Allergy overview

Allergy and atopy

• Response to foreign substances need immune system

• Immune response is normal in healthy people

• Immune system response is exaggerated in allergic patients which lead to damage body tissues

Allergy overview

Allergy and atopy

Exaggerated immune response in allergic patients

produce ↑ IgEs (type 1 hypersensitivity)

Allergy overview

Allergy and atopy

• Atopy is the tendency to develop an exaggerated IgE response, as reflected by +ve SPT to one or more common allergens (i.e. a predisposition to develop allergic disease)

• Allergy is the clinical expression of atopy (i.e. the symptoms). Symptoms depend on the target organ. For example, allergy affecting the lungs causes allergic asthma, allergy affecting the nose causes AR

Allergy overview

Allergy and atopy

• Many people are atopics but don’t have allergic symptoms

• Atopics may or may not develop allergic symptoms later

Allergy overview

Allergy and atopy

• We don’t know how atopics become allergics

• If we know it will be easy to interrupt this process to avoid atopics to develop allergy – but we don’t

Allergy overview

Types of allergy

Allergic manifestations are several according to the system

involved like:

• asthma

• rhinitis

• atopic dermatitis (eczema)

• acute Urticaria – Angioedema

• food allergy

• anaphylaxis

Allergy overview

Types of allergy – asthma - 4 cardinal symptoms

• Cough

• chest tightness

• wheeze

• breathlessness

Allergy overview

Types of allergy – rhinitis

• sneezing, runny and itchy nose

• seasonal (hay fever)

• perennial (all the year)

• often together with allergic conjunctivitis (red itchy watery eyes)

Allergy overview

Types of allergy – AD (eczema)

• allergy in skin

• itching + redness + scaling, weeping and thickening of the skin

• anywhere but more in face, scalp, flexures of (elbows, knees and wrists)

Allergy overview

Types of allergy – Acute urticaria

• allergy in skin

• skin redness and itch followed by hives (red swollen area)

• hives initially red then pale

Allergy overview

Types of allergy – Acute urticaria

• this reaction is called "nettle rash" as it resemble a nettle sting

• Angioedema is form of urticaria that manifests as swelling

of face and mouth

Allergy overview

Types of allergy – food allergy

• GIT → diarrhea, nausea, vomiting

• out side GIT → Urticaria, eczema, asthma and anaphylaxis

Allergy overview

Types of allergy – anaphylaxis

• Sudden, sever, generalized allergic reaction

• Itching, angioedema, bronchospasm, sever drop in BP with vascular collapse and shock

Allergy overview

Allergens

Wide spectrum of allergens

Allergy overview

Allergens

1. airborne (aeroallergens)

2. contact allergens

3. ingested allergens

Allergy overview

Allergens – HDM

• tiny, spider-like (its not insect)

• live on flakes of:

• human skin

• house dust

• fungal spores

• pollen grains

• plant fibers and insect scales

Allergy overview

Allergens – HDM

• invisible to naked eye

• People become allergic to its protein in their droppings

Allergy overview

Allergens – HDM

• All houses are infested

• Highest concentration in:

1. mattress

2. pillows

Allergy overview

Allergens - HDM

People are exposed to high levels because:

• most of them spend most of their time indoor (poor ventilation)

• many hours in bed

Allergy overview

Allergens – pollen

• small size pollens distributed by wind to great distances

• So…….symptoms can be caused by local exposure or even great distance away

Allergy overview

Allergens – pollen

• grass (timothy grass, ryegrass)

• tree (birch, hazel, London plan)

• weed pollen (mugwort)

Allergy overview

Allergens – pets

Allergen exposure either

• airborne allergy

• contact allergy

Allergy overview

Allergens – cats

• commonest cause of pet allergy

• allergens mostly found in saliva → so allergen reach fur during grooming and licking → when dry can shed to air for hours or days

Allergy overview

Allergens – dogs

• cause allergy in similar way

• dog allergy less common than cats

Allergy overview

Allergens – moulds

• aspergillus fumigatus, cladosporium and alternaria alternata

• less common cause of allergy

• types: - indoor moulds in damp house

- outdoor moulds

Allergy overview

Allergens – true food allergy

• Rare

• milk, wheat, egg, peanut and shellfish

Allergy overview

Epidemiology of allergic diseases

• Epidemiology: the study of the occurrence, distribution and causes of diseases

• Prevalence: number of cases present at a given time per 1000 or 100000 of population

