Tag Archives: blood tests

Allergy update 2013

Allergy – notes from a recent allergy update course with thanks to Dr Su Li, paediatric consultant @ Whipps Cross.

Useful websites:

www.allergyuk.org – good factsheets on rhinitis, oral allergy syndrome etc.

www.itchysneezywheezy.co.uk is a collaborative project for patients, their parents and health professionals on all aspects of atopic illness.

RCPCH allergy care pathways for health professionals (eczema, anaphylaxis, urticaria, mastocytosis, food, drug and venom allergies etc. etc.)

www.bsaci.org (stores patient management guidelines and has recently been accredited by NICE – milk, nut and penicillin allergy guidelines all currently in progress)

How to make a diagnosis:

1.  Allergy  focussed clinical history

2.  Allergy  tests – tests look at sensitisation not clinical allergy, defines probability of allergy

Skin prick tests

IgE tests

Provocation tests / food challenge

IgE ranges :

 

< 0.35 Grade 0
0.35 – 0.7 Grade 1
0.7 – 3.5 Grade 2
3.5 – 17.5 Grade 3
17.5 – 50 Grade 4
50 – 100 Grade 5
> 100 Grade 6

 

Test equivalence :

Skin prick < 3 mm 3-7 mm >7 mm
IgE < 0.35 0.35 – 50 > 50

 

Probability of allergy :

< 3 mm 3-7 mm > 7 mm
High clinical suspicion Possible allergy Probably allergy Allergic
50:50 Possible allergy Possible allergy Probably allergy
Low clinical suspicion Not allergic Possible allergy Possible allergy

 

If ‘possible allergy’ consider food challenge.

 

Peanut Allergy:

  • Your risk of anaphylaxis to peanut is 1% per year if you have a nut allergy.
  • If you have had anaphylactic reaction, your risk increases to 5% per year, therefore always prescribe Adrenaline Autoinjector (EpiPen).
  • The degree of positivity of a test does not change the risk of anaphylaxis.
  • Your risk of having a peanut allergy is 8 times more if you have a sibling with a nut allergy – consider screening siblings.

Eczema:

  • Common allergens associated with eczema are egg, peanut and cows milk.
  • If you are allergic to egg, consider testing for the peanut and milk as they often co-exist
  • Egg exclusion diets can improve eczema symptoms however there is an increased risk of anaphylaxis if you come into contact with egg whilst on an
    exclusion diet.
  • Consider a food challenge after 1 year as egg allergies often resolve.

Cows Milk Protein Intolerance:

  • This is a non IgE mediated disease, allergy testing will be negative.
  • Typical symptoms tend to be eczema or GI upset including reflux, vomiting, ‘colic’, constipation, loose stools, blood and mucous in stools.
  • Management includes a 2-4 week trial of extensively hydrolysed formula (Nutramigen / Peptijunior) or amino acid formula (Nutramigen AA / Neocate).
  • If breastfeeding, mothers need to go onto an exclusion diet (including soya).
  • Do not use over the counter partially hydrolysed formula milks, these still contain cows milk protein.
  • Refer to a dietician if on an exclusion diet.
  • Consider diagnosis of FPIES (food protein intolerance enteropathy syndrome).
  • Cows milk protein intolerance usually resolves around 14 months of age.
  • At this age, introduce soya milk first. If well tolerated, introduce cows milk.

 

 

NICE on anaphylaxis

With thanks to my colleague, Dr Su Li, for summarising this 2011 NICE guideline for Paediatric Pearls.

Anaphylaxis: assessment to confirm an anaphylactic episode and the decision to refer after emergency treatment for a suspected anaphylactic episode

December 2011

www.nice.org.uk/cg134

Anaphylaxis is a severe, life-threatening, generalised hypersensitivity reaction involving

  • the airway (pharyngeal or laryngeal oedema) and/or
  • breathing (bronchospasm, tachypnoea) and/or
  • circulation (hypotension, tachycardia).

 

There can often be skin and mucosal changes. Patients presenting with these signs and symptoms should be diagnosed as having ‘suspected anaphylaxis’.

