Pediatric lime-induced phytophotodermatitis in Japan: a case report

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.Phytophotodermatitis is a non-allergic contact dermatitis caused by exposure to furocoumarins, phototoxic agents found in certain plants, followed by exposure to sunlight (1)(2)(3)(4). Herein, we report a rare case of lime-induced phytophotodermatitis in a Japanese pediatric patient.A 7-year-old boy with a history of food allergy and atopic dermatitis presented to our department with a 1-month history of a hand eruption. Four days prior tobefore the onset of the skin lesion, he had squeezed limes., and three days before onset, he had bathed in seawater shortly thereafter 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 painErythematous lesions with small vesicles gradually extended from the dorsal aspects of both thumbs to the index fingers and subsequently spread to the dorsum of the hands and forearms (Figure 1b,1c).. No skin lesions were observed on other sunexposed areas or lime-exposed areas, including the face, neck, or lower extremities, or palms. There was no history of exposure to potential contact allergens, such as rubber 書式を変更: フォント : 12 pt 書式を変更: フォント : 12 pt 書式を変更: フォント : 12 pt products, before the onset of the lesions.At presentation, 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 left third and fourth fingers (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 photoprotection measures, and the skin lesions resolved without residual pigmentation 4 months after onset.the clinical course was favorable.,Phytophotodermatitis which is primarily a clinical diagnosis and that generally does not require additional examinations such as phototesting or photopatch testing (1).The absence of lesions at sites exposed to sunlight alone or to 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 limeinduced phytophotodermatitisThe sharply demarcated lesion distribution corresponding to the sites of direct lime contact supports the involvement of lime rather than generalized photosensitivity. The patient was advised to apply emollients and practice photoprotection measures, and the clinical course was favorable.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 possibly because lime exposure is uncommon among Japanese children and the diagnosis may not be readily considered in routine clinical practice. Phytophotodermatitis typically develops within 48 hours after exposure to furocoumarins and sunlight (1). In this case, skin lesions were noted 3 days after exposure to lime and sunlight. In addition, the delayed onset of skin lesions several days after exposure Such a delayed onset can obscure the causal relationship for patients, caregivers, and healthcare professionals, increasing the risk of misdiagnosis as contact dermatitis, infectious skin diseases, thermal burns, or child abuse (5). Recognizing characteristic lesion morphology and obtaining a detailed history regarding recent exposure to furocoumarin-containing plants and sunlight are therefore essential for accurate diagnosis and differentiation from other dermatologic conditions.書式を変更: フォント : 12 pt 書式を変更: 蛍光ペン (なし) Well-demarcated pigmentation extending from the dorsal aspects of both thumbs to the index fingers, with confluent pigmentation also observed on the left third and fourth fingers.