Pets and Asthma -Sept 2010 by wpr1947


									    Pets and Asthma
   what do we know,
what should we know and
 what should we advise?

          Chris Doyle
        Nurse Consultant
       Asthma & Allergy
  Alder Hey Children's NHS FT
                                Sept 2010
Cats and Dogs
    In UK approx. 16 million cats
    & dogs

    10 Million children
    7% children are sensitised to

    4% children are sensitised to

          Sadeghnejad et al Thorax 2004
                   Cats and Dogs
60% of asthmatics show  IgE to cat &/or dog allergen

1/3rd of asthmatics live with a pet cat &/or dog

Sensitisation to cats is a major risk factor for asthma

Individuals an become sensitised even if they have never
lived with pets

Early sensitisation is associated with more severe disease
    Sensitisation to pets is a risk factor
    for hospital admission with asthma
%     60                                     hopsital
      50                                     admission
      40                                     stable asthma
      20                                     Control
           cat   dog   mite   Any allergen

                                               Murray et al Thorax 2006
               Cat Allergen - Fel d 1
– Fel d 1 responsible for 90% of cat specific IgE
– Allergenic activity present in dander, pelt & urine
– Produced in sebaceous and salivary glands
– Cats can produce 3-7 mcgs day
– Fel d 1 higher in male cats
– Castration of male cats lead to a 3-5 fold reduction
      in Fel d 1
              Cat Allergen - Fel d 1
– Small, lightweight sticky allergen <5um diameter

– After disturbance remains airborne long
– Easily respirable
– Easily transferable
– Pet allergens found in huge concentrations in houses
      with pets
– levels of pet allergen found in homes with no
      pets, public transport, hospital OPD‟s
Homes with pets have >100 fold higher allergen
  levels on surfaces than homes with no pets
  Cat Allergen in Homes With and Without Cats
  Fel d 1 (µ g/g)






           Mattress         Bedroom      Living room      Uphd.
                             carpet        carpet        furniture
                      Homes with cats   Homes without cats

                                                       Custovic, Thorax 1998;53:602-607
            Cat Allergen in Public Places
      Fel d 1 (µ g/g)



      Carpets Seats Carpets Seats       Carpet    Seats Mattress Carpets        Seats
         Public         Cinema                     Hotel              School    Public
         Houses                                                                Transport
                  Custovic et al Clin Exp Allergy 1996; 26: 1246-52
 Cat Allergy - Sphinx Cat ($1000)
          All cats have dander –
          there is no safe breed!

                       Not so cute !
Effect of Washing the Cat on Airborne Cat Allergen


         ); or mg/100ml H2O (   60




      Fel d 1 ng/m3 (


                                 0                                         De Blay et al,
                                 Wash # 1   Wash # 2   Wash # 3   Wash # 4 ARRD 1991; 143:
                                  (Day 0)    (Day 7)   (Day 14)   (Day 21) 1334-1339
What about washing the cat?

                      Wash pet and pet
                      bedding weekly
DBPC trial of environmental control in the
        treatment of cat allergy
   – HEPA room air cleaner
   – Mattress & pillow covers
   – Cat exclusion from the bedroom
   – Some reduction in airborne Fel d 1
   – No difference between groups in any
     of the clinical outcomes

          Wood RA et al, Am J Respir Crit Care Med 1998; 158: 115-20
Effect of Removing Cat

Wood RA et al, Am J Respir Crit Care Med 1998; 158: 115-20
        What about mans best friend?
               Dog Allergen
                 (Canis Familiaris)
Allergenic activity in dander, pelt hair and
saliva (not in urine)

Major allergen Can f 1, produced in salivary

89-90% of dog allergic subjects have IgE to
Can f 1
Cute…. but hypoallergenic?
                Are all dogs equal?
– Varying degrees of Can f 1 amongst all dogs        (1)

– No totally non-allergic dogs
– Some do cause fewer allergies
   – Smaller dogs produce less saliva
   – Shed less fur/dander
   – Some breeds require freq bathing/grooming
   – Washing dogs does cause a reduction in allergen
      levels – back to starting levels within 3 days

                                        (De Groot et al JACI 1991)
       Avoiding cat & dog allergens
                        Reduce     Gives
                       airborne   clinical
                       allergen    benefit

Pet in situ:
      Wash pet                       ?
      Remove carpets                 ?
      HEPA                           ?
      Castration                     ?
Removal of pet                       
       So we have established that….

