Can you get an allergic reaction to hair colour if the product does not touch skin?

It is possible to have an allergic reaction to hair dye even if it does not come in contact with the skin. This is because the chemicals in hair dye can be absorbed through the scalp and cause a reaction. Symptoms of an allergic reaction to hair dye can include:

Itching

Redness

Swelling

Blisters

Hives

Difficulty breathing

Anaphylaxis

If you experience any of these symptoms after using hair dye, it is important to see a doctor right away.