Allergic conditions

Question 1

what conditions can oral antihistamines be of value in? (6)

Answer 1

1) Nasal allergies- reduce rhinorrhoea and sneezing
↳Less effective for nasal congestion
2) Preventing urticaria, Pruritus
3) Drug allergies
4) Insect bites and stings
5) Insomnia (promethazine)
6) Nausea and vomiting

Question 2

which two antihistamines can be used as an adjunct to adrenaline/epinephrine in the emergency treatment of anaphylaxis and angioedema?

Answer 2

Injections of chlorphenamine or promethazine HCL

Question 3

1) which antihistamines can be used in nausea and vomiting? (3)
2) Which antihistamine is included as an anti-emetic in preparations for migraines?

Answer 3

1) Cinnarizine, Cyclizine, Promethazine teoclate

2) Buclizine (found in migraleve)

Question 4

What can the sedating activity of some older antihistamines be used to manage?

Answer 4

sometimes used to manage the pruritus associated with some allergies

Question 5

1) List some non-sedating antihistamines (5)

↳ Explain why these drugs cause less sedation

Answer 5

1) Acrivastine
2) Cetirizine
3) Loratadine
4) Fexofenadine
5) Mizolastine
↳ Penetrate the BBB to a lesser extent so cause less sedation and psychomotor impairment than the older antihistamines

Question 6

1) What conditions can be treated with allergen vaccines (immunotherapy)?
2) What do these vaccines contain?

Answer 6

1) Can reduce symptoms of asthma and allergic rhinoconjunctivitis.
↳ vaccines containing bee and wasp venom can reduce the risk of severe anaphylaxis in those who are allergic
2) Contain house dust mite, animal dander or extracts of grass and tree pollen

Question 7

Omalizumab is a monoclonal antibody that binds to immunoglobulin E (IgE). What condition is it licensed to treat under a specialist?

Answer 7

Add-on therapy in IgE-mediated sensitivity to inhaled allergens, where severe persistent allergic asthma cannot be controlled adequately with high dose ICS + LABA

Question 8

Anaphylaxis is a severe, life-threatening, generalised or systemic hypersensitivity reaction. What symptoms are characteristic of an anaphylaxis reaction? (3)

Answer 8

1) Rapid onset of respiratory and/or circulatory problems
2) Associated with skin and mucosal changes
3) Swelling of the lips, tongue or throat

Question 9

Which group of patients are at particular risk of life-threatening reactions?

Answer 9

Patients with pre-existing asthma, especially poorly controlled asthma

Question 10

List some medicinal products particularly associated with anaphylaxis reactions (5)

Answer 10

1) Blood products
2) Vaccines
3) Antibacterials
4) Aspirin and other NSAIDs
5) Neuromuscular blocking drugs

Question 11

Outline the first-line treatment for anaphylaxis (5)

Answer 11

1) Secure airway, restore BP (laying flat and raising legs or recovery position)
2) IM Adrenaline: repeated if necessary at 5-minute intervals. Patients on B-blockers require special consideration
3) High-flow oxygen and IV fluids
4) Antihistamine (e.g. chlorphenamine), by slow IV/IM injection = useful adjunctive treatment after adrenaline
5) IV corticosteroid (e.g. hydrocortisone) = of secondary value

Question 12

When might adrenaline be given as a dilute solution via the intravenous route?

Answer 12

When a patient is so ill that there is doubt about the adequacy of the circulation
↳ (IV route is also used for cardiac resuscitation)

Question 13

What should be given to patients with continuing respiratory deterioration?

Answer 13

Further treatment with bronchodilators:
Salbutamol - IV/inhaled
Ipratropium bromide - IV/inhaled
Aminophylline - IV
\+ Oxygen

Question 14

Why is IV hydrocortisone of secondary value in the initial management of anaphylaxis?

Answer 14

Onset of action is delayed for several hours, but should be given to prevent further deterioration in severely affected patients

Question 15

What further treatment might be considered in patients who are discharged from hospital, following an anaphylaxis reaction?

Answer 15

Oral antihistamine and an oral corticosteroid for up to 3 days to reduce the risk of further reactions

Question 16

How should patients who are suspected to have had an anaphylactic reaction be managed?

Answer 16

1) Referred to a specialist for specific allergy diagnosis

2) Auto-injector should be given for self-administration

Question 17

1) Why is the intramuscular route the first choice route for the administration of adrenaline in anaphylaxis?
2) Where exactly should the IM injection be administered?

Answer 17

1) Rapid onset of action after IM administration and in the shocked patient its absorption is faster and more reliable than from a subcutaneous site
2) Anterolateral aspect of the middle third of the thigh

Question 18

What is angioedema?

Answer 18

Swelling of the deeper layers of the skin, caused by a build-up of fluid. Can affect any part of the body, but swelling usually affects the: Eyes lips, hands, feet

Question 19

Angioedema is dangerous if laryngeal oedema is also present. If this was the case, how would it be managed?

Answer 19

1) Adrenaline and oxygen the same as in Anaphylaxis
2) Antihistamines and corticosteroids
3) Tracheal intubation may be necessary

Question 20

The treatment of hereditary angioedema is different to that of allergic angioedema and adrenaline, oxygen, antihistamines and cotricosteroids should not be used as they are ineffective . Outline the treatment of hereditary angiodema

Answer 20

1) C1-esterase inhibitor, derived from human plasma,can terminate acute attacks
2) Conestat alfa and icatibant are licensed for the treatment of acute attacks in those with C1-esterase inhibitor deficiency

Question 21

which 2 drugs are used for short-term and long-term prophylaxis of hereditary angioedema?

Answer 21

Tranexamic acid or danazol
↳ when used short term its started several days before planned procedures and continued for 2–5 days
afterwards

Question 22

What dose of intramuscular adrenaline should be prescribed in the following people for anaphylaxis:

1) Child 1 month -5 years
2) 6-11 years
3) Child 12-17 years
4) Adult

Answer 22

1) Child 1 month -5 years: 150 micrograms
2) 6-11 years: 300 micrograms
3) Child 12-17 years: 500 micrograms
4) Adult: 500 micrograms
↳ doses for all can be repeated after 5 minutes if needed according to BP, pulse and respiratory function
↳ in general body weight up to 15kg give 150mcg, if above 30kg give 300mcg+