Urticaria (Hives)

Question 1

What is urticaria?

Answer 1

Central itchy what papule or plaque due to dermal oedema (weal), also known as hives. An erythematous flare surrounds it. The shape and size varies and may be associated with soft tissue like eyelids, lips and tongue (angio-oedema).

Question 2

What is the epidemiology of urticaria?

Answer 2

• 15% of people will have experienced urticaria at least once in their lives
• Prevalence rate of 1-5/1000
• Most common age for chronic urticaria is the 4th and 5th decades

Question 3

What are the causes of urticaria?

Answer 3

• Immune-the release of histamine and other mediators from mast cells
• Idiopathic
• Hereditary- c1 esterase inhibitor deficiency

Question 4

What are the risk factors for urticaria?

Answer 4

• Stress
• Exercise
• Helminth infection
• SLE
• Temperature
• Drugs
• Sun exposure
• Scratching

Question 5

What are the symptoms of urticaria?

Answer 5

• Central itchy papule or plaque with erythematous flar

- Lesions come and go within a few hours

Question 6

What are the signs of urticaria?

Answer 6

• Diagnosis established once it has been shown that individual lesions only last a few hours
• Weals of urticaria look pink-red and can be different shapes and sizes. They usually look like nettle stings

-rash normally lasts for 6 to 12 months

Question 7

What are the differential diagnosis of urticaria?

Answer 7

Pemphigoid

Eczema

Question 8

What are the investigations for urticaria?

Answer 8

Rarely needed but if needed:

• FBC, ESR, thyroid antibodies
• Check if the patient is dermographic by stroking the skin with a spatula

Question 9

What are the treatments for urticaria?

Answer 9

• Non-sedating H1 antihistamines, e.g. Acrivastine, Cetirizine hydrochloride, fexanidine hydrochloride
• -Sedating antihistamines can be used if pruritis is causing sleep disturbances