Question

24-year-old female presents with an itchy rash on the face, arms, and hands for 2 days after working in the garden, urticarial and vesicular lesions over the face, upper extremities, and hands. What is the most likely pathological process of this patient's rash?

A) Type I hypersensitivity reaction
B) Type II hypersensitivity reaction
C) Type III hypersensitivity reaction
D) Type IV hypersensitivity reaction

Answer 1

The rash described as itchy, urticarial, and vesicular is most likely caused by a Type IV hypersensitivity reaction, or delayed hypersensitivity, due to contact with an allergen like poison ivy.

Step-by-step explanation:

The most likely pathological process for the patient's rash described as itchy, urticarial and vesicular that developed after working in the garden is D) Type IV hypersensitivity reaction. This type of reaction, also known as delayed hypersensitivity, is a cell-mediated immune response initiated by sensitized T cells. It takes approximately one to two days after secondary exposure for a maximal reaction. Contact with plants like poison ivy typically triggers such reaction, and it manifests as inflammatory cytokines stimulating macrophages and cytotoxic T cells that elicit contact dermatitis.