• Incidence: number of new cases occurring within a defined time period (eg. A year) per 1000 or 100000 of the population

Allergy overview

Epidemiology – prevalence

• 15 – 20 % in UK

• More in younger people

• >50 y the prevalence is lower

Allergy overview

Epidemiology – prevalence

Hayfever prevalence is

- 16% in 15 – 24 years

- then decline after this age (Wuthrich 1998, LAIA

1998)

Allergy overview

Epidemiology – prevalence

Prevalence of allergic diseases is increasing (asthma,

eczema, hayfever)

Allergy overview

Epidemiology – prevalence of atopy

• Prevalence of atopy is increasing

• there is increasing prevalence of sIgE to common aeroallergens in children (in 2 studies in Switzerland and Japan)

• Increase +ve SPT in adults living in London in 1974 compared with those in 1988 (sibbald et al 1990)

Allergy overview

Epidemiology – prevalence of hayfever

Four-fold increase number of summer consultations

(seasonal) between 1950 - 1980

Allergy overview

Epidemiology – prevalence of asthma

Prevalence is increasing about 70% from 1974 to 1986

(Lewis et al 1996)

Allergy overview

Epidemiology – prevalence of eczema

Substantial increase in reporting mothers that their child (5

-7 years) had eczema since 1964 (Taylor et al 1984)

Allergy overview

Epidemiology – prevalence of allergic contact dermatitis

Prevalence constantly changes as the allergen come and go

Allergy overview

Epidemiology – prevalence of food allergy

• Prevalence difficult to determine because of population misbelieve

• 20 % of population think they have food allergy BUT <2% of adults have it

Allergy overview

Epidemiology – prevalence of food allergy

Increased prevalence of peanut prevalence in UK

• 1,2 % had +ve SPT to food at 4 years (Tariq et al 1996)

• Sampson 1997

• 44% of children with moderate to sever atopic dermatitis have +ve SPT to peanut between 1981 to 1985

• but in 1994 increases to 68%

Allergy overview

Epidemiology – prevalence of anaphylaxis

• At 1940s it was mainly to penicillin

• Recently its mainly to latex (gloves) in medical procedures (Dillard and McCollum 1992)

Allergy overview

Risk factors

• FH of allergy or atopy

- if one parent has allergy there is 25 – 30% chance the child will have

- if both parents have allergies chance increase to 50 – 80%

• smoking

- maternal smoking during pregnancy

- paternal smoking during childhood

Allergy overview

Risk factors

• lifestyle (diet, socioeconomic status and housing environment)

- lower prevalence in eastern than western countries in adults (Jogi et al 1998)

- lower prevalence of asthma and atopy in children in east Germany compared to west Germany (Braback et al 1994, Nowak et al 1996)

Allergy overview

Risk factors

• age and environmental factors

- <3years → childhood asthma

-later in childhood → other atopic disorders

Allergy overview

Risk factors – factors which decrease risk

• Being breastfed for at least 16 weeks

• Some infections

Allergy overview

Mortality

Inspite allergy isn’t fatal disease but mortality still present:

• 1600 die from asthma each year in UK

• anaphylaxis, urticaria, angioedema can be fatal (very rare)

- death due to penicillin anaphylaxis only 1/7.5 million injections (Idose et al 1968)

- venom anaphylaxis 1/6.5 million stings (Parrish 1965)

- 4 death's/year due to peanut

Allergy overview

Mortality

Improvement in population awareness of anaphylaxis and its

management is necessary

Morbidity

Allergies cause

• considerable suffering

• and medical treatment costs

Allergy overview

Allergy overviewMorbidity – rhinitis

We think its trivial problem but it causes considerable

morbidity

Allergy overview

Morbidity – rhinitis

1. widespread morbidity

2. reduced work productivity

3. lost school days

Allergy overview

Morbidity – rhinitis

4. significant effect on life quality

- Fatigue

- headache

- impaired thought process

- discomfort from itchy, watery eyes and nose

Allergy overviewMorbidity – rhinitis

5. sedating antihistamines (Vuuman et al 1993, O'Hanlon and Ramaekers 1995)

