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Case Report

A Case of Unilateral Hyperpigmentation

Department of Dermatology, Incheon St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Korea
Department of Biomedicine & Health Sciences, The Catholic University of Korea, 222 Banpo-dearo, Seocho-gu, Seoul 06591, Korea
Author to whom correspondence should be addressed.
Dermato 2021, 1(1), 26-30;
Submission received: 31 May 2021 / Revised: 27 June 2021 / Accepted: 29 June 2021 / Published: 1 July 2021


Phytophotodermatitis is a cutaneous phototoxic reaction resulting from contact with plant compounds such as furocoumarin in citrus fruits, followed by exposure to ultraviolet light. Erythema and vesicles appear on the contact area, followed by hyperpigmented lesions. Hyperpigmentation may exist for weeks to months before fading but can remain up to several years. Diagnosis is often challenging due to the variety of clinical presentations, and it is not always easy to identify trigger exposures. A detailed history is key to diagnosis. We herein report a case of lime-induced phytophotodermatitis which was initially mistaken for unilateral lentiginosis. The patient underwent Q-switched Nd:YAG laser and intense pulsed light (IPL) treatment with immediate improvement.

1. Introduction

Phytophotodermatitis is a non-immunologic cutaneous reaction caused by exposure to photosensitizing compounds in plants and subsequent exposure to sunlight [1]. Furocoumarin is a photosensitizing substance produced by certain plants including lime, celery, fig and parsnip [2]. Clinical findings evolve from the initial painful erythema and edema to blisters and late hyperpigmentation. Diagnosis is challenging and is often misdiagnosed as other skin conditions including allergic contact dermatitis and burns (early) and pigmentary disorders (late), especially when a patient fails to mention the relevant background. Treatment is symptomatic, the rash being resolved in weeks, though hyperpigmentation can persist for months. Herein, we present a case of lime-induced phytophotodermatitis which was initially mistaken for unilateral lentiginosis and showed drastic improvement after a single session of Q-switched Nd:YAG laser and intense pulsed light treatment.

2. Case

A 26-year-old woman presented with asymptomatic, diffuse, brown macules and patches on the right hand and arms for weeks (Figure 1). The patient did not have any past medical or dermatologic problems. On histopathologic examination, mild elongation of the rete ridges and increased pigmentation of the basal keratinocytes with few scattered dermal melanophages were shown (Figure 2). Based on the brief clinical exam and pathology, the patient was presumed to have unilateral lentiginosis and underwent a single session of intense pulsed light (IPL) and Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser treatment. The patient was advised to use sunscreen to minimize laser-related post-inflammatory hyperpigmentation (PIH).
After two months, the hyperpigmented lesions showed significant improvement, which was surprising considering the nature of lentigines which normally require multiple treatment (Figure 3). On further history taking, the patient was said to have made a trip to Vietnam where she squeezed and touched lime exclusively with her right hand. The patient revealed that the area first showed erythema and a few vesicles which later-on turned into pigmented spots. From the history and prompt response to treatment we made a final diagnosis of lime-induced phytophotodermatitis, which was initially overlooked.

