GP and Secondary Care Information

Introduction, general allergy information, IgE testing

The Clinical Immunology and Allergy Service based at Leeds Teaching Hospitals NHS Trust provides a service to Primary Care from across the West Yorkshire region. It is staffed by a team of 3 Immunology consultants,1 anaesthetist, 2 specialist trainees, clinical fellows, a specialist doctor, a highly advanced pharmacist, and a team of nursing staff.

The service is divided into:

1. General allergy
   1. Nurse led allergy clinics: simple food allergy, aeroallergy, venom immunotherapy
   1. Skin prick test allergy clinics
   1. Pharmacist/specialist nurse led chronic spontaneous urticaria clinic
   1. Medical general allergy clinics
2. Drug allergy
3. Anaesthetic drug allergy
4. Immunology/immunodeficiency
5. Laboratory Immunology and liaison
6. Autoinflammatory

This guidance has been provided to:

1. identify and manage patients who need urgent referrals
2. Provide advice and guidance for those patients who may be managed in primary care

Contact for clinical advice

There is an on-call registrar and/or consultant available through Leeds Teaching Hospital switchboard for clinical advice 24 hours a day. Between 9-5pm this service is usually covered by a speciality trainee; out of hours a consultant is available.

Referral pathways

Referrals from primary care will be accepted through standard pathways Secondary care can refer patients directly as needed. Written referrals are preferred however referrals from acute attendances will be accepted using the following form:

Secondary care referral form

For drug allergy referrals, the appropriate form must be completed.

These guidelines are a reference for referrers and the Immunology team alike. Referrals are triaged by a Consultant Immunologist. Referrals where the merits of providing a clinical opinion are unclear are discussed amongst the clinical team.

General Allergy

Background

There has been an increase in the incidence of true allergic disorders and in the public perception that allergies can explain a variety of symptoms. In reality, true allergies manifest in a relatively narrowly defined spectrum of clinical signs and symptoms. The clinical immunology and allergy consultant and specialist registrar staff are  available to discuss patients by telephone. These referral guidelines aim to assist care providers in the diagnosis and management of allergic disorders and highlight those situations in which referral or a specialist opinion is recommended.

Useful information for allergy

IgE testing

IgE testing (often known as RASTs tests) are only indicated for type 1 hypersensitivity. i.e. histamine mediated. Type 1 hypersensitivity reactions to aeroallergens which are inhaled cause symptoms of sneezing, nasal congestion, wheeze, rhinorrhoea, and allergic rhinoconjunctivitis.

Aeroallergen sensitisation will not cause symptoms of urticaria and anaphylaxis. However, type 1 hypersensitivity to food allergens (e.g. peanut), can cause symptoms of urticaria, life threatening angioedema, hypotension and fulminant anaphylaxis.

RAST tests are not indicated for any other reason, they are of no value in the management of adult eczema or food intolerances. Testing in these populations may lead to clinically irrelevant positive tests and subsequent patient anxiety and dietary restriction. Ultimately, they can be harmful when inappropriately requested.

We do not encourage use of commercial kits and IgG testing which are often available through non-NHS private providers e.g. York test

Skin prick testing versus patch testing

Skin prick tests are used to assess type I hypersensitivity. Patch tests are used to determine delayed hypersensitivity usually in the context of contact dermatitis. We do not provide a patch test service, where there is a suspicion of contact dermatitis, the referral should be made to a local patch testing service (dermatology).

Anaphylaxis

NICE describe anaphylaxis as

“a severe, life-threatening, generalised or systemic hypersensitivity reaction. It is characterised by rapidly developing, life-threatening problems involving: the airway (pharyngeal or laryngeal oedema) and/or breathing (bronchospasm with tachypnoea) and/or circulation (hypotension and/or tachycardia). In most cases, there are associated skin and mucosal changes.”

As per NICE criteria, 2 x adrenaline autoinjectors should be provided with appropriate training in cases of suspected anaphylaxis whilst the patient is awaiting a specialist opinion. The following Anaphylaxis UK website provides useful patient information regarding adrenaline autoinjector use:

Urticaria and/or Angioedema

Referral Criteria

For the patient to receive the most accurate and timely review, photographs at the time of referral will speed up advice provided and aim to exclude alternative diagnoses. Whilst this is not mandatory, it is encouraged.

Background

Urticaria (also known as nettle rash or hives) is an itchy, erythematous, elevated, well defined and irregularly shaped rash that can occur anywhere on the body and may last from only a few minutes up to twenty-four hours. Rashes with features of blistering, desquamation of the skin or with individual lesions lasting longer than 24 hours are not urticarial and an alternative diagnosis needs to be considered. A dermatology referral may be considered in these circumstances. We do not accept patients affected by pruritis (and no rash) and eczema.

