1. Referral Guidelines for Allergy in General Practice

2. Allergy in 10 minutes DETECTIVE WORK Presenting episode
Previous episodes
Consistent trigger or pattern to episodes
Contacts/Foods in previous 4 hours (most begin within 30 minutes)
Co-factors - exercise/alcohol/NSAIDS/intercurrent illness
Other drugs
Atopic medical history - CONCURRENT ASTHMA
Assess severity

3. GRADING SYSTEM FOR GENERALISED HYPERSENSITIVITY REACTIONS
GRADE
Brown et al 2006 1
MILD
Skin and subcutaneous tissues only:
Generalised erythema, urticaria, periorbital oedema or angioedema 2
MODERATE
Respiratory, cardiovascular or gastrointestinal symptoms:
Dyspnoea, stridor, hoarseness, wheeze
Nausea, vomiting
Dizziness (presyncope), diaphoresis
Chest or throat tightness, abdominal pain 3
SEVERE
Hypoxia, hypotension or neurological compromise:
Cyanosis or SpO2≤92%
Systolic blood pressure<90mmHg in adults
Confusion, collapse, loss of consciousness

4. Management of Anaphylaxis
RESCUE KIT:
MILD: Anti-histamine high dose
MODERATE: ADD Soluble prednisolone 30mg (0.5mg/kg)
SEVERE: ADD Adrenaline auto injector
300mcg/500mcg over 30kg
150mcg 15-30kg

5. Anaphylaxis Refer suspected severe anaphylaxis symptoms:
Any combination of:
Bronchospasm
Laryngeal/pharyngeal oedema
Hypotension
USUALLY with flushing, urticaria, angioedema
If blood sample taken:
Gold top marked: ‘HOLD- allergens to be advised’

6. Urticaria & Angioedema
Non –allergic cause suggested if:
Spontaneous/overnight/early morning
Physical triggers
Several days duration
No consistent relationship with food (ingestion/contact)
In Food Allergy:
Symptoms usually within 30 minutes of ingestion
Delay of more than 2 hours is rare
ACE-I with angioedema

7. Lots of guidelines…

8. Definition Urticaria Wheals Mediated by histamine ‘Hives’
‘Nettle rash’
Wheals
Central swelling of variable size with reflex erythema
Associated with itching (or sometimes burning)
Fleeting nature, lasting 1 – 24 hours
Mediated by histamine

9. Definition Angioedema Mediated by bradykinin (also histamine)
Sudden, pronounced erythematous or skin-coloured swelling of lower dermis, subcutis and below mucous membranes
Sometimes pain rather than itching
Slower resolution, up to 72 hours
Mediated by bradykinin (also histamine)

10. Treatment: Angioedema with or without urticaria
Rx as for urticaria
Check not on ACE-I
Isolated angioedema:
check C3, C4, C1-inhibitor and electrophoresis
If intraoral swelling:
Add soluble prednisolone 30mg as stat PRN dose
Consider need for adrenaline auto-injector
REFER

11. Epidemiology Common – lifetime incidence of urticaria is 20%
30% of these go on to experience prolonged symptoms
Can occur at any age
40% urticaria only
50% urticaria and angioedema
10% angioedema only

12. Quality of life issues Can significantly affect QOL
Affects both objective functioning and subjective well-being
Work
Education
Social aspects
Comparable health status scores to patients with coronary artery disease
Guidelines recommend objective QOL measures

13. Classification Acute <6 weeks Chronic >6 weeks Spontaneous
Triggers
Allergy
Medication e.g. NSAIDs, oestrogens
Infections
Chronic >6 weeks

14. Classification of chronic urticarias
Chronic spontaneous urticaria
Previously ‘idiopathic’ or ‘ordinary’ urticaria
Stimuli mostly unknown
NOT allergy
Chronic inducible urticarias
Symptomatic dermographism
Cold urticaria
Pressure urticaria
Solar urticaria
Heat urticaria
Vibratory angioedema
Cholinergic urticaria
Aquagenic urticaria
Contact urticaria

