Picture of the Month FREE

Figure 1 and Figure 2. The skin lesions on the trunk conform precisely to the borders of the bathing suit. Bullae and vesicles, some linear in arrangement, are set on an erythematous base. The history revealed that the girl and her siblings had eaten limes, the juice of which had run down onto the chest and abdomen. The children were exposed to sunlight.

Figure 3 and Figure 4. Hyperpigmented patches and macules are present on both arms. The skin lesions appeared shortly after harvesting ornamental oranges.

Phytophotodermatitis refers to a skin eruption that results from the interaction of radiant energy from the sun with photosensitizing compounds found in various plants. These agents that potentially produce phototoxic effects are present in many plant varieties, including several isomers of psoralens (furocoumarins). The psoralens form phototoxic compounds on exposure to UV-A radiation (wavelengths of 320-400 nm).¹ The compounds cause direct damage to the DNA of epidermal cells, resulting in reactions that range from macular erythema or hyperpigmentation to blistering lesions, depending on the extent of exposure. The figures show the spectrum of skin reactions that may be seen.

The acute phase of phytophotodermatitis is often characterized by erythematous plaques, vesicles, and bullae, much like a severe sunburn. Lesions may simply become erythematous or appear as hyperpigmented patches without a preceding erythematous phase. The shape of the lesions is often unusual, sometimes resembling streaks from dripping juices containing the phototoxic compounds. The hands and mouth are often extensively affected secondary to eating and handling. The unusual configuration of lesions is often a clue to the diagnosis. The skin eruptions may appear hours to days after exposure.

The plants that are the most common causes of this dermatitis are limes, lemons, and celery. Natural grasses, carrots, oranges, parsley, parsnips, and several plants in the family Compositae, such as sagebrush, goldenrod, chrysanthemum, ragweed, and cocklebur, may also contain natural psoralens.² Tobacco, figs, garlic, hot peppers, and hyacinth and daffodil bulbs are among the other offenders.

Phytophotodermatitis is a clinical diagnosis. The sunburnlike reactions with unusual configurations should suggest the diagnosis. A history of contact with one of the offending plants and subsequent sunlight exposure should be sought. The unusual nature of these skin lesions may suggest child abuse, scalding, cellulitis, and fungal infections.^1,3

There is no specific treatment for this reaction. In severe cases, analgesics, antihistamines for itching, and wet compresses may be used. Blistered areas should be kept clean to prevent secondary infection. The hyperpigmentation fades over time as it does in sunburned skin.

Accepted for publication March 31, 1999.

Corresponding author: Paul S. Bergeson, MD, Phoenix Children's Hospital, 909 E Brill St, Phoenix, AZ 85006.