- affect mental performance

- car accidents

- accidents at work

- ↓ work productivity

- impaired school performance

Allergy overview

Morbidity – asthma in children

• many hospital admissions

• absence from school (NAC 2000)

Allergy overview

Morbidity – asthma

• in elderly more likely to report poor general health, depression, limitation of daily activities (Enright et al 1999)

• physical and emotional distress

• occupational asthma → change job

• affect career, sport enjoyment, sexual relations

Allergy overview

Morbidity – eczema

• particular problem in children

• 90% before 5years

• Considerable distress due to (itching, soreness)

• Constant scratching leave skin open to infection

Allergy overview

Morbidity – acute urticaria

• Nettle rash cover large areas

• In sever reactions → dramatic drop in BP, loos consciousness

Allergy overview

Morbidity – acute urticaria

Physical urticaria lead to sever limitation in lifestyle like:

• Prevent them leaving house on hot or cold days

• swimming in cold water

• bathing in hot water

• wearing tight cloth

Allergy overview

Morbidity – chronic Urticaria

Cause mostly unknown

Allergy overview

Morbidity – food allergy

• serious life restriction because its difficult to identify which food contain the trigger

• full food components (list) usually not clear in many places (ex: restaurants, take away shops)

Allergy overview

Morbidity – food allergy

Peanut allergy

• small amount can cause anaphylaxis

• this cause life distress

Allergy overview

Gap in provision of allergy care in UK

• inspite large numbers of cases the service is very little

• allergy isn’t part of any undergraduate curriculum in medical schools

• limited postgraduate opportunity

Allergy overview

Gap in provision of allergy care in UK

• few specialist allergy clinics

• mostly in south east (Respiratory alliance 2003)

• referrals and waiting lists to these centers vary

(3month – 2 years)

• one allergist/2.1 million while one chest physician/100,000

Allergy overview

Gap in provision of allergy care in UK

• allergy treated according to organ most affected inspite allergics suffer from more than one system

- children with sever rhinitis usually associated with wheezing

- children with eczema may suffer asthma or anaphylaxis to peanut

Allergy overview

Gap in provision of allergy care in UK

charities must fill the gap:

• British allergy foundation

• NAC

• Anaphylaxis campaign

• National eczema society

Allergy overview

Gap in provision of allergy care in UK

• These charities provide helplines and information for allergy sufferers

• Unfortunately there is "alternative practice" with no evidence tests (ex: analysis from hair sample) by unqualified people with high prices

Allergy overview

Gap in provision of allergy care in UK

• NHS developed guidelines, setting out the standards of allergy care (RCP et al 1995)

Allergy overview

Gap in provision of allergy care in UK

Contents of this guideline:

- It shows which conditions need allergy care

- allergic child should be under pediatrician care because

progression in this age is different from adults

- the pre-requisites of allergy clinics in hospitals

Allergy overview

Improving standards of patient care in UK

• BSACI distribute one specialist allergy clinic for each region

• Each clinic have:

- 2 full time allergists

- full time specialist nurse

- half-time dietician with interest in allergy

- one full time specialist registrar in allergy

Allergy overview

Improving standards of patient care in UK

• improving the allergy practice in primary care

• using modern management approaches which can control most types

• giving more time for (patients assessment, full history, education, FU)

• training health professionals

Allergy overview

Improving standards of patient care in UK

• SPT is under-used because of:

- many health professionals think its time consuming

-historical reasons of decline of immunotherapy

-perceived lack of need for accurate allergy diagnosis

Allergy overview

Improving standards of patient care in UK

• Medications care:

- how to use (inhalers, nasal spray)

- written notes

• setting up allergy clinics

- by expanding existing asthma clinic

- or open new allergy clinic

Allergy overview

Improving standards of patient care in UK

• appreciate regional considerations like increase of occupational allergy in certain region because of the presence of factory in that area

Allergy overview

Gap in provision of allergy care in Saudi

• Allergists have to do something to cover this gap!!!

• Tell now there is no Saudi allergy society??!

• One of the most important missions of AAG is to try to cover this gap

?

Allergy overview

Saudi allergy and clinical immunology society (SACIS)

Is it Possible

??