Patch test

Japanese: パッチテスト

This is an important method for determining the cause of contact dermatitis by testing for allergies to chemical substances, cosmetics, medicines, etc. by applying the substance to the back or upper arm. Patch tests are also used to search for factors that worsen chronic eczema, atopic dermatitis, and hand eczema, as well as to test for allergies to oral medications and dental metals.

In fact, substances suspected to cause contact dermatitis or drug allergies are removed for 48 hours. Paste ( Chofu ) After 24 hours, the area becomes red and swollen ( Erythema ( Kohan ) and edema ( Fushu ) ), or bumps ( Papule ( Emergency ) If a positive result is detected, the test is considered positive. Do not wet the area where the patch test was performed (such as your back) by bathing or other means until the result is determined.

Allergic reactions to unexpected substances that you are exposed to unknowingly in your daily life can be related to the onset or worsening of dermatitis, so it is important to consult with a dermatologist prior to the test about which substances will be used for the patch test.

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

Japanese:

　化学物質、化粧品や薬剤などに対するアレルギーの有無を、それらの物質を背中や上腕に貼って調べる検査で、接触皮膚炎の原因を決めるのに重要な方法です。また慢性湿疹やアトピー性皮膚炎、手湿疹の悪化因子の検索のほか、内服している薬剤や歯科金属によるアレルギーの検査にも、パッチテストを行います。

　実際には、接触皮膚炎や薬剤アレルギーの原因として疑われる物質を48時間貼付(ちょうふ)し、その24時間後にその部位が赤くなってはれる（紅斑(こうはん)および浮腫(ふしゅ)）、またはぶつぶつ（丘疹(きゅうしん)）ができたら陽性と判定します。判定が終わるまでは、パッチテストを行っている部位（背中など）を入浴などで濡らしてはいけません。