Autosensitization (Id reaction and disseminated eczema)

Question 1

What is an Id reaction? And what are the common causes?

Answer 1

• secondary eczematous lesions developing in sites distant from primary exposure site
• usually allergic contact dermatitis +/- stasis dermatitis)

Question 2

What % of patients contact dermatitis and Stasis dermatitis will develop Id reaction?

Answer 2

• > 60%!!

Question 3

How long after initial lesions do Id reactions occur?

Answer 3

• can appear days to weeks after primary lesion

Question 4

Pathogenesis of Id reaction?

Answer 4

• unknown, but possibly:
• Hematogenous dissemination of allergens
• circulating activated memory T-cells

Question 5

Treatment of Id reaction?

Answer 5

• Topical steroids
• systemic antihistamines
• treat underlying cause