Fifth disease - 五番目の病気
五番目の病気 (Fifth disease) 16か月 ― 両頬が叩かれたように赤くなり、全身に斑状丘疹状の発疹が現れます。
両頬に紅斑。
relevance score : -100.0%
References伝染性紅斑（Fifth disease）は、ヒトパルボウイルス B19 によって引き起こされるウイルス感染症です。小児に多く見られ、主に 4 歳から 14 歳の間で罹患します。症状は多くの場合、軽度の発熱、頭痛、喉の痛み、インフルエンザ様の不快感から始まります。子どもは顔に slapped cheeks（打撲様頬）に似たはっきりとした赤い発疹が現れ、体や腕、脚にも斑状の発疹が出ることがあります。成人では関節痛が一般的な症状で、感染から数週間後に出現することもあります。特に、パルボウイルス B19 に感染した成人の約 20～30％は無症状である可能性があります。
Fifth disease (erythema infectiosum) is a viral infection caused by human parvovirus B19. It is more common in children than adults and usually affects children ages 4 to 14. The disease often starts with mild fever, headache, sore throat, and other flu-like symptoms. Children can also develop a bright red rash on the face that looks like “slapped cheeks”, along with a lacy or bumpy rash on the body, arms, and legs. In adults, joint aches are a common symptom. Rash and joint symptoms may develop several weeks after infection. About 20 to 30% of adults who are infected with parvovirus B19 will not have symptoms.
Fifth disease (erythema infectiosum) is a viral infection caused by human parvovirus B19. It is more common in children than adults and usually affects children ages 4 to 14. The disease often starts with mild fever, headache, sore throat, and other flu-like symptoms. Children can also develop a bright red rash on the face that looks like “slapped cheeks”, along with a lacy or bumpy rash on the body, arms, and legs. In adults, joint aches are a common symptom. Rash and joint symptoms may develop several weeks after infection. About 20 to 30% of adults who are infected with parvovirus B19 will not have symptoms.
Parvovirus B19 が母親から赤ちゃんへ感染するリスクは約 33% で、感染した女性の約 3% が赤ちゃんに合併症を経験します。妊娠 20 週前に母親が感染すると、血液疾患や胎児の体液貯留などの合併症が起こりやすくなります。この病気の管理を開始するには、特定の抗体（IgM）を検査し、患者がパルボウイルスに曝露されたかどうかを確認する必要があります。検査で過去の曝露がなく、最近の感染が示された場合、妊娠中は赤ちゃんの健康状態をチェックするために、定期的な超音波スキャンなどの綿密なモニタリングが必要です。
The rate of vertical transmission during maternal parvovirus B19 infection is estimated at 33%, with fetal complications occurring in 3% of infected women. Fetal complications comprising hemolysis, anemia, and nonimmune hydrops fetalis and fetal loss are more frequent when maternal infection occurs before 20 weeks of gestation. The first step in the management of this patient would be to obtain immunoglobulin (Ig) M and IgG titres against parvovirus to evaluate if the patient has had previous immunity against the disease. If results are negative for IgG but positive for IgM (ie, primary infection), this patient would need close obstetrical monitoring for the following weeks, including serial ultrasounds to rule out fetal anemia and hydrops fetalis.
The rate of vertical transmission during maternal parvovirus B19 infection is estimated at 33%, with fetal complications occurring in 3% of infected women. Fetal complications comprising hemolysis, anemia, and nonimmune hydrops fetalis and fetal loss are more frequent when maternal infection occurs before 20 weeks of gestation. The first step in the management of this patient would be to obtain immunoglobulin (Ig) M and IgG titres against parvovirus to evaluate if the patient has had previous immunity against the disease. If results are negative for IgG but positive for IgM (ie, primary infection), this patient would need close obstetrical monitoring for the following weeks, including serial ultrasounds to rule out fetal anemia and hydrops fetalis.
五番目の病気 (fifth disease) は、微熱、頭痛、発疹、鼻水や鼻づまりなどの風邪様症状から始まります。これらの症状が消えた数日後に発疹が現れます。真っ赤な発疹は顔、特に頬に最も顕著に出ます（そのため「頬を叩く病気」という名前が付けられました）。頬の赤みとともに、子供は体の他の部位にも赤いレース状の発疹が現れることが多く、上腕、胴体、脚が主な出現部位です。
通常は軽症ですが、妊娠中の女性が妊娠第1期に感染すると、胎児水腫や自然流産のリスクが高まります。
○ 処理
時間の経過とともに自然に改善するため、特別な治療は必要ありません。