3. Discussion

Phytophotodermatitis is a phototoxic reaction that occurs after exposure to plant-derived photosensitizing compounds followed by ultraviolet A (UVA 320–380 nm) radiation [1]. Various plants including citrus fruit, celery, wild parsnip, carrot, and fig contain phototoxic agents that precipitate phototoxic reactions [2]. Furocoumarin is such a compound and normally protects plants against the attack of fungal pathogens [3]. When furocoumarin is ingested or applied to the skin with the skin being further exposed to UVA, cellular damage is triggered, either directly through a photosensitizer-target interaction or indirectly through the generation of reactive oxygen species (ROS) [4].
After the first description of phytophotodermatitis in 1942 by Klaber [5], there have been a number of case reports on lime-induced phyophotodermatitis (Table 1). The epidemiology is not well known, but most cases have been reported in cultures that widely consume limes (i.e., Mojito).
Phytophotodermatitis usually begin as erythema with subsequent blistering of the contact area, 12–36 h after furocoumarin exposure to UVA. Due to melanocyte hypertrophy, increased melanosome density and melanocyte dendricity, and dermal melanophages, hyperpigmented lesions may appear [6].
A detailed patient history is important in making a diagnosis, but patients sometimes do not disclose information because they think it is not relevant. Thus, it is important for the clinician to be aware of phytophotodermatitis because it is often misdiagnosed as allergic contact dermatitis, cellulitis, herpes simplex virus infection and even child abuse (early) and pigmentary disorders (late) [7].
There is limited evidence on the efficacy of treatment. Treatment is largely symptomatic, where a cold compress and topical steroids are sufficient for mild symptoms, whereas systemic steroids are indicated in severe cases. Hyperpigmentation may exist for weeks to months before fading but can persist up to several years if not properly managed [8].
Treatment options for the hyperpigmentation in phytophotodermatitis are similar to that of PIH from other causes. Topical agents such as hydroquinone and retinoids can be applied. Lasers that target melanin such as Q-switched Nd:YAG laser, as well as IPL, can be used successfully in persistent cases [9,10]. Although not routinely recommended, Q-switched Nd:YAG laser can be an option for those who want to improve their hyperpigmentation in a short period of time. In our case, the lesions disappeared shortly after a single session of Q-switched Nd:YAG and IPL.
If contact to the plants was recognized, the skin should be washed with water before exposure to sunlight. Additionally, as a preventive measure, we recommend vigorous photoprotection (i.e., sunscreen, physical sunshields) after having contact with plants containing furocoumarin. The importance of sunscreen is also emphasized after laser treatment to minimize the risk of PIH.

Author Contributions

Conceptualization, H.-S.K.; methodology, Y.H.; validation, S.-H.C., J.-D.L. and Y.-R.W.; formal analysis, Y.H.; investigation, Y.H., S.-H.L.; resources, M.C.; data curation, Y.H.; writing—original draft preparation, Y.H.; writing—review and editing, Y.-R.W., H.-S.K.; visualization, Y.H.; supervision, H.-S.K.; project administration, M.C. All authors have read and agreed to the published version of the manuscript.


This research received no external funding.

Institutional Review Board Statement

The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board of Incheon St. Mary’s hospital, Incheon, South Korea (OC21ZISI0047, 21 May 2021).

Informed Consent Statement

Informed consent was obtained from all subjects involved in the study.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.