15. Diagnosis
History is very important

16. Investigations Acute spontaneous urticaria
No routine diagnostic tests recommended
Extended testing only if strong suggestion from history e.g. allergy
Chronic spontaneous urticaria
Routine: FBC, ESR or CRP
Omit suspected drugs (e.g. NSAIDs)
Extended testing based on history
Infectious disease, Type I allergy, TFTs and thyroid antibodies, skin tests, low pseudoallergen diet, tryptase, skin biopsy, autoantibodies against IgE receptor, ANA, complement
Inducible urticarias
Physical provocation tests e.g. ice cube test for cold urticaria

17. Management
Aim of treatment is complete symptom relief as safely as possible
2nd generation antihistamines
cetirizine, loratadine, fexofenadine
(desloratadine, levocetirzine, rupatadine, bilastine)
Short course of steroids (up to 10 days maximum) for acute urticaria or acute exacerbations
Long term treatment not recommended
Same treatment algorithm for children
Acute urticaria is self-limiting
Need for treatment may vary with time (step up step down)

18. Management Avoidance of triggers
Medication
Physical factors (for inducible urticaria)
Dietary manipulation
Food allergy is very rare
Patients with known food sensitisation should only avoid if there is clear history or relevant test e.g. food challenge to show that it is relevant to urticaria
Low pseudoallergen diets
Limited evidence
Recommended by European guidelines, but not in American guidelines
Long list of medicines with little evidence have been tried
H2 antihistamines (although recommended in American guidelines)
Nifedipine
Warfarin
Dapsone
Hydroxychloroquine
Sulfasalazine
Methotrexate
Mycofenolate
Colchicine
IVIG
Azathioprine

19. Interactions with other medicines
First-generation antihistamines
Alcohol
Night sedatives
Benzodiazepines
Tricyclic antidepressants
Monoamine oxidase inhibitors
Second-generation antihistamines
Most second-generation antihistamines do not have important interactions
Rupatadine  - antibiotics (minocyclines) or grapefruit juice
Mizolastine  - nifedipine , cimetidine  and ciclosporin 
Third generation
Fexofenadine ketoconazole erythromycin

20. Side effects First-generation antihistamines
Common:
drowsiness (should not be underestimated)
dry mouth
dizziness
constipation
blurred vision
urinary retention
Less common:
insomnia 
nightmares
hallucinations
itchy skin
Rare:
palpitations
chest tightness

21. Side effects Second-generation antihistamines
Less common: (usually pass)
drowsiness
headache
dry mouth
dry nose
Rare:
palpitations
chest tightness
Third-generation antihistamines
Similar to second-generation
drowsiness (less common than with first-generation antihistamines)
nausea
Do not carry the same risk of arrhythmia

22. Low pseudoallergen diet
Diet needs to be followed for 3 weeks

23. Management of isolated angioedema
‘Idiopathic’
ACE inhibitors
Should be stopped
Can cause angioedema
Can worsen angioedema due to other causes
Occurs even after a few years on medication
Can take several months for effect to wear off even after stopping medication
ARBs can be used in place if needed
Small chance of swelling with ARB as well
C1 inhibitor deficiency
Hereditary angioedema (HAE)
Acquired angioedema
Very rare
Low C4
Reduced C1 inhibitor levels and/or function

24. Summary Urticaria/angioedema is common
Can have profound impact on quality of life
Acute urticaria rarely needs investigating unless suggested by history
Chronic urticaria is almost never due to allergy
Usually chronic spontaneous, or inducible
Aim of treatment is complete symptom relief - NO wheals, swelling or itch
First line treatment is 2nd generation antihistamines
Standard dose, can be increased up to 4x
Stop ACE inhibitors in angioedema

25. Hay fever Start 2 weeks prior to earliest symptoms
Continue daily treatment throughout season
‘Itchy –Sneezies’: Potent antihistamine up to 2 bd
Nasal congestion: Intranasal Steroids up to 2 bd
Ocular symptoms: opticrom/optilast
Consider montelukast
REFER: Rescue steroids/SLIT/IT

26. Eczema in Adults
Adult patients often keen to find a dietary allergic cause
Many demonstrate apparent sensitisation
Routine blood testing not advised in the absence of symptoms of food allergy
Contact eczema: Skin PATCH testing- Dermatology

27. SUMMARY: When to Refer Insect venom anaphylaxis
Symptoms do not respond to treatment/avoidance
Confirmed IgE mediated food allergy with asthma
Tests are negative but a strong suspicion of allergy
Anaphylaxis of uncertain cause
Review of condition/for retesting/management