Anaphylaxis may be an allergic response that is

  • immunologically IgE mediated (foods, venoms, drugs, latex) or
  • non-immunologically mediated or
  • idiopathic (significant clinical effects with no obvious cause).

 

This guideline does not make any drug recommendations. These can be found at http://www.resus.org.uk/pages/reaction.pdf.

Patient Centred Care

  • Treatment and care should take into account patient’s needs and preferences
  • Patients should have the opportunity to make informed decisions about their care and treatment, in partnership with health care professionals
  • Good communication between healthcare professionals and patients is essential
  • Families and carers should be given the information and support they need
  • Care of young people in transition between paediatric and adult services should be planned and managed according to the best practice guidance described in ‘Transition: getting it right for young people

 

Recommendations

  • Document acute clinical features of the suspected anaphylaxis
  • Record the time of onset
  • Record the circumstances immediately before the onset of symptoms to help identify possible triggers

 

  • Consider taking blood samples for mast cell tryptase if reaction is thought to be immunologically mediated or idiopathic
    • First sample as soon after emergency treatment given
    • Second sample 1-2 hours (no more than 4 hours) from onset of symptoms
    • A further sample may be required at follow up with the allergy specialist to measure baseline mast cell tryptase

 

  • Children who have had emergency treatment should be admitted to hospital under the care of the paediatric team.  The resus council suggests observing the child for a pragmatic (no evidence yet) 6 hours because of the risk of a biphasic reaction.
  • Offer the child/parents a referral to an allergy specialist (see www.bsaci.org for registered allergy clinics)
  • Offer the child/parents an adrenaline injector in the interim period whilst waiting for a specialist appointment

 

  • Before discharge, offer the child/parents
    • Information about anaphylaxis (signs, symptoms, risk of recurrence of symptoms (biphasic reaction)).  Parent information leaflet here.
    • Information about what to do if a reaction occurs (use adrenaline injector, call emergency services)
    • Demonstration on how to use an adrenaline injector see http://www.youtube.com/watch?v=pgvnt8YA7r8 for a clear American description of how to use it.
    • Advice about how to avoid potential triggers
    • Information about the need for referral and the referral process to an allergy specialist
    • Information about patient support groups

 

Research Recommendations

  • Mast cell tryptase is not always elevated in children, particularly if food is thought to be the allergen or if respiratory compromise is the main clinical feature. It is recommended that further studies be carried out to identify other potential chemical inflammatory mediators.
  • There is limited evidence on biphasic reactions. Follow up studies are recommended.
  • There are no studies on length of observation period following emergency treatment for suspected anaphylaxis
  • There is limited data on the annual incidence or anaphylactic reactions and their associated outcomes.
  • The Guideline Development Group feel that referral to specialist services and/or the provision of adrenaline injectors are likely to benefit patients who have experienced a suspected anaphylaxis as a result of decreased anxiety and ongoing support. This benefit is yet to be quantified.

December 2011. Happy Christmas!

December 2011 has snippets of information on torticollis (backed up with lots more information on the website), unconscious children, alkaline phosphatase and a link to the Map of Medicine’s recent algorithm for cough in children.  Also some pointers for your safeguarding training needs.  Download it here.

Limping child guideline

Limping Child Guideline

(with thanks to Dr Rajashree Ravindran)

Children who have hip pathology may present with a variety of non-specific symptoms. They may present with pain, refusal to bear weight, limp, or decreased movement of the lower extremity. If pain is present it is important to determine where it is coming from, as pelvis and low back pathology may refer pain to the hip region and hip pathology commonly presents with referred thigh or knee pain.[1]

The history should include

  1. pain characteristics
  2. trauma (recent/remote)
  3. mechanical symptoms (catching, clicking, snapping, worse during or after activity)
  4. systemic symptoms (fever, irritability, weight loss, anorexia)
  5. inflammatory symptoms (morning stiffness)
  6. neurological symptoms (weakness, altered sensation)
  7. gait (limp or not weight bearing)
  8. effects of previous treatments (including antibiotics, analgesics, anti-inflammatory drugs, physiotherapy)
  9. The current level of function of the child and development

