Differential Diagnosis for Rash and Eyelid Swelling after Woods Exposure with Poison Ivy Allergy
- Single most likely diagnosis:
- Contact dermatitis due to poison ivy: This is the most likely diagnosis given the patient's history of allergy to poison ivy and recent exposure to the woods, where poison ivy is commonly found. The rash and eyelid swelling are consistent with an allergic reaction to urushiol, the oil found in poison ivy.
- Other Likely diagnoses:
- Allergic contact dermatitis due to other plants (e.g., poison oak, poison sumac): Similar to poison ivy, these plants contain urushiol or similar oils that can cause an allergic reaction.
- Insect bites or stings: Exposure to the woods increases the risk of insect bites or stings, which can cause localized reactions, including rashes and swelling.
- Irritant contact dermatitis: This could be due to exposure to other substances in the woods, such as certain plants, dirt, or chemicals, that irritate the skin.
- Do Not Miss diagnoses:
- Angioedema: Although less likely, angioedema is a potentially life-threatening condition that can cause swelling of the face, lips, and eyelids. It can be triggered by allergies, including those to plants or insects.
- Anaphylaxis: This is a severe, life-threatening allergic reaction that requires immediate medical attention. Symptoms can include rash, swelling, difficulty breathing, and a drop in blood pressure.
- Rare diagnoses:
- Erythema multiforme: A skin condition characterized by target-like lesions, which can be triggered by various factors, including infections and medications.
- Photosensitive reactions: Certain conditions, such as porphyria or polymorphic light eruption, can cause skin reactions after sun exposure, which might be exacerbated by time spent in the woods.