Oklahoma Cosmetology Board Practice Exam

Which of the following is a common sign of an allergic reaction to hair dye?

1. Itching and irritation of the skin

2. Redness and swelling of the scalp

3. Dryness and flaking of hair

4. Increased hair fall

The correct answer is: Redness and swelling of the scalp

A common sign of an allergic reaction to hair dye is redness and swelling of the scalp. This occurs as the body's immune system responds to a substance in the hair dye that it perceives as harmful. The scalp, being highly sensitive, can exhibit these symptoms prominently, leading to inflammation in that area. Itching and irritation of the skin can also occur, but they are more generalized symptoms and may not be exclusive to allergic reactions. Dryness and flaking of hair or increased hair fall are usually associated with other conditions, such as improper hair care or exposure to harsh chemicals, rather than a direct allergic reaction to hair dye. Thus, the specific redness and swelling signal a localized inflammatory response typical of an allergy.