Urticaria and Angioedema

Introduction

Urticaria is a superficial swelling of the skin that results in a red, raised, itchy rash. Angio-oedema is a deeper form of urticaria with swelling in the dermis and submucosal or subcutaneous tissues¹.

Urticaria and angioedema may be allergic or non-allergic (spontaneous).  In spontaneous urticaria/angioedema there may be exacerbating factors (E.G. heat, cold, pressure, stress, some medications).

 

In Scope  

• Adults (16 years and over) with chronic urticaria and/or angioedema

 

Not in Scope    

• Airway compromise with angioedema +/- urticaria, see anaphylaxis
• Acute urticaria (less than six weeks)
• Atopic eczema
• Suspected food or drug allergy
• Recurrent sensation of isolated throat swelling without other features of allergy – consider alternative diagnosis (E.G. Globus sensation)

 

Red Flags

• Airway compromise with angioedema +/- urticaria, treat as anaphylaxis and follow emergency treatment
• Hereditary/acquired angioedema

Patients with isolated angioedema with no history of urticaria raises the possibility of hereditary/acquired angioedema.

 

Management Optimisation

In the absence of red flags above, follow the steps below:

History:

• Thorough history to include
  • Date of onset
  • Nature and severity of symptoms
  • Exacerbating factors (E.G. heat, cold, pressure, stress, medications)
  • Treatment required and efficacy
  • Thorough assessment to exclude underlying pathology (E.G. chronic infection)
  • Suspected triggers (likely only if the symptoms are predictably associated with exposure, and remit upon avoidance. If the symptoms persist despite avoidance the suspect can be excluded as a cause.)

 

Acute Management (without red flag features)

• Spontaneous urticaria and angioedema, in the absence of requiring emergency management, should be treated initially with non-sedating antihistamines.
  • Higher than licensed doses may be required¹. This advice can be found on CKS here. This is supported by British and European guidelines with good safety data
  • These increased doses must not be used in pregnancy¹, and attention paid to interactions with other drugs
  • Patients with ongoing symptoms (rash or swelling) despite high dose four times daily¹ prophylaxis with non-sedating antihistamines, consider adding Montelukast+/- H2 antagonist in addition to antihistamines
• Swelling involving the mouth/tongue can cause patient’s considerable concern. If tongue swelling is mild, and there are no red flag concerns, and patient is not responding to high dose antihistamine, consider a short course of oral steroids as per CKS¹. Local advice suggests considering prednisolone15-20mg OD for up to three days. (longer courses can lead to refractory worsening symptoms)

 

Medication Review

• Patients with urticaria and/or angioedema should be advised to use NSAIDS with caution as these can exacerbate Chronic Spontaneous Urticaria (CSU). DPP4 inhibitors (‘gliptins’) can also be associated with angioedema⁴
• ACE inhibitor treatment can cause angioedema² (without urticaria) even after months or years of treatment and must be stopped in patients presenting with angioedema. All patients with angioedema should avoid ACE inhibitors³, as well as related drugs such as neprolysin inhibitors (E.G. sacubitril in Entresto).

 

Further management information found on NICE CKS Urticaria

 

Advice and Guidance

No advice and guidance service is available

 

Investigations required prior to referral

No investigations required prior to referral.

The exception to this is for patients with isolated angioedema with no history of urticaria. Consider hereditary/acquired angioedema. Check complement C4 prior to referral. If low refer to the allergy service urgently.

 

Referral Criteria

Urgent Referral

• Angioedema without urticaria and a low C4

 

Routine Referral

• Urticaria and/or angioedema persisting for 3 months or more despite 4 x daily non-sedating antihistamine and montelukast
• History of cold inducible urticaria
• Angioedema on ACE-I medication
  • Stop ACE-I. Refer if symptoms persist for a further 3-4 months after stopping, and despite four times daily non-sedating antihistamines and montelukast.
• Diagnostic uncertainty

 

Referral Instructions

GPs continue to have the right to refer via referral letter in the usual way.

There is a referral form available, which would help to minimise returned referrals. This is currently available on the DRSS Urticaria Page under their referral section. Only the relevant section needs to be completed.

 

Useful Information

 Patient

• Hives (Urticaria): Causes, Symptoms, and Treatment
• British Association of Dermatologists
• Urticaria and Other Skin Allergy | Allergy UK | National Charity

 

Professional

• referral form (found under the referral section on the linked page)
• Eden Unit GP Information | University Hospitals Plymouth NHS Trust
• Scenario: Managing urticaria | Management | Urticaria | CKS | NICE
• Non-sedating antihistamines | Prescribing information | Urticaria | CKS | NICE
• ACE inhibitor-induced angioedema

 

References

1. Urticaria | Health topics A to Z | CKS | NICE
2. Angiotensin-converting enzyme inhibitors | Prescribing information | Hypertension | CKS | NICE
3. Scenario: Angio-oedema without anaphylaxis | Management | Angio-oedema and anaphylaxis | CKS | NICE
4. https://www.bsaci.org/resources/allergy-management/drug-allergy/non-steroidal-anti-inflammatory-drugs-nsaids/

 

Page Review Information

Review date:                     03 June 2025

Next review date:              03 June 2027

Speciality Lead GP:          Dr Kate Northridge

Contributors:                      Dr Catherine Elliott, Specialist Doctor in Allergy, University Hospital Plymouth