Abstract
The correct answer is B: phytophotodermatitis. As suggested by the term, exposure to a light-sensitizing compound from plants (a furocoumarin) and UV light is required to cause this reaction. The acute eruption can range from minimal erythema to marked red edema and vesiculation within 24 hours after initial exposure. The rash is typically nonpruritic but can be painful. As the acute rash fades, hyperpigmentation appears which can last months to years [1].
While the features of the rash are characteristic, the distribution and shape are widely variable. The well-demarcated erythema, edema, and bullae appear in bizarre patterns on sun-exposed skin consistent with the area of plant exposure. Digitate or drip-like patterns may occur from citrus or celery juice that drips during food preparation. Linear patterns may occur from brushing up against outdoor plants such as wild parsnip or hogweed. While classic cases involve obvious sun exposure outdoors, window glass does not block the ultraviolet A waves that cause the phototoxic reactions of furocoumarins [2].
Citation
Barbante LTK, Barlow LCDRT and Eng-Kulawy LTJ. Blistering Perioral Rash in an Infant. SM Dermatolog J. 2017; 3(2): 1015.