Phytophotodermatitis Clinical Presentation

Updated: Nov 04, 2021
  • Author: William P Baugh, MD; Chief Editor: William D James, MD  more...
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Phytophotodermatitis (PPD) has been recorded for thousands of years and can be dated back through Egyptian history. It may be seen described in the Ebers Papyrus and was mistaken to be vitiligo. The common medicinal treatment for phytophotodermatitis was ground Elder herb. [16]

In current practice, the patient's history is essential in making the correct diagnosis of phytophotodermatitis. The clinician must be aware that this entity exists and inquire about contact with fruits or plants. This is particularly true if the patient complains of a painful or burning sensation rather than pruritus (which is commonly associated with allergic contact dermatitis). The patient's hobbies, recreational activities, and/or occupation may give essential clues to the most likely culprits.

Phytophotodermatitis most commonly occurs in the spring and the summer when furocoumarins are at their highest concentration in plants and when UV exposure is greatest for patients. For instance, children playing outdoors may come in contact with meadow grass of the Umbelliferae family.

Agricultural workers may develop phytophotodermatitis when picking parsley (Cymopteris watsonii), parsnips (Pastinaca sativa), celery (Apium graveolens), and/or carrots (Daucus carota). The resulting photocutaneous reaction in this group has been called harvester's dermatitis and is primarily due to exposure to Umbellifers. Another report describes an outbreak of "strimmer rash" in several grounds operatives who had all undertaken grass-cutting duties. The affecting agent was likely giant hogweed, also from the Umbellifers.

Cneoridium dumosum is a plant found along the southwestern coastal United States to which hikers may be exposed, resulting in phytophotodermatitis. Patients are often attracted to this plant by its scented white flower and red berries.

Bartenders and grocers classically develop phytophotodermatitis due to exposure to limes and celery, respectively. [17, 18]

Several reports describe patients creating fig leaf decoctions to use as "tanning lotions" or "suntan promoters." Fig leaves (Ficus carica or Ficus benjamina) are either ground up, boiled, or mixed with oil and then applied on the skin. [19, 20] Patients reported having found these decoction recipes from magazines and/or friends.

One report describes a patient rubbing the juice of medicinal limes (Citrus hystrix) onto the skin as a treatment for insect bites and as an insect repellent, which subsequently resulted in phytophotodermatitis.

Another report describes a patient rubbing the juice of medicinal lime (C hystrix) onto the scalp hair to dye his hair. The juice trickled in between his fingers onto the back of his hands and down the arms to the elbows, where the patient developed phytophotodermatitis.

One case of iatrogenic phytophotodermatitis resulted from ingestion of an herbal remedy prescribed for chronic hand dermatitis. [21] Plant fragments contained in the herbal mix included extracts from Compositae, a member of the daisy family. No reports describe phytophotodermatitis after contact with members of the Compositae family. However, the action of boiling the plant mix may have possibly released high concentrations of intracellular furocoumarins.

One study assessed the potential of a small amount of psoralen in a normal diet to provoke phototoxicity in volunteers with skin types I and II. The study concluded that threshold erythema and phytophotodermatitis was unaffected by ingestion of this normal dietary amount of fresh parsnips. [22]

Another study reports on a 30-year-old man who trimmed the stems of a F pumila shrub while exposing his forearms, antecubital fossae, neck, and forehead. Within the following 3 days, the patient noticed eruptions appearing on the exposed areas. Six weeks following, the patient experienced confettilike hypomelanosis over the prior-unprotected areas of the skin. He was treated with clobetasol propionate cream.


Physical Examination

The primary skin lesion of phytophotodermatitis may range from delayed erythema (24-48 h) to frank blisters. The skin lesions are limited to the areas in contact with furocoumarin and with sunlight exposure. The primary lesion is often not seen by the physician because of the transient nature of the reaction. Rather, the patient presents with late skin changes that become apparent after 72 hours.

Late skin lesions

Bizarre inflammatory patterns and linear streaks of hyperpigmentation are key clues to diagnosing phytophotodermatitis. These patterns often result from brushing against a plant's stems or leaves while outdoors or from the liquid spread of lime juice over the hand or down the forearm. A handprint pattern from lime juice contact is not uncommon. See the images below.

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.
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.

Furthermore, a buckshot spray over exposed surfaces is commonly seen in association with the use of string trimmers (weed-whackers) when unwanted weeds possessing furocoumarins are cleared from a field or a yard.

Skin distribution

Phytophotodermatitis is most commonly found on skin sites exposed to plants and sunlight; these include such areas as the arms and the legs, but it may occur anywhere.

Skin color

Skin color varies depending on the patient's underlying skin tone and the degree of the reaction. However, as previously stated, the acute phase of phytophotodermatitis manifests as erythema, and the end stage manifests as postinflammatory hyperpigmentation, as shown below.

The 2-month follow-up picture of a patient with a The 2-month follow-up picture of a patient with a drip-pattern blister formation on the dorsal forearm demonstrates the potential postinflammatory pigmentation changes and scarring that may occur with severe blistering of phytophotodermatitis.