Clinical Classification For Urticaria

Question 1

What is acute urticaria?

Answer 1

Last less than 6 weeks

Usually non-specific trigger commonly viral of nature through non-immune mechanisms

Question 2

What is chronic urticaria?

Answer 2

Persistent for longer than 6 weeks and usually a physical urticaria or a chronic autoimmune urticaria

Question 3

What is an episodic urticaria?

Answer 3

Last short periods intermittently but recurring over months or years.
Caused by recurrent episodic exposure to an allergic trigger.

Question 4

What causes urticaria

Answer 4

Mast cell degranulation

Question 5

How are mast cells degranulated

Answer 5

Immune system- allergic urticaria

Direct release- non-allergic urticaria

Question 6

How is allergic urticaria divided?

Answer 6

IgE-mediated

Non-IgE-mediated

Question 7

What composes the IgE-mediated urticaria

Answer 7

Local

Generalised- Acute IgE mediated

Question 8

What makes up the non-IgE mediated urticaria (5)

Answer 8

Direct mast cell destabilisation 
Drugs
Viral infection
Exogenous histamine
Physical stimuli

Question 9

What causes direct mast cell destabilisation

Answer 9

Strawberries

Shellfish

Question 10

What drugs cause non-IgE mediated allergic reaction?

Answer 10

Opiate
Radiocontrast
Vancomycin - red men syndrome

Question 11

What is the most common cause for acute urticaria

Answer 11

Viral infection

They last longer than other causes of acute urticaria

Question 12

What is possible source from exogenous histamine

Answer 12

Scombroid fish poisoning as the dark meat contain histadine which than becomes histamine when spoiled

Question 13

How does Scombroid fish poisoning present

Answer 13

Flushing
Urticaria 
Vomiting 
Diarrhoea 
This a toxic adverse reaction

Question 14

Name the different physical urticaria (7)

Answer 14

Dermatographism
Cold urticaria 
Cholinergic urticaria 
Delayed pressure urticaria 
Solar urticaria 
Aquagenic urticaria 
Vibration urticaria

Question 15

What is the most common physical urticaria?

Answer 15

Dermatographism

Question 16

What causes Dermatographism

Answer 16

Stroking or scratching the skin with light- moderate touch/pressure

Question 17

How is Dermatographism diagnosed

Answer 17

By eliciting and demonstrating it

Question 18

What causes cold urticaria

Answer 18

Cold weather
Handling cold objects
Bathing in cold water

Question 19

What are the types of cold urticaria

Answer 19

Localised
Systemic which is dangerous as it can cause severe symptoms such as hypotension and collapse as well as drowning when immersed in cold water
Cold-induced Dermatographism

Question 20

How is cold urticaria diagnosed

Answer 20

Ice tube in thin plastic is placed on site for 5-10 minutes if there is urticaria when rewarming than you have cold urticaria

Question 21

What is cholinergic urticaria

Answer 21

Generalised heat-induced urticaria

Question 22

What causes cholinergic urticaria

Answer 22

Exercise 
Sweating
Hot showers 
Emotional stress
Fever

Question 23

Why is it named cholinergic not heat-induced urticaria

Answer 23

Because the sweat glands enervated with cholinergic nerve fibres are responsible for this

Question 24

How is cholinergic urticaria diagnosed

Answer 24

By sweating exercise (and 15minutes after sweating)

Passively heating body temperature

Question 25

What may cholinergic urticaria cause

Answer 25

Severe hypotension

Question 26

What is delayed pressure urticaria?

Answer 26

Swelling that occurs 2-6 hours after sustained pressure applied usually from tight clothes and sitting on buttocks

Question 27

Up to how long does delayed pressure urticaria last and what sensation does it have

Answer 27

24-48 hours and sometimes up to 72 hours

Also has burning kind of sensation

Question 28

How is delayed pressure urticaria diagnosed

Answer 28

Applying pressure locally for 10-20 minutes OR

wearing a rucksack with a 3cm strap containing 5-10kg for 15 minutes