Urticaria and Angioedema

Question 1

What is urticaria

Answer 1

A superficial swelling of the skin (epidermis and mucous membranes) that results in a blanching red (initially with a pale centre), raised, non-painful and intensely itchy rash. Typically lasts less than 24 hours and leaves no residual marks on resolution

Question 2

What is angioedema, how often does it copresent with urticaria

Answer 2

A deeper form of urticaria with transient swellings of deeper dermal, subcutaneous and submucosal tissue. This often affects the face (lips, togue and eyeids), hand and feet. Can coexist with urticaria in about 40% of cases

Question 3

How can urticaria be classified

Answer 3

According to duration:
* Acute urticaria- symptoms last for less than 6 weeks- causes include acute viral infections, allergic reactions to food, insect bites latex and drugs (commonly penecillin, aspirin, NSAIDs, vaccinations)
* Chronic urticaria- symptoms persist for 6 weeks or longer, on a nearly daily basis

According to cause:
* Chronic spontaneous urticaria- no known identifiable cause- can be aggravated by heat, stress, certain drugs and infections (e.g helicobacter)
* Autoimmune urticaria- characterised by the presence of IgG autoantibodies to the igE receptor- often associated with other autoimmune conditions
* Chronic inducible urticaria- includes aquagenic, heat, cold, solar, vibrational, contact urticaria

Question 4

Prevalence of urticaria in children

Answer 4

Affects around 3% of children and as a lifetime prevalence of approximately 20% (more common in atopy)

Question 5

Complications of chronic urticaria

Answer 5

Skin infection (due to excoriation), scarring, poor sleep, social isolation and embarressment, anxiety, poor school performance.
Angioedema can lead to airway obstruction

Question 6

Investigations for urticaria

Answer 6

• Consider using tools such as the Urticaria Activity Score (UAS7)- records the severity of itching and the number of wheals daily for 7 days (score of less than 7= good control, score of 28= severe disease
• Detailed history to identify tiggers- In IgE mediated allergy, symptoms typically are repoducible within 1 hour of exposure to offending factor

Question 7

Differentials for urticaria

Answer 7

Atopic eczema (lesions usually accompanied by a greater degree of erythema and dry skin, also typically lasts >24 hours), contact dermatitis (lesion tends to be more irritated and the rash tends to last >24 hours), chronic pruritis, insect bite or sting, urticarial vasculitis (typically painful, non-blanching, palpable, >24 hours)

Question 8

Management of urticaria

Answer 8

• Identify and avoid triggers and if possible give clear instruction on avoidance strategies (should have a trial without treatment if drug is causing urticaria)
• Keep a symptom diary to determine the frequency, duration, and severity of episodes
• Calculate the UAS7 score
• For people with mild urticaria with an identifiable and avoidable cause/ trigger: advise that the urticaria is likely to be self-limiting

For people with symptoms requiring treatment:
* Offer a non-sedating antihistamine (cetirizine, loratadine are usual choices in children)
* Usually given for up to 6 weeks, but can be given for 3-6 months if the symptoms will be persistent or recurrent (can also be prescribed as required)
* Should refer if severe for a single course of oral corticosteroid (prednisolone), since steroids can interfere with normal growth in children
* If there is no improvement following treatment, refer for specialist advice for consideration of step-up in medication. Also if: painful and persistent, acute severe urticaria due to food or latex allergy
* Provide information: Itchy Wheezy Sneezy, NHS- Urticaria, Allergy UK website

Question 9

Management of agioedema

Answer 9

For people with rapidly developing angio-oedema without anaphylaxis:
* Give chloramphenamine and hydrocortsone slowly as an IV infusion or IM
* Arrange emergency admission and review review post-dicharge (monitor for anaphylaxis)

For people with stable angio-oedema without anaphylaxis:
* Treatment may not be needed where symptoms are mild
* If treatment is required offer a non-sedating antihistamine (cetirizine, loratadine) for up to 6 weeks and consider a short course of prednisolone if symptoms are severe. Advise parents to seek immediate medical help if symptoms rapidly develop or if anaphylaxis develops

Treatment can be prescribed for 6-12 months if the child has a long history of urticaria and angioedema (should refer to a dermatologist or immunologist if hereditary, or cause is not identifiable/unavoidable)

Refer to Allergy UK, NHS website