Patch Testing — SCE Dermatology MCQ

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ModerateInflammatory DermatosesPatch TestingSCE Dermatology

A 35-year-old woman has had patch testing. Her dermatologist explains the concept of 'angry back' (excited skin syndrome). What is this?

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Correct answer: E — False positive patch test reactions caused by a state of generalised skin hyperreactivity when one or more strong true reactions are present

'Angry back' or excited skin syndrome occurs when one or more strongly positive patch test reactions create a state of generalised cutaneous hyperreactivity, causing adjacent or distant test sites to show false positive reactions. The mechanism involves cytokine spillover and non-specific inflammatory recruitment. It is suspected when multiple unexpected positive reactions occur alongside one or more very strong (++/+++) reactions. Management: retest the questionable allergens individually (serial testing) at a later date when the strongly reactive allergen is excluded from the test panel. This avoids false diagnoses of multiple contact allergies and unnecessary avoidance measures.

Reference: BAD 2017 Contact Dermatitis Guidelines; ICDRG