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Urticaria

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Urticaria\: skin condition with itchy, raised wheals (hives) lasting minutes to 24 hours.
Angioedema\: deeper swelling involving periocular skin, lips, or genitalia, lasting up to 72 hours.
Acute urticaria\: sudden onset, often self-limiting, lasts up to 6 weeks, may be triggered by infection or medication.
Chronic urticaria\: recurrent wheals lasting >6 weeks, can be spontaneous (idiopathic) or inducible (triggered).
Pathophysiology\: mast cell-driven, histamine release increases capillary permeability causing oedema and wheals.
Common triggers\:
Aquagenic\: water exposure.
Cholinergic\: warmth or exercise.
Cold\: cold exposure.
Heat\: heat exposure.
Dermatographism\: skin pressure.
Pressure\: sustained pressure.
Solar\: UV radiation.
Vibratory\: vibratory stimuli.
Contact\: skin contact with allergens.
Risk factors\: female sex, age 20-40, atopy, chronic stress, family history.
Symptoms\: itchy, raised wheals, lesions may be round or ring-shaped, last 1-24 hours, can be recurrent.
Diagnosis\: clinical, based on history and appearance. Provocation testing for inducible urticaria.
Di
pemphigoid.
Investigations\:
Acute urticaria\: no investigations needed.
Chronic urticaria\: FBC, ESR, provocation testing for inducible urticaria.
Management\:
Lifestyle modi
Medical management\:
First-line\: oral second-generation H1-antihistamines (cetirizine, levocetirizine, desloratadine, fexofenadine).
Second-line\: increase antihistamine dose fourfold if needed.
Severe
Specialist treatments\: omalizumab, ciclosporin, Urticaria Activity Score (UAS) and Dermatology Life Quality Index (DLQI) for
monitoring.
Complications\: impacts quality of life, disrupts sleep, can cause anxiety or depression, interferes with daily activities.
Prognosis\: generally good with appropriate management, many cases are self-limiting or respond well to treatment.
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Introduction

Urticaria is a skin condition characterised by the sudden appearance of itchy, raised wheals (hives), mainly in the upper
dermis, which can characteristically last between a few minutes to 24 hours.
Angioedema
Urticaria can co-exist with angioedema, a deeper swelling within the deep dermis, subcutaneous tissue and/or
mucous membranes.
Although angioedema can occur anywhere, it characteristically involves the periocular skin, the lips and/or the
genitalia. Its resolution is typically slower than wheals (hives), lasting up to 72 hours.
1

Aetiology

Types of urticaria

Urticaria can be broadly classi
Acute urticaria\: sudden onset of wheals, at times associated with triggers such as infection or medication. It is often self-
limiting, with symptoms resolving within a few hours to days. In total, it lasts up to 6 weeks.
Chronic urticaria\: Persistent or recurrent wheals lasting for more than six weeks. Chronic urticaria can be spontaneous
(idiopathic) or inducible (caused by a known trigger).
Figure 1. Classi
2

Pathophysiology

Urticaria is predominantly a mast cell driven disease. Mast cells are activated by various signals (including autoantibodies
and cytokines) and release histamine.
Histamine causes an increase in the permeability of local capillaries and small venules. The increased permeability results
in oedema of the upper and mid-dermis, giving the typical itchy, red-raised wheel appearance in urticaria.
1
Urticaria is commonly idiopathic, meaning it has no speci
Inducible urticaria, on the other hand, occurs only when a trigger is present (Table 1).
Table 1. Triggers for chronic inducible urticaria.
1
Subtype Trigger identi
Aquagenic urticaria Exposure to water, be it hot or cold
Cholinergic urticaria
Active or passive warming (e.g. from exercise or
emotional upset)
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Cold urticaria
Exposure of skin to cold (such as swimming in cold
water)
Exposure of skin to a heat source
Heat urticaria Symptomatic
dermatographism
Delayed pressure
urticaria
Solar urticaria Shearing force acting on the skin
Vibratory angioedema
Contact urticaria Sustained pressure (e.g. after sitting or lying, or due
to tight clothing)
Exposure to UV radiation
Exposure to vibratory stimuli (such as use of power
tools)
Skin contact with an o
However, some patients with spontaneous urticaria report trigger-induced wheals or angioedema. Triggers can include
NSAIDs, aspirin, tight clothing, heat or a particular food item. These triggers are, however, not de
symptoms can occur in the absence of such triggers, and their presence may not always induce signs and symptoms of
urticaria.

Risk factors

Urticaria can occur in the absence of risk factors. However, risk factors that can predispose an individual to an increased
risk of urticaria can include\:
3,4
Female sex
Age between 20 - 40
Atopy
Chronic stress
Family history

Clinical features

Urticaria causes highly pruritic raised skin rash with lesions that may be round or ring-shaped.
Lesions often become con
completely. The diagnosis of urticaria is clinical, based on the history and appearance of the rash.
In active urticaria, a typical urticarial rash will have three main features\:
1
Central raised swelling of variable size and shape surrounded by an area of erythema
Associated pruritus
A

History

Important areas to cover in the history include\:
Time of onset
Nature, duration, pattern and frequency of the rash
The presence of itching (typically, pruritus is stimulated by skin contact and patients can complain that scratching will
increase the itchiness of the rash)
Possible triggers or causes (to determine if the condition is spontaneous or inducible)

