A 32-year-old woman develops a pruritic, eczematous rash on her earlobes 48 hours after wearing new nickel earrings. Biopsy of the rash would show which of the following predominant cell types?
- A Eosinophils
- B Neutrophils
- C CD4+ T lymphocytes ✓
- D CD20+ B lymphocytes
Correct answer: C. CD4+ T lymphocytes
Explanation
Type IV hypersensitivity is a T-cell mediated reaction. The rash of contact dermatitis peaks at 48-72 hours and is characterized by perivascular infiltration of CD4+ T lymphocytes and macrophages. Neutrophils and eosinophils are more typical of Type III and Type I reactions, respectively. C lymphocytes are not the primary effector cells in this delayed-type response.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.