  1. Pomeranz, M.K.; Karen, J.K. Phytophotodermatitis and Limes. N. Engl. J. Med. 2007, 357, e1. [Google Scholar] [CrossRef] [PubMed]
  2. Abugroun, A.; Gaznabi, S.; Natarajan, A.; Daoud, H. Lime-induced phytophotodermatitis. Oxf. Med. Case Rep. 2019, 2019, 470–472. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  3. Bonamonte, D.; Foti, C.; Lionetti, N.; Rigano, L.; Angelini, G. Photoallergic contact dermatitis to 8-methoxypsoralen in Ficus carica. Contact Dermat. 2010, 62, 343–348. [Google Scholar] [CrossRef] [PubMed]
  4. Son, J.-H.; Jin, H.; You, H.-S.; Shim, W.-H.; Kim, J.-M.; Kim, G.-W.; Kim, H.-S.; Ko, H.-C.; Kim, M.-B.; Kim, B.-S. Five Cases of Phytophotodermatitis Caused by Fig Leaves and Relevant Literature Review. Ann. Dermatol. 2017, 29, 86–90. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  5. Klaber, R. Phytophotodermatitis. Br. J. Dermatol. 1942, 54, 193–211. [Google Scholar] [CrossRef]
  6. Walling, A.; Walling, H.W. Phytophotodermatitis induced by wild parsnip. Dermatol. Online J. 2018, 24. [Google Scholar] [CrossRef]
  7. Carlsen, K.; Weismann, K. Phytophotodermatitis in 19 children admitted to hospital and their differential diagnoses: Child abuse and herpes simplex virus infection. J. Am. Acad. Dermatol. 2007, 57 (Suppl. 5), S88–S91. [Google Scholar] [CrossRef] [PubMed]
  8. Walling, A.L.; Walling, H.W. Prolonged hyperpigmentation induced by wild parsnip phytophotodermatitis. Arch. Clin. Exp. Dermatol. 2020, 2, 116. [Google Scholar]
  9. Tse, Y.; Levine, V.J.; A McClain, S.; Ashinoff, R. The removal of cutaneous pigmented lesions with the Q-switched ruby laser and the Q-switched neodymium: Yttrium-aluminum-garnet laser. A comparative study. J. Dermatol. Surg. Oncol. 1994, 20, 795–800. [Google Scholar] [CrossRef] [PubMed]
  10. Babilas, P.; Schreml, S.; Szeimies, R.-M.; Landthaler, M. Intense pulsed light (IPL): A review. Lasers Surg. Med. 2010, 42, 93–104. [Google Scholar] [CrossRef] [PubMed]
  11. Coffman, K.; Boyce, W.T.; Hansen, R.C. Phytophotodermatitis Simulating Child Abuse. Arch. Pediatr. Adolesc. Med. 1985, 139, 239–240. [Google Scholar] [CrossRef] [PubMed]
  12. Wagner, A.M.; Wu, J.J.; Hansen, R.C.; Nigg, H.N.; Beiere, R.C. Bullous Phytophotodermatitis Associated with High Natural Concentrations of Furanocoumarins in Limes. Am. J. Contact. Dermat. 2002, 13, 10–14. [Google Scholar] [CrossRef] [PubMed]
  13. Hankinson, A.; Lloyd, B.; Alweis, R. Lime-induced phytophotodermatitis. J. Community Hosp. Intern. Med. Perspect. 2014, 4. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  14. Mioduszewski, M.; Beecker, J. Phytophotodermatitis from making sangria: A phototoxic reaction to lime and lemon juice. Can. Med. Assoc. J. 2015, 187, 756. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  15. Galvan-Perez del Pulgar, J.I.; Linares-Barrios, M.; Galvañ-Pozo, J.I., Jr. Acropigmentation of the Dorsum of the Hands from Preparing Mojitos: A Lime-Induced Phytophotodermatosis. Actas Dermosifiliogr. 2016, 107, 253–255. [Google Scholar] [CrossRef] [PubMed]
  16. Snaidr, V.A.; Lowe, P.M. Phytophotodermatitis from lime juice. Med. J. Aust. 2017, 207, 328. [Google Scholar] [CrossRef] [PubMed]
  17. Safran, T.; Kanevsky, J.; Ferland-Caron, G.; Mereniuk, A.; Perreault, I.; Lee, J. Blistering phytophotodermatitis of the hands after contact with lime juice. Contact Dermat. 2017, 77, 53–54. [Google Scholar] [CrossRef] [PubMed]
  18. Fitzpatrick, J.K.; Kohlwes, J. Lime-Induced Phytophotodermatitis. J. Gen. Intern. Med. 2018, 33, 975. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  19. Wang, S.; Ma, L. Lime-induced phytophotodermatitis occurred in two family members presented as hyperpigmentation. Photodermatol. Photoimmunol. Photomed. 2021. [Google Scholar] [CrossRef] [PubMed]
  20. Hamid, R.N.; I Aleisa, A.; Elston, D.M. Pink Patches with a Hyperpigmented Rim. Cutis 2021, 107, 79–86. [Google Scholar] [CrossRef] [PubMed]
