Paller A S, Eramo L R, Farrell E E, Millard D D, Honig P J, Cunningham B B
Department of Pediatrics, Northwestern University Medical School, Chicago, Illinois, USA.
Pediatrics. 1997 Sep;100(3 Pt 1):360-4. doi: 10.1542/peds.100.3.360.
Blue light phototherapy is commonly administered to neonates as treatment of indirect hyperbilirubinemia, often in conjunction with blood transfusions to treat hemolytic anemia. We observed a distinctive cutaneous complication of phototherapy in six neonates with hyperbilirubinemia.
We studied the clinical and histologic characteristics of the eruption, as well as the porphyrin levels in affected neonates. Five of the patients had erythroblastosis fetalis; the other had profound anemia from twin-twin transfusion. All of the neonates developed purpuric patches at sites of maximal exposure to the phototherapy lights, with dramatic sparing at shielded sites within 24 hours after initiation of the phototherapy. On discontinuation of phototherapy, all eruptions cleared within 1 week. Examination of skin biopsy sections showed purpura without significant inflammation or keratinocyte necrosis. Plasma porphyrins (copro- and proto-) were elevated in the two patients in which they were assessed.
The distribution of the eruption in areas exposed to light and presence of circulating porphyrins suggest that porphyrinemia may underlie the light-induced purpuric eruption. Additional studies will be required to determine definitively the mechanisms of both the purpuric phototherapy-induced eruption and the development of increased blood porphyrin levels in these transfused neonates.
蓝光光疗常用于新生儿间接高胆红素血症的治疗，常与输血联合用于治疗溶血性贫血。我们在6例高胆红素血症新生儿中观察到一种独特的光疗皮肤并发症。
我们研究了皮疹的临床和组织学特征，以及受影响新生儿的卟啉水平。5例患者患有胎儿成红细胞增多症；另一例因双胎输血导致严重贫血。所有新生儿在光疗灯最大照射部位出现紫癜斑，在开始光疗后24小时内，受保护部位明显 spared。停止光疗后，所有皮疹在1周内消退。皮肤活检切片检查显示紫癜，无明显炎症或角质形成细胞坏死。在评估的2例患者中，血浆卟啉（粪卟啉和原卟啉）升高。
皮疹在光照部位的分布以及循环卟啉的存在表明，卟啉血症可能是光诱导紫癜性皮疹的基础。需要进一步研究以明确光疗诱导紫癜性皮疹的机制以及这些输血新生儿血卟啉水平升高的原因。
