Allergic Conditions

Question 1

How do the antihistamines work?

Answer 1

Binds to H1 receptor site to block the action of histamine

Question 2

What are the sedating antihistamines?

Answer 2

Promethazine
Chlorphenamine
Hydroxyzine (QT prolongation)
Ketotifen

Question 3

What are the non-sedating antihistamines?

Answer 3

Acrivastine
Cetirizine
Loratadine
Fexofenadine

Question 4

What are antihistamines used for?

Answer 4

Nasal - hayfever
Skin - urticaria
Nausea and vomiting
Insomnia
Adjunct in emergency anaphylaxis and angioedema

Question 5

What antihistamines are used for nausea and vomiting?

Answer 5

Cinnarizine
Cyclizine
Promethazine hydrochloride
Promethazine teoclate 
Buclizine (migraines only OTC)

Question 6

What are the antihistamines used for insomnia?

Answer 6

Promethazine hydrochloride

Diphenhydramine

Question 7

What are the side effects of the antihistamines?

Answer 7

Old - more sedating + antimuscarinic

New - less sedation + less psychomotor impairment

Avoid alcohol

Driving may be impaired

Question 8

What are the cautions with antihistamines?

Answer 8

BPH
Glaucoma
Severe liver impairment

Dementia with sleeping tablets - can affect memory

Question 9

What is the MHRA for hydroxyzine?

Answer 9

QT prolongation + torsades de pointes

Question 10

Is hydroxyzine used for a short period or long period?

Answer 10

Short

Max dose 100mg

Question 11

What are the contraindications for hydroxyzine?

Answer 11

Drugs that prolong QT interval 
CVD
Family history of sudden death
Hypokalaemia
Hypomagnesaemia 
Bradycardia

Question 12

What are the uses for allergen immunotherapy?

Answer 12

Reduce allergic asthma symptoms
Allergic rhinoconjunctivitis
Reduce severe anaphylaxis in hypersensitivity to wasp and bee stings

Question 13

What are the desensitising vaccines used for?

Answer 13

Hay fever unresponsive to other anti allergy drugs

Hypersensitivity to wasp and bee venom

Question 14

Who do the allergen vaccines need to be avoided in?

Answer 14

Asthma
Pregnant women
Children under 5 years
Beta blockers
ACEi

Question 15

What is the omalizumab injection used for?

Answer 15

As an add on treatment for

Severe persistent allergic asthma 6+

Chronic spontaneous urticaria 12+

Question 16

What are the side effects of the omalizumab injection?

Answer 16

Churg Strauss syndrome and hypersensitivity reactions

Question 17

How do you treat anaphylaxis?

Answer 17

Secure airways and restore blood pressure
Raise legs and lay flat
If sick or unconscious place in recovery position

Adrenaline 
Repeat every 5 mins if necessary 
< 6 - 150mcg
6-12 - 300 mcg
12+ - 500 mcg

Question 18

Can adrenaline be given to patients on beta blockers?

Answer 18

Yes but IV salbutamol may be better

Question 19

What are the adjuncts used in anaphylaxis?

Answer 19

High flow oxygen and IV fluids
Chlorphenamine injection
Hydrocortisone injection

Question 20

What is the MHRA advice for auto injectors?

Answer 20

Prescribe 2 auto injectors. Carry at all times

Patient/carer trained on how to use

Check expiry dates

Question 21

What is angioedema?

Answer 21

Swelling of the skin often caused by allergic reactions

Question 22

How do you treat laryngeal oedema?

Answer 22

Adrenaline
Antihistamine
Corticosteroid