Figure 1. (a) Right arm (lesion): There are diffuse brown macules and patches, sparing the area under the ring on the third finger. (b) Left arm (control).
Figure 1. (a) Right arm (lesion): There are diffuse brown macules and patches, sparing the area under the ring on the third finger. (b) Left arm (control).
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Figure 2. (a) Histopathological examination of the lesion reveals mild rete ridge elongation, increased pigmentation of basal keratinocytes and scattered dermal melanophages (H&E stain, ×40). (b) Increase in basal melanin (Fontana-Masson) and (c) Dermal melanophages (S-100) are seen.
Figure 2. (a) Histopathological examination of the lesion reveals mild rete ridge elongation, increased pigmentation of basal keratinocytes and scattered dermal melanophages (H&E stain, ×40). (b) Increase in basal melanin (Fontana-Masson) and (c) Dermal melanophages (S-100) are seen.
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Figure 3. (a) Before laser treatment and (b) After a single session of Q-switched Nd:YAG and IPL, at 2 months follow-up.
Figure 3. (a) Before laser treatment and (b) After a single session of Q-switched Nd:YAG and IPL, at 2 months follow-up.
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Table 1. Review of lime-induced phytophotodermatitis in the literature.
Table 1. Review of lime-induced phytophotodermatitis in the literature.
No.PublicationAge (yr)/SexCutaneous FindingsLocationContact History
1Coffman et al. [11] 19854/FHyperpigmentationChest, upper back, and wristSqueezing lime
2Coffman et al. [11] 19851/MHyperpigmentationChest and backSqueezing lime
3Wagner et al. [12] 20026/MErythema and bullaeHandSqueezing lime
4Pomeranz et al. [1] 200723/FErythema and bullaeBack, arm, and hand Preparing mojitos
3Hankinson et al. [13] 201424/FErythema and bullaeHandSqueezing lime while cooking
4Mioduszewski and Beecker [14] 201526/FErythema and bullaeHandSqueezing lime while making sangria
5Galvañ-Pérez et al. [15] 201623/FHyperpigmentationHandPreparing mojitos
6Galvañ-Pérez et al. [15] 201625/FHyperpigmentationHandPreparing mojitos
7Galvañ-Pérez et al. [15] 201631/FHyperpigmentationHandPreparing mojitos
8Galvañ-Pérez et al. [15] 201619/FHyperpigmentationHandPreparing mojitos
9Galvañ-Pérez et al. [15] 201641/MHyperpigmentationHandPreparing mojitos
10Galvañ-Pérez et al. [15] 201640/MHyperpigmentationHandPreparing mojitos
11Galvañ-Pérez et al. [15] 201621/FHyperpigmentationHandPreparing mojitos
12Galvañ-Pérez et al. [15] 201614/FHyperpigmentationHandPreparing mojitos
13Galvañ-Pérez et al. [15] 201616/FHyperpigmentationHandPreparing mojitos
14Snaidr and Lowe [16] 201736/FErythema and bullaeHandLime juice
15Safran et al. [17] 201717/FErythema and bullaeHandSqueezing lime while cooking
16Fitzpatrick et al. [18] 201831/MHyperpigmented maculesHandSqueezing lime while mixing margaritas
17Abugroun A et al. [2] 201926/MErythema and bullaeHandSqueezing lime
18Wang and Ma [19] 20216/FHyperpigmented maculesShoulder Squeezing lime during the hot spring
19Wang and Ma [19] 2021-/M (No.18′s father)Hyperpigmented maculesUpper backSqueezing lime during the hot spring
20Hamid et al. [20] 202125/MHyperpigmented maculesHandDrinking beer with lime
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Han, Y.; Lee, S.-H.; Cho, M.; Cho, S.-H.; Lee, J.-D.; Woo, Y.-R.; Kim, H.-S. A Case of Unilateral Hyperpigmentation. Dermato 2021, 1, 26-30.

AMA Style

Han Y, Lee S-H, Cho M, Cho S-H, Lee J-D, Woo Y-R, Kim H-S. A Case of Unilateral Hyperpigmentation. Dermato. 2021; 1(1):26-30.

Chicago/Turabian Style

Han, Yujin, Se-Hoon Lee, Minah Cho, Sang-Hyun Cho, Jeong-Deuk Lee, Yu-Ri Woo, and Hei-Sung Kim. 2021. "A Case of Unilateral Hyperpigmentation" Dermato 1, no. 1: 26-30.

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