We strive to provide personalized medical care.

Contact dermatitis and Patch test

What is contact dermatitis?

Contact dermatitis occurs when the skin becomes hypersensitive to the material you touch and it can even develop inflammation. For some materials, anybody who comes into contact with them develops dermatitis. Allergic dermatitis occurs only when the person is allergic to the contact material.

Materials that could induce contact dermatitis

Cosmetics in general, Metals (accessories, buckles, dental inlays…etc.), Ointment (prescribed ointment as well), Foods and plants (mango, flowers, green plants…etc.), Latex, Leathers, Clothes (chemicals used for cleaning), UV …etc. i.e. anything that we encounter on a daily basis could be the cause of the contact dermatitis.

  • As for cosmetics, you may have been using the pertinent cosmetics for years without any troubles. But the allergic reaction could take years to develop. Please be aware that there are no cosmetics that never cause allergies.

Patch test

To identify the cause of the contact dermatitis, we do a patch test. When you know the cause of your dermatitis, you can avoid or remove the material from the environment around you. When we do the patch test using the skin on your back, it should be in winter when you do not sweat. Usually this season is from November to March in the Tokyo area.

Actual test procedure

  1. We use the skin of your back. Patches are prepared by applying the suspected material in advance. The patches are then placed on the skin. Adhesive tapes are applied on top of the patches so that they do not move. We can check up to 14 materials at one time.
  2. You have to return 2 days later so we can remove the patches and then assess the reaction of your skin.
  3. A final assessment is done on the third day.


  • The patch test requires an appointment. Please call us during business hours.
  • For metal allergies we can test Nickle, Cobalt, Gold, Platinum, …etc. There are 13 in total, but this test doesn’t include Titanium.
  • You cannot take a bath during the test period, which is 3 days. You can rinse your body by taking a shower but refrain from washing the skin area where the test is being done.
  • You also shouldn’t do exercise or other things that induce sweat during the test period.