Phytophototoxin Poisoning Clinical Presentation

Updated: Feb 16, 2019
  • Author: Toluwumi O Olafisoye , MD; Chief Editor: Sage W Wiener, MD  more...
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The history is essential in making the diagnosis of phytophotodermatitis (PPD). All of the following patient items may provide essential information to the health care provider [7, 18, 19, 20, 21, 22, 23, 24, 25, 26, 14, 27, 28] :

  • Employment history
  • Eating and drinking habits
  • Recreational activities
  • Tanning habits, including the use of herbal tanning lotions and citrus hair lighteners
  • Prescription and over-the-counter medications
  • Travel experience  

A phototoxic reaction can result from contact with a specific plant via skin exposure, or less commonly, ingestion, followed by exposure to sunlight. The rash often occurs in linear and odd patterns, including "handprints." The photos below show a reaction after exposure to a plant and sunlight. The second image is a close-up view of the rash. 

A 37-year-old white woman presented to the clinic A 37-year-old white woman presented to the clinic complaining of a rash on the medial part of her right thigh and left arm that was acquired after clearing some weeds in her yard. A phototoxic combination of sunlight and a psoralen-containing plant produced this bizarre linear vesicular eruption.
Closer clinical view of bizarre angulated vesicula Closer clinical view of bizarre angulated vesicular streaks, which occurred after contact with a plant and ultraviolet light exposure.

Onset of PPD is usually within 24-48 hours after sunlight exposure. Initial manifestations are often described as burning pain and erythema. These are followed by blistering, which occurs within 48 hours.

Pruritus is uncommon. The absence of pruritus helps distinguish PPD from allergic phytodermatitis (eg, toxicodendron dermatitis).

The irregular "burns" and handmark patterns produced, often without a clear-cut history, have been mistaken for child abuse. A good history is essential in differentiating the two in children. [29, 30, 31, 32]


Physical Examination

A usually sharp demarcation between normal covered skin and abnormal exposed skin is observed. The color of lesions may vary depending on the individual's underlying skin tone and the degree of exposure.

The initial manifestaiton is nonpruritic erythema of exposed areas. For example, a "burst" of skin lesions may been seen after contact with squirted lime juice or with sprayed plant materials onto an individual's uncovered arms or legs while utilizing a "weed whacker". Photos below show a rash caused by lime juice and subsequent sunlight exposure. The second photo was taken at follow-up visit.

A 26-year-old female airline flight attendant expo A 26-year-old female airline flight attendant exposed to lime while serving drinks en route to the Caribbean. During the Caribbean layover, she had significant sun exposure. The combination of lime juice and sun exposure led to a drip-pattern blister formation on the dorsal forearm consistent with phytophotodermatitis. This picture clearly delineates the potential severity of phytophotodermatitis with extensive blister formation.
The 2-month follow-up photo of the patient above d The 2-month follow-up photo of the patient above demonstrates the potential postinflammatory pigmentation changes and scarring that may occur with severe blistering of phytophotodermatitis.

Subsequently, edema develops, leading to vesicles, bullae, or both (usually within 24-72 h). Desquamation is possible.

Finally, dense hyperpigmentation may result from a melanocytic response. This can persist for several months. Finally, the affected area may remain hypersensitive to ultraviolet light for many years