2007].

• Topical corticosteroids and topical antihistamines should not be used in urticaria.

• In one small study of highly-selected people with chronic urticaria, the application of a potent topical corticosteroid (clobetasol propionate) followed by plastic occlusion resulted in only a short-term improvement of symptoms [Ellingsen and Thestrup-Pedersen, 1996].
• Topical steroids do reduce weal formation, but can lead to adverse effects due to the need for long-term use over a large surface area [Kozel and Sabroe, 2005].
• Topical antihistamines have a risk of sensitization and can result in contact dermatitis [Kozel and Sabroe, 2005; BNF 52, 2006].

• Many of the alternative treatments used in secondary care are based on evidence from poor-quality randomized controlled trials (which had small numbers of participants), uncontrolled trials, or case studies [Zuberbier et al, 2006].
• See Table 1 for an outline of treatments that may be used in secondary care.