Clinical examination

Due to the
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Patients may bring photos of their rash, which can help make the diagnosis. Urticarial rashes are seen as raised swellings of
variable size and shape surrounded by erythema.
Figure 2. Typical urticarial lesion.
5
Figure 3. Urticaria on trunk.
6
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Figure 4. Urticaria on dark skin.
7
Inducible urticaria can be con
the patient may reveal dermatographism, which is seen as a linear wheal and
stimulus.
8

Di

Urticaria is often a straightforward diagnosis, but di
Scombroid
Urticarial vasculitis
Hereditary angioedema
Pre-bullous stage of bullous pemphigoid

Investigations

Acute urticaria is self-limiting, and therefore, investigations are not usually required.
In chronic urticaria, no investigations are routinely required. A full blood count and ESR can be considered, which may be
abnormal in urticarial vasculitis and autoin
In chronic inducible urticaria, provocation testing may be performed to con
Patch testing
Patch testing is unsuitable for investigating urticaria, as it is designed to detect type 4 delayed cell-mediated
eczematous hypersensitivity reactions. In contrast, urticaria typically results from type 1 hypersensitivity reactions,
which are immediate and involve IgE antibodies and mast cells.

Management

Management aims to control symptoms to achieve a normal quality of life and prevent recurrence.

Lifestyle modi

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In spontaneous urticaria, lifestyle modi
and tight clothing. Cooling the skin, for example, using a cold
symptoms.
In inducible urticaria (where there is an identi
1
Symptomatic dermographism\: reduce friction and avoid tight clothing
Cold urticaria\: dress warmly in cold or windy conditions and avoid swimming in cold water
Delayed pressure urticaria\: broaden the contact area, for example, of a heavy bag or using a seatbelt cushioned cover
Solar urticaria\: wear long-sleeved clothing, avoid peak sun hours and apply broad-spectrum sunscreens

Medical management

Oral second‐generation (non-sedating) H1‐ antihistamines are used as the
Examples include cetirizine, levocetirizine, desloratadine, and fexofenadine.
1,9
Start at a standard dose of one tablet daily in adults and reassess every 2-4 weeks (
the dose can be increased fourfold (second-line).
One type of antihistamine can be switched to another if there is a poor response or the medication is not tolerated.
A short course (up to 10 days) of oral prednisolone can be added for symptom control in severe urticarial 9,10
term steroids are not recommended. Topical steroids are of no use.
Long-
If symptoms do not settle with antihistamines, the patient should be referred appropriately for specialist care.
Specialist treatments
Further treatment escalation should only be initiated by a specialist.
Examples of such treatment can include omalizumab (anti-IgE monoclonal antibody) and ciclosporin (calcineurin
inhibitor).
9
Validated tools such as the Urticaria activity score (UAS) or the Dermatology Life Quality Index (DLQI) can help monitor
disease activity and assess the e
11,12

Complications

Urticaria can greatly a
on both the daily activities and emotional well-being of patients’ lives.
Urticarial symptoms, especially pruritus, can disrupt sleep, be a source of anxiety or depression and can interfere with
performance at work or school.

Prognosis

The prognosis for urticaria is generally good, especially with appropriate management. Many are self-limiting or respond
well to treatment. However, a minority of chronic cases require long-term treatment.

References

National Institute for Health and Care Excellence. U r t i c a r i a . Published in 2023. Available from\: [LINK]
Dermnet. Adapted by Geeky Medics. ClassiCC BY-SA]
Sánchez-Borges, M., Ansotegui, I. J., Baiardini, I., e t a l . The challenges of chronic urticaria part 1\: Epidemiology,
immunopathogenesis, comorbidities, quality of life, and management. Published in 2021. Available from\: [LINK]
Hon, K. L., Leung, A. K. C., Ng, W. G. G. and & Loo, S. K. (2019) Chronic Urticaria\: An Overview of Treatment and Recent
Patents. Published in 2019. Available From\: [LINK]
Dermnet. Urticarial rash dark skin. Licence\: [CC BY-SA]
Dermnet. Typical Urticarial lesion. Licence\: [CC BY-SA]
Dermnet. Urticarial lesion on trunk. Licence\: [CC BY-SA]
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Nobles, T., Muse, M. E., & Schmieder, G. J. Published in 2023. Available from\: [LINK]
Sabroe, R.A., Lawlor, F., Grattan, C.E.H., Ardern‐Jones, M.R., Bewley, A., Campbell, L., Flohr, C., Leslie, T.A., Marsland, A.M.,
Ogg, G., Sewell, W.A.C., Hashme, M., Exton, L.S., Mohd Mustapa, M.F. and Ezejimofor, M.C. (2021). British Association of
Dermatologists guidelines for the management of people with chronic urticaria. Published in 2021. Available from\: [LINK].
Dermnet. U r t i c a r i a – a n o v e r v i e w . 2021 Available at\: [LINK]
MDcalc. Urticaria severity score. Available at\: [LINK]
AY Finlay, GK Khan. Dermatology Life Quality Index (DLQI)--a simple practical measure for routine clinical use. Published in
1992. Available from\: [LINK]

Reviewer

Dr Daniel Micallef
Dermatology registrar

Acne vulgaris
Basal Cell Carcinoma (BCC)
Cellulitis
Cutaneous Squamous Cell Carcinoma (SCC)
Erythema Multiforme

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