 

Examination:

  1. Temperature and vital signs.
  2. Musculoskeletal exam including gait assessment: Look, Feel, Move approach to joint examination can be used. It should be noted that it is exceptionally rare to appreciate swelling of the hip on physical exam as it is a deep joint.
  3. A CNS examination is also vital to exclude any neurological pathology.
  4. Look for abdominal masses(Neoplasias in children can present with a simple limp)
  5. Examine the genitalia(testicular torsion may present simply as a limp[2]) and perform an ENT examination
  6. Look for rashes, bruises in unusual areas and remember the possibility of a non accidental injury.

 

Common differential diagnosis of limp by age:[2] 

0-3 years 3-10years 10-15 years
Septic arthritis or OsteomyelitisDevelopmental dysplasia of hip(usually does not present with pain)Fracture or soft tissue injury (toddler fractures or non accidental injury) Transient synovitis (Irritable hip)Septic arthritis or osteomyelitisPerthes’ diseaseFracture or soft tissue injury Slipped Upper Femoral epiphyses(SUFE)Septic arthritis or OsteomyelitisPerthes’ diseaseFracture or soft tissue injury

 

Also consider: Neoplasms, Neurological/ neuromuscular causes, Rheumatological disease such as Juvenile idiopathic arthritis

 

Investigations:

Limp due to trauma: If a traumatic fracture is suspected perform an x ray of the affected site and involve the orthopaedic team as appropriate. Always consider the possibility of non accidental injury in a younger child presenting with fracture.

Atraumatic limp: The algorithm as below can be used for guidance.  You may wish to give the parent information leaflet out as part of your “safety netting” as it reminds the family to seek further help if the limp is still present 1 or 2 weeks later.

Algorithm for Child presenting with an atraumatic limp

Parent information leaflet

REFERENCES

1.            Frick, S.L., Evaluation of the child who has hip pain. Orthop Clin North Am, 2006. 37(2): p. 133-40, v.

2.            Perry, D.C. and C. Bruce, Evaluating the child who presents with an acute limp. BMJ, 2010. 341: p. c4250.

3.            Kocher, M.S., D. Zurakowski, and J.R. Kasser, Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. J Bone Joint Surg Am, 1999. 81(12): p. 1662-70.

4.            Caird, M.S., et al., Factors distinguishing septic arthritis from transient synovitis of the hip in children. A prospective study. J Bone Joint Surg Am, 2006. 88(6): p. 1251-7.

5.            Howard, A. and M. Wilson, Septic arthritis in children. BMJ, 2010. 341: p. c4407.

6.            Kang, S.N., et al., The management of septic arthritis in children: systematic review of the English language literature. J Bone Joint Surg Br, 2009. 91(9): p. 1127-33.

7.            Kocher, M.S., et al., Validation of a clinical prediction rule for the differentiation between septic arthritis and transient synovitis of the hip in children. J Bone Joint Surg Am, 2004. 86-A(8): p. 1629-35.

8.            Padman, M. and B.W. Scott, (i) Irritable hip and septic arthritis of the hip. 2009. 23(3): p. 153-157.

January GP edition here!

January reminds us all of the NICE guideline on head injury and specifically when a child is supposed to be referred for a CT.  We continue our 6-8 week baby check series with information on undescended testes.  There are also links to agreed blood test reference ranges and resources to help with the identification of asthma inhalers.  Download January 2011 GP PDF here.

Blood test reference ranges

Click here for our agreed blood test reference ranges for children.  Ranges may vary from laboratory to laboratory so please check with your own service if you are unsure.  These ranges have been discussed with Whipps Cross Hospital and formally agreed by the paediatric Clinical Improvement Group at the hospital.

My colleague with an interest in haematology asked me to mention, as an addendum to the blood reference ranges, that the lower limit of normal of neutrophils for afrocaribbean children is 1.0 as long as all other parameters are OK.