Dear Editors,
Phytophotodermatitis is a non-allergic contact dermatitis caused by exposure to furocoumarins, phototoxic agents found in certain plants, followed by exposure to sunlight [–]. Herein, we present a rare case of lime-induced phytophotodermatitis in a Japanese pediatric patient.
A 7-year-old boy with a history of food allergies and atopic dermatitis presented to our department with a 1-month history of a hand eruption. Four days before the onset of the skin lesion, he had squeezed limes. Three days prior to onset, he squeezed limes again and subsequently bathed in seawater while exposed to sunlight (Figure 1A). Erythematous lesions were first noted on the dorsal aspects of both thumbs and index fingers and subsequently developed into small vesicles, without pruritus or pain (Figures 1B,C). No skin lesions were observed on other sun-exposed areas or lime-exposed areas, including the face, neck, lower extremities, or palms. There was no history of exposure to potential contact allergens, such as rubber products, before the onset of the lesions.
FIGURE 1
At presentation, the erythema and vesicles had resolved, leaving well-demarcated pigmentation extending from the dorsal aspects of both thumbs to the medial sides of the index fingers, with confluent pigmentation on the third and fourth fingers of the left hand (Figure 1D). Based on the characteristic clinical course and history, a diagnosis of phytophotodermatitis was made. The patient was advised to apply emollients and practice photoprotective measures, and the skin lesions resolved without residual pigmentation 4 months after onset.
Phytophotodermatitis is primarily a clinical diagnosis and generally does not require additional examinations such as phototesting or photopatch testing []. The absence of lesions at sites exposed to either sunlight or lime alone argues against photosensitivity or lime-induced contact dermatitis, while the sharply demarcated lesion distribution corresponding to the sites of lime and sunlight supports a diagnosis of lime-induced phytophotodermatitis.
Pediatric lime-induced phytophotodermatitis is rarely reported in Japan, and to our knowledge, this is the first reported case of lime-induced phytophotodermatitis in a Japanese child. This may be because exposure to lime is uncommon among Japanese children and the diagnosis may not be readily considered in routine clinical practice. Phytophotodermatitis typically develops within 48 h after exposure to furocoumarins and sunlight []. In this case, skin lesions were noted 3 days after exposure to lime and sunlight. Such a delayed onset can obscure the causal relationship for patients, caregivers, and healthcare professionals alike, increasing the risk of misdiagnosis as contact dermatitis, infectious skin diseases, thermal burns, or child abuse []. Therefore, recognizing characteristic lesion morphology and obtaining a detailed history of recent exposure to furocoumarin-containing plants and sunlight are essential for an accurate diagnosis and differentiation from other dermatological conditions.
Statements
Data availability statement
The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author.
Ethics statement
According to the institutional ethics policy of the National Center for Child Health and Development, formal approval from the ethics committee is not required for case reports involving up to three patients, provided that written informed consent is obtained. In this case, written informed consent was obtained from the patient’s legal guardians for the use of clinical data and publication of this report, including the accompanying figure.
Author contributions
TY, RF, and KH managed the patient and collected clinical data. KY and TF supervised the case. TY drafted the manuscript. All authors contributed to the article and approved the submitted version.
Funding
The author(s) declared that financial support was not received for this work and/or its publication.
Conflict of interest
The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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The author(s) declared that generative AI was not used in the creation of this manuscript.
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References
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CarlsenKWeismannK. Phytophotodermatitis in 19 children admitted to hospital and their differential diagnoses: child abuse and Herpes simplex virus infection. J Am Acad Dermatol (2007) 57(5 Suppl. l):S88–91. 10.1016/j.jaad.2006.08.034
Summary
Keywords
contact dermatitis, furocoumarins, pediatric, phototoxicity, phytophotodermatitis
Citation
Yaguchi T, Fukuda R, Hashimoto K, Yoshida K and Fukuie T (2026) Pediatric lime-induced phytophotodermatitis in Japan: a case report. J. Cutan. Immunol. Allergy 9:17631. doi: 10.3389/jcia.2026.17631
Received
15 August 2026
Revised
08 October 2026
Accepted
13 October 2026
Published
28 October 2026
Volume
9 - 2026
Updates
Copyright
© 2026 Yaguchi, Fukuda, Hashimoto, Yoshida and Fukuie.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Tatsuki Fukuie, fukuie-t@ncchd.go.jp
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