Differential Diagnosis for the 9-year-old Boy with Oozing Skin Lesions
- Single most likely diagnosis:
- Contact dermatitis (likely due to exposure to plants such as poison ivy, oak, or sumac during the camping trip). The linear arrangement of the lesions and the presence of a well-demarcated tan line suggest an external allergen or irritant causing the reaction.
- Other Likely diagnoses:
- Insect bites or stings: The patient's recent camping trip and application of insect repellents increase the likelihood of insect bites, which could cause erythema, vesicles, and pruritus.
- Phytophotodermatitis: This condition occurs when the skin reacts to certain plant chemicals (like those in lime or wild parsnip) after exposure to sunlight, leading to blistering and skin discoloration.
- Irritant contact dermatitis: Exposure to substances like soap, detergent, or other chemicals during the camping trip could cause skin irritation, especially if the skin was not properly rinsed.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Cellulitis: A bacterial infection of the skin that could present with erythema, swelling, and warmth, and may require prompt antibiotic treatment.
- Necrotizing fasciitis: A severe bacterial infection that can cause pain, swelling, and skin lesions, and is a medical emergency.
- Rare diagnoses:
- Leptospirosis: A bacterial infection that can be contracted through contact with contaminated water, and may cause skin lesions, among other symptoms.
- Erythema multiforme: An immune-mediated condition that can cause skin lesions, often in response to an infection or medication.
- Zoster (shingles): Although less common in children, zoster can cause a painful rash, usually in a dermatomal distribution.