Pets are common

Sensitisation to pets is a risk factor for asthma

Pet allergen is ubiquitous, easily transferable and
easily respirable
            ‘Paws’ for thought…….
Allowing cats in bedroom in 1st yr. of life prevents
development of childhood asthma (Orbele et al 2003)

Early exposure to cats increases risk of developing
asthma in adolescence and adult life (Wahn et al 1997)

Dog owners are at reduced risk for allergic sensitisation
                                               (Simpson 2006)

Pet keeping neither favors nor protects from allergic
disease in childhood (Apelberg et al 2001)
  Frequently asked questions
during Asthma & Allergy clinics
               Question 1

How can I stop my child becoming allergic to
– Don‟t Know

– Can become sensitised even if you don‟t live
  with pets

– No evidence supporting hypoallergenic breeds
                  Question 2
We have 2 cats and 1 dog. My 7 year old daughter
is sensitised to both and my Dr. tells me she is on
is on „Step 3 of the BTS guidelines‟.

How can I improve her asthma control?
– Get rid of the pets

– Allergen levels will fall faster if you get
  rid of the carpets
           Question 3
I love my 3 pet cats and my 2 schitzu
dogs and would rather get rid of the
children, what can I do?
   Pet Allergen Avoidance with Pet in situ
Three studies have addressed pet allergen control
measures in pet-sensitised pet owners.

   – Two showed small improvements in asthma related
     outcomes but one did not

   – Cochrane - no beneficial effect of pet allergen
     control measures for allergic asthma in children and

              Francis 2003,van der Heide 1999, Wood 1998, Kilburn 2003
             Practical Advice
If child sensitised - best remove offending pet !
Can take months or yrs to  allergen levels
Keep pets out of living areas & bedrooms, off
Remove carpets - replace with vinyl/wooden
Use a vacuum cleaner with a HEPA filter
Fit allergen-impermeable bedding covers
Wash pet and pet bedding weekly
All pets have dander - no safe breed
                Question 4
– Can getting a dog prevent our children from
  developing allergies?

– If so which type of Dog?
– Don‟t Know

– Don‟t Know
       Case Study 1- Kathryn – 14 yrs
Referred to Resp Clinic May ‟08
Diagnosed age 3 yrs. usually well controlled
Increasing asthma symptoms past 12 months
Daily cough, worse at night, worse with URTI‟s,
frequently wheezy, now has exercise limitation and
now missing lots of school
4 A&E visits in past 18 months
5 courses of prednisolone – always help
No eczema          Now has “hay fever all year”
        Case Study 1- Kathryn – 14 yrs
DHx         Becotide 200 BD & Salamol 50 BD
            Salbutamol – “using lots”
FHx         No Asthma/No Allergies
            10yr old sibling with Type I Diabetes
SHx         No Smokers No Damp         18 mo. old dog.
O/E         Slight wheezy      LFT FEV1 78%
            Nasal passages inflamed      CXR Normal
Changed to Seretide 50/25 2 puffs BD
AMP & inhaler technique checked
       Case Study 1- Kathryn – 14 yrs
4 month review
IgE 350 >100 to Dog (neg to all else)
Very symptomatic, no great improvement, still missing
GP had recently increased Seretide to 125/25 2 puffs BD
Bi lateral wheeze   FEV1 68%
Mum refused to consider removal of dog but would no
longer allow it upstairs
10 mgs Cetirizine daily
     Case Study 1- Kathryn – 16yrs
2 yrs. on
4-6 monthly review
Still symptomatic
Frequent exacerbations
Added in Montelukast (Step 3 of BTS Guidelines)
FEV1 at last visit 66%
„Strained relationships within family‟
Dog still in home
Kathryn waiting to leave home
                 In Summary
– Sensitisation to pets is a risk factor for asthma

– Can become sensitised even if you have never
  lived with pets

– Patients who are sensitised and exposed have
  more severe asthma

– Pet sensitised, pet exposed asthmatics with
  symptoms should part with their pets!
              Many thanks to

            Dr Angela Simpson
          University of Manchester
University Hospital of South Manchester NHS
              Foundation Trust
“OK, where‟s that nurse that works in the
           allergy clinic”?

            Any Questions?

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