Hyperpigmentation and vesicles after beach vacation

Diagnosis: Phytophotodermatitis

This patient has phytophotodermatitis, a phototoxic dermatologic reaction that occurs with exposure to ultraviolet light after contact with certain plants. Hyperpigmentation and vesicle or bullae formation are hallmarks of the process.

The sun-sensitizing chemicals are furocoumarins, found in many plants (TABLE).¹ Psoralen, the same substance used in PUVA treatments, is one of the furocoumarins. These agents contact the skin when juice is released from the fruit or stem or by direct contact with leaves.²

This patient remembered eating fresh limes on the beach and posing for a photograph next to her fiancé, when he placed his right hand around her back and on her right thorax (FIGURE 1). Limes have a high concentration of psoralens and are often the culprit in phytophotodermatitis.^1,3 It is therefore incumbent on the clinician to know this and ask about lime and plant exposure when suspecting this diagnosis.

Erythema typically develops within 24 hours of sun exposure and contact with furocoumarin-containing plants. Vesicles or bulla may develop within 72 hours. Hyperpigmentation occurs over 1 to 2 weeks and can persist for 6 to 12 months. Hyperpigmentation can appear in bizarre streaks or patterns depending on where the chemicals contacted sun-exposed skin. Areas that have formed bulla typically exfoliate within 10 to 14 days.³

TABLE
Common furocoumarin-containing plants¹