Delayed Inflammatory Response Following Hymenoptera Sting
Case at a Glance
A 23-year-old male presented with delayed onset erythema, swelling, and warmth at the site of a bee sting on his forearm, raising concern for secondary bacterial infection versus extended allergic reaction.
Patient's Story
The patient reported being stung by a bee on his left forearm approximately 24 hours prior to presentation. Initially, the sting site appeared unremarkable with minimal local reaction. However, approximately 18-20 hours post-sting, he noticed progressive swelling, erythema, and warmth developing at the site. The area became pruritic with a sensation of pressure but remained non-tender. He denied fever, chills, malaise, or systemic symptoms. No lymphangitic streaking was observed, and the erythematous borders appeared stable without progressive expansion.
Initial Assessment
Physical examination revealed a 23-year-old male in no acute distress. Vital signs were within normal limits, including afebrile status. Local examination of the left forearm showed a circumscribed area of erythema and edema measuring approximately 4-5 cm in diameter surrounding the central sting site. The area was warm to palpation and mildly indurated but non-tender. No purulent drainage, lymphangitic streaking, or regional lymphadenopathy was present. The patient appeared well-hydrated with normal skin turgor elsewhere.
The Diagnostic Journey
The clinical presentation posed a diagnostic challenge between delayed-type hypersensitivity reaction to hymenoptera venom versus early cellulitis. The timing of symptom onset (delayed by nearly 24 hours), absence of systemic symptoms, stable borders of erythema, and lack of significant tenderness favored a large local reaction rather than bacterial superinfection. However, given the potential for serious complications if cellulitis was present, empirical antibiotic therapy was considered.
Final Diagnosis
Large local reaction to hymenoptera sting with consideration for early cellulitis requiring clinical monitoring.
Treatment Plan
The patient was prescribed cephalexin 500mg four times daily for 7 days as empirical coverage for potential secondary bacterial infection. Instructions were provided for symptomatic management including cool compresses, elevation of the affected extremity, and oral antihistamines for pruritus. The patient was counseled on signs requiring immediate medical attention including fever, spreading erythema, red streaking, or worsening pain.
Outcome and Follow-up
The patient was advised to monitor symptoms closely and return for reassessment if clinical deterioration occurred. Given the absence of systemic symptoms, stable appearance of the lesion, and patient's immunocompetent status, conservative management with close observation was deemed appropriate. Follow-up in 48-72 hours was recommended if symptoms persisted or worsened, with earlier return if concerning features developed.