Delayed onset 12 to 72 hours after exposure supports type IV hypersensitivity
Linear streaks with vesicles suggest urushiol exposure
Hands and face are common sites due to frequent exposures
Recurrent dermatitis in same location suggests repeated allergen contact
PITFALLS
Common errors
Assuming antibiotics needed for erythematous pruritic plaques without warmth or tenderness
Using topical antihistamines or topical antibiotics that can worsen allergic dermatitis
Under-treating severe poison ivy with inadequate systemic steroid duration
Missing periocular involvement requiring ophthalmology input for eyelid disease
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.