White Blood Cell Elevation After Bee Sting
Eosinophils (Option A) are the most likely white blood cell to be elevated after a bee sting, as this represents a Type I IgE-mediated hypersensitivity reaction with subsequent allergic inflammation.
Immunologic Mechanism of Bee Sting Reactions
The pathophysiology of bee sting reactions centers on IgE-mediated hypersensitivity, which characteristically involves eosinophil recruitment and activation 1, 2:
- Bee venom components trigger Th2-type T cell responses that release IL-4 and IL-13, directing B cells to produce venom-specific IgE 2
- IgE crosslinks FcεR1 receptors on mast cells and basophils, causing immediate degranulation with histamine and inflammatory mediator release 2
- The late-phase allergic response (24-72 hours post-sting) recruits eosinophils to the site, which is the hallmark of IgE-mediated allergic reactions 1, 2
Why Eosinophils Are Elevated
Eosinophils are the signature cell of allergic/atopic responses:
- Type I hypersensitivity reactions characteristically elevate eosinophils both locally at the sting site and systemically in the peripheral blood 2
- Large local reactions peaking at 48-72 hours represent IgE-mediated late-phase reactions with prominent eosinophilic infiltration 1
- Venom-specific IgE is detectable in the vast majority of patients experiencing systemic or large local reactions, confirming the allergic nature 1
Why Other Options Are Less Likely
Basophils (Option B):
- While basophils do participate in IgE-mediated reactions and degranulate alongside mast cells, they represent a much smaller proportion of circulating white blood cells (<1%) and are not the predominant cell type elevated in allergic responses 2
Monocytes (Option C):
- Monocytes are involved in chronic inflammation and wound healing but are not the primary responders in acute allergic reactions 2
Neutrophils (Option D):
- Neutrophils would be elevated in bacterial infections or acute inflammatory responses, but bee stings trigger allergic rather than infectious inflammation 3
- A critical pitfall is mistaking early allergic swelling for cellulitis and inappropriately treating with antibiotics when the mechanism is mediator release, not infection 3, 4
Clinical Context
The question tests understanding of hypersensitivity reaction patterns:
- Type I (IgE-mediated) hypersensitivity = eosinophils (bee stings, allergic reactions)
- Type II (cytotoxic) = neutrophils (transfusion reactions)
- Type III (immune complex) = neutrophils (serum sickness)
- Type IV (delayed) = lymphocytes and monocytes (contact dermatitis)
Since bee venom allergy is definitively an IgE-mediated Type I hypersensitivity reaction 1, 2, eosinophils are the expected elevated cell type.