History and Examination

The clinical history of the symptoms and suspected precipitants/exacerbating factors is paramount, along with examination of the symptoms if possible.

The history should 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).
  
• If associated with airway/breathing/circulation/neurological features see anaphylaxis guideline
• If history suggests food or drug allergy (in the absence of anaphylaxis) please click for appropriate guideline (drug allergy and food allergy).

ACE inhibitor treatment can cause angioedema (without urticaria) even after months or years of treatment and must be stopped in patients presenting with angioedema.

Angioedema in the absence of urticaria also raises the possibility of hereditary/acquired angioedema; check complement C4 to exclude this.

No investigations are routinely indicated, and should only be performed if there is a specific indication. The exception is complement C4 levels in angioedema alone.

1. Spontaneous urticaria and angioedema should be treated initially with oral non-sedating antihistamines.
   1. Treatment may be as required or prophylactic depending on symptom frequency of symptoms.
   2. It is common practice for dermatologists to titrate non-sedating antihistamines to 2-3 times the licensed doses if tolerated.
   3. These increased doses must not
      be used in pregnancy, and attention should be paid to interactions with other drugs.
2. Swelling involving the mouth/tongue can cause patients considerable concern. If tongue swelling is mild treatment with additional antihistamine and a single dose of prednisolone 20-30mg may be used.
   1. Long term regular corticosteroids are not
      advised.
3. Any systemic involvement (e.g., airway, breathing, circulation, neurological) prescription of 2 x 0.3mg self-injectable adrenaline pens, instruction in their use, and be referred to a specialist allergy service.
   1. All patients must have appropriate training in use of self-injectable adrenaline.
      
   2. Please see 3.4.3 Allergic emergencies for Formulary Guidance is available at including links for educational materials (including how-to videos, guides, trainer pen ordering, expiry alert service, etc)
4. All patients with angioedema should avoid ACE inhibitors, as well as related drugs such as neprolysin inhibitors (e.g., sacubitril in Entresto).
5. Patients with urticaria and/or angioedema should be advised to use NSAIDS with caution as these can exacerbate CSU. DPP4 inhibitors can also be associated with angioedema.

Referral Criteria

1. Patients with troublesome symptoms (rash or swelling) despite high dose four times daily prophylaxis with non-sedating antihistamines.
   1. Montelukast 10mg daily (unlicensed) +/¬- H2 antagonist may be tried in addition to antihistamines.
2. Any systemic features to suggest anaphylaxis (link to anaphylaxis guideline).
3. Patients with angioedema on ACE-I medication; stop ACE-I - if symptoms persist 3-4 months after the ACE-I has been stopped and despite four times daily non-sedating anti-histamines, refer to the Peninsula Specialist Immunology and Allergy Service’
   
4. If there is diagnostic uncertainty
5. Recurrent sensation of isolated throat swelling without other features of allergy - consider alternative diagnosis (e.g., globus, vocal cord dysfunction) and consider ENT referral.
   
6. Patients with angioedema without urticaria and a low C4
7. Periorbital oedema with eczema/dry skin rash – consider periorbital eczema and referral to Dermatology for patch testing.

Referral instructions

Refer to Clinical Immunology Service

• Refer using e-Referral Service
  • Specialty: Allergy
  • Clinic type: Allergy
  • Service: DRSS-Eastern-Allergy-Devon ICB- 15N

Referral form

DRSS Referral form

GP Information

Formulary guidance: Management of urticaria

Devon Formulary guidance - antihistamines

onlinelibrary.wiley - guideline for the management of chronic urticaria and angioedema

Patient Information

Chronic urticaria (Hives)

Pathway Group

This guideline has been signed off on behalf of NHS Devon.

Publication date: March 2016

Updated: September 2023