Paediatric Infection and Immunity - Allergies, Conjunctivitis, Impetigo and Chickenpox

Question 1

What is an allergy?

Answer 1

Immunological hypersensitivity leading to a variety of disease

May or may not be IgE mediated

Question 2

What is an allergen?

Answer 2

Substance that stimulates the production of IgE or cellular immune response

Question 3

What is sensitisation?

Answer 3

Production of IgE antibodies after repeated allergen exposure

Asymptomatic

Question 4

What is required for something to be an allergy?

Answer 4

Symptoms + specific IgE rise

Question 5

Give examples of atopic disease

Answer 5

Allergic rhinitis
Allergic conjunctivitis
Asthma
Atopic dermatitis (Eczema)
Urticaria
Insect, food and drug allergy

Question 6

How does urticaria present and when is it not allergic?

Answer 6

Maculo-papular pruritic rash

If chronic >6weeks, not allergic

Question 7

What are the hypotheses for increasing allergies?

Answer 7

Hygiene hypothesis
Dual allergen hypothesis
Vitamin D hypothesis

Question 8

What is the hygiene hypothesis?

Answer 8

Microbiological exposure low in developed environment so immune system development is suppressed

Question 9

What is the dual allergen hypothesis?

Answer 9

Exposure through skin may lead to allergy

However, consumption will lead to tolerance

Question 10

What is the vitamin D hypothesis?

Answer 10

Need high levels of Vit D to regulate the immune system

Question 11

What can you do to reduce risk of allergy onset?

Answer 11

Good skin hygiene
Microbial exposure - pets
Vitamin D
Early weaning - varied diet

Question 12

What are the types of allergic rhinitis?

Answer 12

Seasonal - hayfever
Persistent - dust mites, pets
Occupational - flour, wood dust

Question 13

What is the pathophysiology of allergic rhinitis?

Answer 13

IgE mediated inflammation of the nasal mucosa

Mast cells release histamines - increase epithelial permeability

Inflammatory cell migration

Acute and late phase response

Question 14

What happens in the acute phase response?

Answer 14

Sneezing followed by secretions

Question 15

What happens in the late phase response?

Answer 15

6-12 hours after –> nasal congestion

Question 16

What symptoms does allergic rhinitis present with?

Answer 16

Bilateral nasal congestion
Itching
Sneezing
Discharge
Watery, red eyes

Question 17

How is allergic rhinitis assessed?

Answer 17

Diagnosis from history

Can do skin prick or IgE testing via ELISA

Question 18

How is allergic rhinitis managed?

Answer 18

Avoid allergen
Cetirizine
>5yo - try topical nasal antihistamines PRN

Nasal steroids if nasal blockage predominant symptom

Question 19

How can food allergies be split up?

Answer 19

Immunological - IgE mediated and Non-IgE mediated

Non-immunological

Question 20

What symptoms would all immunological food allergies present with?

Answer 20

Pruritis
Diarrhoea
Abdo pain

Question 21

What symptoms of food allergy would be indicative it is IgE mediated?

Answer 21

Urticaria
Angio-oedema
Oral itching
Sneezing
SOB and wheeze
Signs of anaphylaxis

Question 22

What symptoms of a food allergy would indicate it is a non IgE mediated immunological allergy?

Answer 22

Eczema
GORD and colic
Bowel changes
Poor growth

Question 23

What symptoms would indicate a food allergy is non immunological?

Answer 23

Take hours - days to occur
Headache
Fatigue
Bowel changes
Urticaria

Question 24

How are IgE mediated food allergies investigated?

Answer 24

Food diary
Physician supervised oral food challenge
Skin prick
Allergen specific IgE measurements via ELISA

Question 25

How is a non IgE mediated food allergy investigated?

Answer 25

Trial elimination diet

Question 26

How are immunological food allergies managed?

Answer 26

Food avoid Dietician referral Antihistamines Adrenaline

Question 27

How are non-immunological food allergies managed?

Answer 27

Food avoidance | Dietician referral

Question 28

What commonly causes lactose intolerance?

Answer 28

Post-viral gastroenteritis lactase deficiency

Question 29

What is the pathophysiology of lactose intolerance?

