How long does it typically take to get results from a patch test?

The typical timeframe to get results from a patch test is 24-28 hours. This period allows sufficient time for the body to show a reaction to the allergen that was applied to the skin. A patch test is used to determine whether an individual has an allergic reaction to a specific substance, often cosmetic ingredients or hair dyes.

After 24-28 hours, any allergic reaction, such as redness, swelling, or itching, can be evaluated accurately and helps practitioners make informed decisions about product use on a client's skin. Immediate results would not provide a proper assessment since reactions can take time to manifest. Similarly, waiting 48-72 hours is longer than necessary for most standard patch tests, which is why 24-28 hours is considered the optimal duration for observation. A one-week wait would be excessive for most patch tests and is not a standard practice.