Dermatology/ Urticaria

Question 1

How do urticarial lesions(hives) typically present?

Answer 1

• Pruritic, raised, erythematous plaques with or without central pallor that can enlarge and coalesce

Question 2

What is the hallmark of urticarial lesions as opposed to other red skin rashes?

Answer 2

Lesions disappear within a few hours after onset without leaving any residual marks

Question 3

What is the time-course of acute urticaria and chronic urticaria?

Answer 3

• Acute urticaria resolves within several hours without residual marks.
• Chronic urticaria comes and goes, but is present on most days and lasts for more than 6 weeks.

Question 4

What are the two classes of antibiotics most frequently implicated in antibiotic-induced urticaria?

Answer 4

1. Beta-lactams
2. Sulfa-containing antibiotics (eg, bactrim)

Question 5

Generalized urticaria following an insect sting should raise concern for what type of potentially life-threatening reaction with a future sting?

Answer 5

Anaphylaxis

Question 6

How should patients with generalised urticaria after and insect stin be managed?

Answer 6

Inform the patient about this risk, and ensure that they have epinephrine with them at all times.

Question 7

What is the treatment of urticaria?

Answer 7

Remove the offending agent and use antihistamine H1-receptor blockers as first line, with H2-receptor blockers as adjunctive therapy; short-term course of systemic steroids can be used for patients who fail antihistamine therapy.

Question 8

What are the characteristic features of urticarial vasculitis?

Answer 8

Painful rather than pruritic wheals that persist beyond 24 hours and leave a residual pigmentation

Question 9

Name four systemic diseases in which urticaria can be a presenting sign.

Answer 9

1. Urticarial vasculitis
2. Systemic lupus erythematosus
3. Autoimmune thyroid disease
4. Cryoglobulinemia

Question 10

How is angioedema different from urticaria?

Answer 10

Angioedema is deeper in the dermis and subcutaneous tissues resulting in more extensive swelling and edema

Question 11

Describe four types of physical urticarias.

Answer 11

1. Immediate pressure—presents as dermatographism, often at sites of constricting undergarments
2. Delayed pressure—often affects the hands and feet
3. Cold—wheals in response to cold temperatures
4. Cholinergic—punctuate, pencil-eraser-sized wheals as cholinergic response to exercise, sweating, and/or hot showers