Urticaria

Question 1

Define urticaria

Answer 1

Superficial swelling of the skin (epidermis and mucous membranes) that result in a red (initially with a pale centre), raised, and intensely itchy rash

Question 2

What is the difference between acute and chronic urticaria

Answer 2

Acute urticaria = symptoms < 6 weeks
Chronic urticaria = symptoms > 6 weeks

Question 3

What are the causes of acute urticaria

Answer 3

Spontaneous, idiopathic
Acute viral infection
Allergic reaction: foods, insect bites, contact allergens, drugs (penicillin, aspirin, NSAIDs, vaccinations)

Question 4

What are the causes of chronic urticaria

Answer 4

Chronic spontaneous urticaria (CSU)
Autoimmune urticaria
Chronic inducible: aquagenic, cholinergic, cold, heat, symptomatic dermatographism, delayed pressure, solar, contact
IgE mediated reaction
Viral infection

Question 5

What is the pathophysiology of urticaria

Answer 5

Skin mast cell activation → release of histamine, leukotrienes, prostaglandins → Local vasodilation and increased permeability of capillaries and venules
Urticaria of deeper tissues → angioedema

Question 6

What are the risk factors for urticaria

Answer 6

Family history
Co-existing allergy or atopy

Question 7

What is the epidemiology of urticaria

Answer 7

Females > males
Acute is more common in children and adolescents that in adults, whereas chronic is more common in adults
Affects 3% of children

Question 8

What are the symptoms of urticaria

Answer 8

Hives
Itchy
Arise shortly after exposure to the potential allergen (<1 hour)
Reproducible
(1) A central swelling of variable size (red or white in colour), almost invariably surrounded by an area of redness (flare).
(2) Associated itching or burning)
(3) Skin returns to normal within 1-24 hours
Redness to skin

Question 9

What are the differentials for urticaria

Answer 9

Atopic eczema
Contact dermatitis
Chronic pruritus
Erythema multiforme
Insect bite or sting
Polymorphic eruption of pregnancy

Question 10

What are the signs of urticaria on examination

Answer 10

Urticaria
- Weals that vary in size (mm to hand-sized)
- Single or numerous, localised or generalised
- A central swelling of variable size (red or white in colour), almost invariably surrounded by an area of redness (flare)

Question 11

investigations for urticaria

Answer 11

Clinical diagnosis, investigations done if there is no obvious cause

Bloods: TFTs, CRP/ESR, FBC
Other: skin prick testing, skin biopsy

Question 12

What is the management for urticaria

Answer 12

1. Assess severity - Urticaria Activity Score (UAS7)
   Records severity of itching + no. of weals for 7 days
   <7 in 1 week = control
   >28 in 1 week = severe disease
2. Identify any potential triggers e.g. with symptom diary
3. arrange investigations if trigger cannot be found

Question 13

What is the management for mild urticaria

Answer 13

Supportive - Likely to be self-limiting without treatment

Question 14

What is the management for moderate urticaria

Answer 14

First line: Non-sedating anti-histamines (second gen) - Cetirizine for up to 6 weeks
Second line: oral corticosteroid e.g. prednisolone

+ follow up

Question 15

What is the management for severe urticaria

Answer 15

Non-sedating anti-histamines (second gen) - Cetirizine for up to 6 weeks + oral corticosteroid e.g. prednisolone
Contact dermatology
Refractory: omalizumab (anti-IgE antibody)

+ follow up
+ consider psychology referral

Question 16

What are the complications of urticaria

Answer 16

Progression to angioedema and anaphylaxis, Airway obstruction
Skin infection — due to extensive itching and subsequent excoriation.
Scarring — uncontrolled excoriation can lead to scarring.
Poor sleep — due to itching.
Social isolation and embarrassment.
Reduced performance at work or school.
Anxiety and depression.
Reduced quality of life

Question 17

What is the prognosis for urticaria

Answer 17

Excellent prognosis, normally self-limiting and short-lived
Most react well to the allocated treatment
50% of people with CSU go into remission after 6 months-5 years

Question 18

What are the complications of oral corticosteroid use

Answer 18

Growth retardation
Diabetes mellitus
HTN
Osteoporosis