Logo of bumcprocBaylor University Medical Center ProceedingsAbout the JournalBaylor Health Care SystemSubmit a Manuscript
Proc (Bayl Univ Med Cent). 2000 Oct; 13(4): 405–406.
PMCID: PMC1312240

Hyperpigmented macules and streaks

Phytophotodermatitis is an ultraviolet-induced contact dermatitis due primarily to plant- (= phyto), fruit-, or vegetable-derived photosensitizing compounds such as furocoumarins (psoralens). Two prerequisites must be filled for phytophotodermatitis to occur: 1) the skin must have had contact with a sensitizing phototoxin (allergen), and 2) there must be subsequent exposure to ultraviolet radiation (1). Psoralens may be transferred directly when leaves, rinds, or juice come into contact with the skin or indirectly through person-to-person contact. The majority of these phototoxins are activated by ultraviolet light in the long-wave or ultraviolet A (UVA) spectrum (320–400 nm) (2).

Figures Figures11 and 22 are examples of “margarita photodermatitis” in 2 different patients (1). While sunbathing at the beach and preparing margaritas, our patients squeezed limes, which left juice on their skin. Juice on the hands is easily spread or even dripped onto distant sites or other people. Lime juice contains furocoumarin, a lipid-soluble 8-methoxypsoralen. After sunbathing (a potent source of UVA), the 8-methoxypsoralen covalently binds to keratinocyte DNA (forming cyclobutane dimers), producing irreversibly damaged DNA (3).

Figure 1
Bizarre streaks and linear erythematous vesicular plaques with hyper- pigmentation on the abdomen.
Figure 2
Linear erythematous vesicular plaques with hyperpigmentation on the arm.


The most common allergens causing phytophotodermatitis belong to the following plant families: Umbelliferae (celery, pars-ley, parsnips), Rutaceae (limes, lemons), and Moraceae (figs) (4). Twelve to 36 hours after psoralen contact and subsequent ultra- violet exposure, erythema and vesicle formation begin, and the patient may experience a burning pain. The erythema lasts 3 to 5 days and is replaced by hyperpigmentation, which may be intense and take months to resolve. Permanent scarring is rare unless secondary infection occurs during the vesicular phase.

Classic presentations of phytophotodermatitis include bizarre and linear erythema, vesicles and bullae, and spots or streaks of hyperpigmentation. Particularly helpful clues to the diagnosis include “drip marks”; irregular, bizarre “sunburns”; and handprint shapes (5). The most commonly involved areas include the dorsa of the hands, wrists, forearms, and lower legs. Several groups are at risk for phytophotodermatitis, including bartenders, farmers, grocers, and college students (6). “Celery burn” is seen most frequently in grocers and is due to the high concentration of psoralens in the green leafy portion of celery (6).

Ingestion of psoralen-containing vegetables in sufficient quantities may, on occasion, also lead to generalized phototoxicity in patients exposed to UVA (7).


Phytophotodermatitis is a clinical diagnosis that is suggested by atypical, bizarre, sunburnlike reactions with hyperpigmentation (2). A careful history should include possible contact with any of the common plants listed above. Use of “folk” remedies, such as lemon or lime juice for insect bites, should also be explored (5, 8, 9).

Differential diagnosis

Phytophotodermatitis can be confused with several other conditions including allergic contact dermatitis, infectious lymphangitis, hematologic/oncologic diseases, fungal infections, erythema multiforme, impetigo, cellulitis, jellyfish envenomation, and arthropod bites (5, 10, 11). Additionally, children may acquire lesions from contact with other people who have juice on their hands. These lesions may be difficult to distinguish from child abuse (2). Interestingly, pseudophytophotodermatitis (indistinguishable from phytophotodermatitis) can also be caused by celery infected with a fungus (Sclerotinia sclerotiorum). The fungus produces 8-methoxypsoralen as well as other furocoumarins (4).


There is no specific treatment for this condition (2). During the acute phase, cold wet compresses and oral salicylates are given for pain and blistering (6). In addition, potent topical steroids will facilitate the clearing of the erythema and vesicles and possibly reduce subsequent hyperpigmentation, which may be further improved by the use of hydroquinones after the acute phase (5).


1. Abramowitz AI, Resnick KS, Cohen KR. Margarita photodermatitis. N Engl J Med. 1993;328:891. [PubMed]
2. Bergeson PS, Weiss JC. Picture of the month. Phytophotodermatitis. Arch Pediatr Adolesc Med. 2000;154:201–202. [PubMed]
3. Vassileva SG, Mateev G, Parish LC. Antimicrobial photosensitive reactions. Arch Intern Med. 1998;158:1993–2000. [PubMed]
4. Stoner JG, Rasmussen JE. Plant dermatitis. J Am Acad Dermatol. 1983;9:1–15. [PubMed]
5. Goskowicz MO, Friedlander SF, Eichenfield LF. Endemic “lime” disease: phytophotodermatitis in San Diego County. Pediatrics. 1994;93:828–830. [PubMed]
6. Webb JM, Brooke P. Blistering of the hands and forearms. Phytophoto- dermatitis. Arch Dermatol. 1995;131:834–838. [PubMed]
7. Puig L. Pharmacodynamic interaction with phototoxic plants during PUVA therapy. Br J Dermatol. 1997;136:973–974. [PubMed]
8. Koh D, Ong C-N. Phytophotodermatitis due to the application of Citrus hystrix as a folk remedy. Br J Dermatol. 1999;140:737–738. [PubMed]
9. Wessner D, Hofmann H, Ring J. Phytophotodermatitis due to Ruta graveolens applied as protection against evil spells. Contact Dermatitis. 1999;41:232. [PubMed]
10. Ahmed I, Charles-Holmes R. Phytophotodermatitis mimicking superficial lymphangitis. Br J Dermatol. 2000;142:1069. [PubMed]
11. Burnett JW, Horn TD, Mercado F, Niebyl PH. Phytophotodermatitis mimicking jellyfish envenomation. Acta Derm Venereol (Stockh) 1988;68:168–171. [PubMed]

Articles from Proceedings (Baylor University. Medical Center) are provided here courtesy of Baylor Health Care System
PubReader format: click here to try


Save items

Related citations in PubMed

See reviews...See all...


  • PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...