Micro & Immunology · single question
A patient with a metal framework RPD returns with an allergic reaction. What type of hypersensitivity reaction is contact dermatitis?
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Correct answer: D. Type IV (delayed, cell-mediated)
✓ D) Type IV (delayed, cell-mediated) is correct.
Contact dermatitis (e.g., from nickel in metal alloys) is a classic Type IV hypersensitivity reaction — delayed-type, T-cell mediated, occurring 48–72 hours after exposure. There is NO antibody involvement. The appropriate management is to ask the lab what alloy was used, identify the offending metal (usually nickel), and replace with a biocompatible alternative (titanium, cobalt-chromium with low nickel). Type I = anaphylaxis/immediate allergic reaction.
Contact dermatitis (e.g., from nickel in metal alloys) is a classic Type IV hypersensitivity reaction — delayed-type, T-cell mediated, occurring 48–72 hours after exposure. There is NO antibody involvement. The appropriate management is to ask the lab what alloy was used, identify the offending metal (usually nickel), and replace with a biocompatible alternative (titanium, cobalt-chromium with low nickel). Type I = anaphylaxis/immediate allergic reaction.
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