This patient was squeezing lemons for lemonade over Easter weekend, and subsiquently developed these strange, punctate, round blotches her hands. A visit with me quickly identified her rash as phytophotodermatitis. This is a phototoxic reaction to contact with certain plants. Phytophotodermatitis generally occurs during in spring or summer following some outdoor activity on a sunny day during which there has been contact with one of the responsible plants. Its name has 3 components: phyto (plant), photo (light) and dermatitis (inflammatory rash). During the acute inflammatory stage, itchy blisters and reddened patches appear on exposed skin, usually the forearms or lower legs. These are often irregularly distributed and odd in shape. Linear lesions are characteristic. In some cases, the inflammatory phase is not observed. After a few days the redness and blistering settles down, but is replaced by unsightly and bizarre pigmentation at the same sites. The pigmentation is more pronounced in dark skin compared to fair skin. This postinflammatory pigmentation may persist for weeks to months Responsible plants include: parsley, parsnips, celery, carrots, figs, limes, lemon, oranges, and several species of wildflowers.
Contact with the plant, fruit or vegetable may have been brief and unnoticed. By the time pigmentation has occurred, the inflammatory phase of phytophotodermatitis is over. This means that anti-inflammatory treatments like topical steroids are only useful in the early phase of redness and blistering. The postinflammatory pigmentation that follows phytophotodermatitis responds poorly to treatment with bleaching creams. It fades gradually over weeks to months. Using covering clothing and broad spectrum sunscreens, affected skin should be protected from further sun exposure, which might cause the pigmentation to darken. It can be disguised using cosmetic camouflage make-up.
Dr. Cindy N. Berthelot, M.D. is a board certified dermatologist treating patients in the greater Houston community, including Clearlake, League City, Friendswood, Pasadena, Deer Park, Dickinson, Pearland, Alvin, Seabrook, Kemah, Webster, Galveston, Texas City, La Marque, and Santa Fe, Texas. To make an appointment with Dr. Berthelot, please contact us at 281.480.7272.