Angioedema is usually (but not always) histamine mediated, in such cases it is usually responsive to antihistamine therapy and is managed like chronic urticaria. In a minority of cases, it may be bradykinin mediated.

Acute urticaria

Only a fraction of acute urticaria is due to a food allergy. Single episodes of urticaria may be the manifestation of a food allergy if there is a clear history of ingestion of an implicated food. More commonly it results from intercurrent viral infection, drug ingestion, particularly with non-steroidal anti-inflammatory drugs or is completely idiopathic. Non-recurring episodes of urticaria are highly unlikely to be due to any type of allergy and the patient should be reassured about this.

An isolated episode of urticaria that has occurred one hour after food ingestion does NOT need to be referred. Patients should be advised regarding antihistamine use. They can be advised to use antihistamines above the licensed dose (see chronic urticaria guidelines) as needed.

Patients should be directed to the following website which provides up to date patient information:

Chronic Spontaneous Urticaria (CSU)

Urticaria which last longer than six weeks is termed chronic spontaneous urticaria, patients should be directed to Urticaria and Angioedema | Allergy UK | National Charity and should be advised that testing for multiple allergies is not going to be of benefit.

Common triggers for chronic urticaria include:

• viral infections

• non-steroidal anti-inflammatory drugs, including over the counter medication

• physical stimuli such as pressure on the skin or changes in temperature

• stress

• additives, preservatives and colourants

Chronic urticaria management in primary care:

• NSAIDs such as Aspirin, Naproxen, Diclofenac, Mefenamic acid and Ibuprofen can exacerbate the condition and therefore should be avoided.
• Pharmacological treatment at this stage consists of appropriate use of antihistamines. We recommend using a licensed dose of non-sedating 2^nd or 3^rd generation antihistamines, for example Loratadine or Cetirizine 10 mg daily. If symptoms persist more than 2 weeks, we would recommend increasing the dose of antihistamines up to 4-times the licensed dose. We generally use either Cetirizine/Loratadine at a dose of up to 40mg daily (20mg BD), or Fexofenadine at a dose of up to 720mg daily (360mg BD) as per British Society of Allergy and Clinical Immunology (BSACI) guidelines.

• If antihistamine treatment has failed, please check haemoglobin, CRP, LFTs, thyroid function, calcium & vitamin D, folate, B12 and ferritin levels. We know that disturbances in any of these can cause or exacerbate disease. You should aim for a ferritin >25 mcg/ml even if not anaemic and treat a vitamin D <70 nmol/l with high dose Colecalciferol as per local guidelines.
• In 80% of patients CSU will go into remission after 6 months, antihistamines can be titrated according to treatment response.
• Referrals where the advice above has not been followed will be rejected.
• If the patient is taking four times a day antihistamine and blood tests have been checked and corrected if applicable, and the patient is still having urticaria, please refer to our service.
• You may also consider adding montelukast 10mg at night.

Cold/heat induced urticaria, solar urticaria and cholinergic urticaria should be managed in the same way as CSU.

The chronic spontaneous urticaria pathway is led by a highly advanced Clinical Pharmacist and senior nurses.  Including photographs of the patient’s rash is extremely helpful and will ensure more accurate triaging and early advice. From July 2025 we will be implementing a new virtual CSU pathway by which patients will be asked to send through photos of their rash and Urticaria Activity Scores.

Angioedema in association with urticaria

Where angioedema occurs in association with urticaria, the management is the same as the mechanism is likely to be histamine mediated. Consider prescribing an adrenaline autoinjector if there is tongue or throat swelling, these cases should be referred on a routine basis.

Patients may find the following websites useful:

Angioedema in isolation on an angiotensin converting enzyme inhibitor (ACEi)

The most common cause of angioedema in isolation is ACEi use, it can occur a number of years after being on the drug. Where a patient is on an ACEi please follow the following advice.

• stop the ACE inhibitor.
• An adverse reaction to ACE inhibitors should be recorded in their drug sensitivities section. Angiotensin II receptor blockers which have less propensity to cause angioedema may be used as an alternative if necessary.
• Angioedema due to ACE inhibitors can continue for a number of months after the drug is stopped. High dose antihistamines such as Cetirizine/Loratadine up to 20mg BD or Fexofenadine up to 360mg BD can be used regularly for symptom control if required.
• We would advise that the patient is reviewed 3 months after the drug is stopped, if at this point they continue to have episodes of angioedema please refer them to the Allergy Clinic.

Angioedema in isolation not on an ACEi

The same advice as CSU applies. However, to exclude hereditary angioedema please send a C3 and a C4 with “angioedema” in the clinical details. In cases where the C4 is low please make an urgent referral so that C1 esterase inhibitor deficiency can excluded.