Urticaria (acute and chronic)

Question 1

Definition

Answer 1

Itchy, red, blotchy rash resulting from swelling of the superficial part of the skin. Angiooedema occurs when the deep tissues, the lower dermis and subcutaneous tissues are involved and become swollen.

AKA hives

Question 2

Aetiology

Answer 2

· Caused by activation of mast cells in the skin, resulting in the release of histamines

· The cytokine release leads to capillary leakage, which causes swelling of the skin and vasodilation –> erythematous appearance

Question 3

Possible triggers

Answer 3

o ACUTE urticaria

· Allergies (foods, bites, stings)
· Viral infections
· Skin contact with chemicals
· Physical stimuli

o CHRONIC urticaria

· Chronic spontaneous urticaria - medication, stress, infections
· Autoimmune`

Question 4

Epidemiology

Answer 4

· 15% of general population experience urticaria at some point in life

· Acute is much more common than chronic urticaria

Question 5

Presenting symptoms

Answer 5

· Central itchy white papule or plaque surrounded by erythematous flare

· Lesions vary in size and shape

· May be associated with swelling of the soft-tissues of the eyelids, lips and tongue (angiooedema)

· Individual lesions are usually transient

Question 6

Timescales of presenting symptoms

Answer 6

o Acute - symptoms develop quickly but normally resolve within 48 hrs

o Chronic - rash persists for > 6 weeks

Question 7

Investigations

Answer 7

· Usually clinical

· Tests may be required for chronic urticaria (e.g. FBC, ESR/CRP, patch testing, IgE tests)