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上一期病例問答答對者獲獎名單為：
隨波不逐流、楊、Hautarzt Wong、Dr.Pan Bo、吳建華、如果是李白
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上期題目回顧：
有獎病例問答：皰病？疥瘡？
病史摘要：
患兒，男性，4歲，因左掌瘙癢性緊張性大皰伴糜爛1周就診。皮疹特點如圖。
可能的診斷（單選）：
A、線狀IgA皮病；B、膿皰瘡；
C、疥瘡； D、接觸性皮炎
正確答案：C、疥瘡
各選項回答比例統計如下：
下文是該病例的報告。
病例研究：
疥瘡具有如下臨床特徵：包括經典的隧道、結節、以及厚的角化過度的結痂。水皰通常出現在嬰兒及兒童的掌蹠處，而真正的大皰是很罕見的。為了分辨這些，我們把「大皰性疥瘡」定義為，患者有超過5mm的大皰，直接鏡檢或組織學檢查證實具有蟎類、卵、或硬糞塊。通過使用 「疥瘡」，「大皰」和「起皰」關鍵詞搜索，我們於2001年7月檢索了MEDLINE 中自1966年1月1日之後出版的文獻，並選用了經顯微鏡證實的病例作為綜述進行討論。
病例報導
患兒，男性，4歲，體健，瘙癢1周伴左手掌處出現1 - 3cm緊張性大皰和糜爛（圖1）。仔細觀察發現，患處具有5 至7mm的隧道（圖2）。鑑別診斷包括疥瘡、急性過敏性接觸性皮炎、大皰性膿皰瘡、兒童慢性大皰性疾病、單純性大皰表皮鬆解症。隧道處直接鏡檢發現有疥蟎存在（圖3）。給予患者應用5％菊酯乳膏，皮損處完全治癒。
Fig 1. Tense bullae.
圖1. 緊張性大皰。
Fig 2. Burrow adjacent to erosion.
圖2. 腐爛處附近的遂道。
Fig 3. Gravid female mite.
圖3. 懷卵雌蟎。
文獻複習結果：
Table 1. Clinical, laboratory, histologic, immunologic, and treatment data of 19 patients with bullous scabies
表1. MEDLINE檢索入住的19例大皰性疥瘡患者的臨床、實驗室、組織學、免疫學和治療的數據
討論：
我們文獻複習發現19名患者都出現了瘙癢性大皰性皮疹。在臨床上需要與類天皰瘡、天皰瘡、節肢動物叮咬反應、急性接觸性皮炎、大皰性膿胞病及大皰性表皮鬆解症相鑑別。大皰性疥瘡的流行病學、組織學和免疫病理學結果與大皰性類天皰瘡相似。一半患者的年齡都超過了60歲。在15例活檢標本中，10例（佔67%）表現出表皮下裂隙伴有不同程度的浸潤，嗜酸性海綿樣水腫，或者二者皆有的特徵。在15例直接免疫螢光檢查中， 5名患者（佔36%）表現為線性C3或者伴有表皮真皮結合處不同的免疫球蛋白相沉積。在8名患者中，有2名（25%）患者血循環免疫球蛋白與基底膜帶結合。在19名患者中，有11名（58%）患者最初被誤診為大皰性類天皰瘡，並應用強的松進行治療。
目前，有幾種學說試圖來解釋大皰的形成機制，包括金黃色葡萄球菌的二重感染，疹反應以及蟎蟲分泌的溶解酶。沒有證據表明為並發大皰性膿皰瘡。所有患者臨床表現均為緊張性大皰。無活檢標本顯示角質層下裂隙，包括感染金黃色葡萄球菌的僅有患者。蟎蟲的疹反應不會表現為在蟎蟲生長相同部位的大皰，該部位的蟎蟲生長已在絕大病例中證實。
Veraldi等人認為，來自蟎的溶解性分泌物可能會改變大皰性類天皰瘡抗原，隨後產生皮膚基底膜帶抗體。這些抗體可能會激活補體並聚集炎症細胞，包括嗜酸性粒細胞以及隨後釋放可能導致表皮下裂隙的酶類。
Scabies has several characteristic presentations including the classic burrow, nodules, and thick hyperkeratotic crusts. Vesicles are frequently present on the palms and soles of infants and children, whereas true bullae are rare. To distinguish these, we arbitrarily defined 「bullous scabies」 as patients with bullae greater than 5 mm and mite, egg, or scybala confirmed on direct microscopy or histology. Using keywords 「scabies,」 「bullous,」 and 「blistering,」 we searched MEDLINE in July 2001 for articles published after January 1,1966 and indexed in MEDLINE as of July 21,2001. Only cases with microscopic confirmation were selected for review.
CASE REPORT
A healthy 4-year-old boy presented with a 1-week history of pruritic, tense, 1- to 3-cm bullae and erosions on the left palm (Fig 1). Closer examination revealed 5- to 7-mm burrows (Fig 2). Differential diagnosis included scabies, acute allergic contact dermatitis, bullous impetigo, chronic bullous disease of childhood, and epidermolysis bullosa simplex. Direct microscopy of a burrow revealed Sarcoptes scabiei (Fig 3). The patient responded to permethrin 5% cream with complete resolution.
DISCUSSION
In our review of the literature, all 19 cases presented with a pruritic bullous eruption. The clinical differential diagnosis includes pemphigoid, pemphigus, arthropod bite reaction, acute contact dermatitis, bullous impetigo, and epidermolysis bullosa. The epidemiologic, histologic, and immunopathologic findings of bullous scabies mimic bullous pemphigoid. More than half the patients were older than 60 years of age. Of 15 biopsy specimens, 10 (67%) featured a subepidermal split with variable infiltrate, eosinophilic spongiosis, or both. Of 15 direct immunofluorescence studies, 5 (36%) showed linear C3 alone or in combination with various immunoglobulins at the dermoepidermal junction. Of 8 patients, 2 (25%) had circulating IgG binding to the basement membrane zone. Of 19 patients, 11 (58%) were initially given a misdiagnosis of bullous pemphigoid and treated with prednisone.
There are several theories to explain the mechanism of bullae formation including superinfection with S aureus, id reaction, and secretion of lytic enzymes by the mite. There is no evidence to support concurrent bullous impetigo. All patients presented with tense bullae. None of the biopsy specimens revealed a subcorneal split, including the only patient who grew S aureus. An id reaction to the mite is unlikely as bullae occurred at the same location that mites were demonstrated in most cases.
Veraldi et al has proposed that lytic secretions from the mite could alter bullous pemphigoid antigen with subsequent production of antibasement membrane zone antibodies. These antibodies could activate complement with recruitment of inflammatory cells, including eosinophils and subsequent release of enzymes that would produce a subepidermal split.
本文出自：J AM ACAD DERMATOL
the American Academy of Dermatology, Inc.（2003）