Localized immune response to allergens, causing localized hives, itching, nasal congestion, or watery eyes.
Step-by-Step Guidance
Identify what caused the allergy (food, pollen, cat hair) and distance the patient from it.

Administer an over-the-counter antihistamine (e.g. diphenhydramine or cetirizine) following dosage guidelines.

Place a cool, damp washcloth over itchy skin or hives to reduce swelling and irritation.

If skin is itchy, apply a thin layer of 1% hydrocortisone cream to calm localized inflammation.

Watch the patient closely. Ensure they do not develop coughing, throat tightness, or facial swelling.

12 - 24 hours
Timeline is typical for uncomplicated healing. Always follow doctor guidance.