Equine Clinic: Surgery and Radiology, Freie Universität Berlin, Berlin, Germany.
Small Animal Clinic, Freie Universität Berlin, Berlin, Germany.
BMC Vet Res. 2022 Feb 26;18(1):80. doi: 10.1186/s12917-022-03162-2.
Primary photosensitization rarely occurs in horses and can easily be misinterpreted. Descriptions of the disease in horses after ingestion of parsnip are lacking. The aim of this case series was to describe the dermatological and ocular changes due to photosensitization and to raise awareness of parsnip being a possible aetiologic agent.
Nine horses from three different stables in Berlin and Brandenburg, Germany, presented variable degrees of erythema, scaling, crusting and necrosis of unpigmented skin at the head and prepuce. Horses were of different breeds with a median age of 15 ± 5.9 years. A mild leukocytosis was diagnosed in 1/9 horses at admission. Analyzed liver enzymes were within the reference ranges in all horses. Ocular changes were diagnosed as follows: blepharitis (3/9), conjunctivitis (7/9), corneal edema without additional signs of keratitis and/or uveitis (2/9), corneal edema with signs of uveitis (1/9) and photophobia (4/9). One horse developed a fluorescein positive corneal erosion. Skin biopsy (1/9) revealed a moderate to severe acute, eosinophilic and lymphocytic dermatitis with dermal edema and vasculitis. All stables housing these patients fed hay from the same distributer. Analyzed hay samples showed high contents of wild parsnip (plants, seeds, roots). Wild parsnip is widespread in Europe and contains furocoumarins, a family of photodynamic pigments, which may cause primary photodermatitis, keratoconjunctivitis and uveitis. Horses were treated according to severity of clinical symptoms systemically with flunixine meglumine (1.1 mg/kg BW 1-2x/day) or prednisolone (1 mg/kg BW 1x/day). Topically, either gentamicin (3x/day), dexamethasone (2-3x/day) and/or atropine (1x/day) were used. Skin care was provided with almond oil or dexpanthenol (2x/day). All horses were kept in a dark environment or were treated with sunscreen and facemasks. Duration of treatment varied from 6-30 days (median 11.3 days).
Ingestion of wild parsnip (Pastinaca sativa) can induce primary photosensitization with dermatitis and ocular injury in horses. In times of extreme weather, hay may alter in botanical composition, resulting in high amounts of uncharacteristic plants causing novel problems.
原发性光敏作用在马中很少见，很容易被误诊。关于马摄食欧洲防风草后发生该病的描述较少。本病例系列的目的是描述因光敏作用引起的皮肤和眼部变化，并提高对欧洲防风草可能是病因的认识。
来自德国柏林和勃兰登堡州三个不同马厩的 9 匹马表现出头颈部和包皮无色素皮肤不同程度的红斑、鳞屑、结痂和坏死。这些马的品种不同，中位年龄为 15±5.9 岁。入院时，1/9 的马被诊断出轻度白细胞增多。所有马的分析肝酶均在参考范围内。眼部变化诊断如下：结膜炎（3/9）、结膜炎（7/9）、角膜水肿无其他角膜炎和/或虹膜炎迹象（2/9）、角膜水肿伴虹膜炎迹象（1/9）和畏光（4/9）。1 匹马出现了荧光素阳性角膜糜烂。皮肤活检（1/9）显示中度至重度急性、嗜酸性和淋巴细胞性皮炎，伴有真皮水肿和血管炎。所有饲养这些马匹的马厩均从同一家分销商处喂食干草。分析的干草样本显示，野生欧洲防风草（植物、种子、根）含量很高。野生欧洲防风草在欧洲广泛分布，含有呋喃香豆素，这是一类光动力色素，可能引起原发性光皮炎、角结膜炎和虹膜炎。根据临床症状的严重程度，马匹全身系统地接受氟尼辛甲胺（1.1mg/kg BW 1-2 次/天）或泼尼松龙（1mg/kg BW 1 次/天）治疗。局部使用庆大霉素（3 次/天）、地塞米松（2-3 次/天）和/或阿托品（1 次/天）。使用杏仁油或泛醇（2 次/天）进行皮肤护理。所有马匹均被置于黑暗环境中或接受防晒霜和面罩治疗。治疗持续时间从 6 天至 30 天不等（中位数为 11.3 天）。
摄食野生欧洲防风草（Pastinaca sativa）可引起马的原发性光敏作用，导致皮炎和眼部损伤。在极端天气条件下，干草的植物成分可能会发生变化，导致大量不典型植物出现，引发新的问题。
