Differentials
Phytodermatitis
SIGNS / SYMPTOMS
There are a large number of plants that can cause acute contact dermatitis. They include Primula obconica and Asteraceae (sunflower family).[1][2][3]
The appearance of the rash may be indistinguishable from that of poison ivy, oak, and sumac.
INVESTIGATIONS
Clinical history of exposure to other plant species. Confirmed by botanical identification.
Phytophotodermatitis
SIGNS / SYMPTOMS
There are several plants that can cause toxic reactions following exposure to the sun.
Examples are Umbelliferae (e.g., celery, hogweed), Moraceae (e.g., fig), and Rutaceae (e.g., lime).[1][3][4]
Reaction occurs if the contaminated skin is exposed to sunlight. Sun-protected sites should not be affected.
INVESTIGATIONS
Botanical examination of the plant.
Allergic contact dermatitis
SIGNS / SYMPTOMS
Resulting from exposure to another allergen. Symptoms are the same, but areas affected may differ and no linear streak pattern of blisters and vesicles occurs.
Allergens include fragrance, nickel, and rubber.
INVESTIGATIONS
Patch testing; uses standard trays of most common allergens. Patch readings taken at 48 hours and between 72 hours and 1 week. Positive result shows inflammation graded 1+ to 3+ after 2 to 7 days.
Cellulitis or erysipelas
SIGNS / SYMPTOMS
Periorbital edema with fever; affected areas not itchy; lack of vesicles or blisters elsewhere.
INVESTIGATIONS
Skin swabs for microbiology positive for bacterial infection.
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