Answer 29

Lactase normally decrease with age If accelerated - lactose intolerance Lactose pass into colon and fermented - diarrhoea and bloating

Question 30

How can cows milk protein allergy present?

Answer 30

``` With other food allergies Colic Oesophagitis Constipation Acute colitis ```

Question 31

How are infants with cows milk protein allergy fed?

Answer 31

Hydrolysed formula first Then wean onto cows milk protein free diet

Question 32

What organisms commonly cause conjunctivitis?

Answer 32

Adenovirus Staph Strep pneumoniae H Influenzae

Question 33

How does conjunctivitis present?

Answer 33

Generalised red eye Irritated gritty feeling Vary depending on bacterial or viral History of close contact

Question 34

What symptoms are indicative of bacterial conjunctivitis?

Answer 34

Purulent discharge | Eyes stick together

Question 35

What symptoms are indicative of viral conjunctivitis?

Answer 35

Serous discharge Recent URTI Periauricular lymphadenopathy

Question 36

How is viral conjunctivitis managed?

Answer 36

Self limiting - resolve in 2 weeks Lubricant eye drops, warm water No school exclusion but don't share towels etc.

Question 37

How is bacterial conjunctivitis treated?

Answer 37

Antibiotics if severe - Chloramphenicol Prescribing can be delated - 3 days with no improvement

Question 38

What is impetigo?

Answer 38

Superficial skin infection by staph aureus or strep pyogenes

Question 39

What are risk factors for impetigo?

Answer 39

Poor hygiene | Break in skin - eczema, bites

Question 40

How does impetigo present?

Answer 40

``` Usually around a month Tiny vesicles which crust into honey coloured plaques Rapidly spreading Some itching No erythema or oedema Regional lymphadenopathy ```

Question 41

How is impetigo investigated?

Answer 41

Swab for culture if lesion widespread or MRSA suspected

Question 42

How is impetigo managed?

Answer 42

``` Keep area clean - soap and water Avoid sharing towels, dummies etc No school until lesions crusted or antibiotics for 48hrs Fusidic acid - topical Oral fluclox if widespread or bullous ```

Question 43

What are the complications associated with impetigo?

Answer 43

Cellulitis | Staph scaled skin syndrome

Question 44

What is bullous impetigo?

Answer 44

Thin roofed lesions which rupture seen on top of other lesions

Question 45

Where is bullous impetigo most commonly seen?

Answer 45

Face, trunk and buttocks

Question 46

Who is bullous impetigo most commonly seen in?

Answer 46

Neonates

Question 47

What organism causes chicken pox?

Answer 47

Varicella zoster

Question 48

What is a key property of chicken pox?

Answer 48

Infectious!

Question 49

How and when does chicken pox spread?

Answer 49

Via respiratory route from someone who has chicken pox or shingles 4 days before rash --> 5 days after rash appear

Question 50

How long is the incubation period for varicella zoster?

Answer 50

10-21 days

Question 51

How do children with chicken pox present?

Answer 51

38-39 degrees for up to 4 days | Itchy rash on head and trunk

Question 52

What is the progression of the chicken pox rash?

Answer 52

Macular --> papular --> vesicular --> crust

Question 53

What complications are associated with chicken pox?

Answer 53

Bacterial infections of lesion Pneumonia Encephalitis

Question 54

How is chicken pox managed non pharmacologically?

Answer 54

Calamine lotion Trim nails Exclude from school - 5 days after rash onset

Question 55

How is chicken pox managed pharmacologically?

Answer 55

Varicella zoster immunoglobulin for immunocompromised and newborns exposed to it Aciclovir if contract chicken pox

Question 56

What can be seen on chest X-ray with varicella pneumonia?

Answer 56

Miliary opacities

Question 57

What are each of the HHV's and what disease do they cause?

Answer 57

HHV1 - herpes simplex 1 - oral infection and encephalitis HHV2 - herpes simplex 2 - neonatal and genital infection HHV3 - varicella zoster - chickenpox and shingles HHV4 - Epstein Barr virus - glandular fever HHV5 - Cytomegalovirus - congenital & immunocompromised HHV6/7 - Roseola