Which of the following is NOT a symptom of scalp irritation?

Thinning hair is not typically regarded as a symptom of scalp irritation. While scalp irritation can manifest through immediate physical reactions such as itching, swelling, and excessive flaking of the skin, thinning hair is generally a longer-term concern that may result from a variety of factors, including genetics, hormonal changes, and overall health rather than direct irritation of the scalp.

Scalp irritation commonly presents with more acute symptoms that indicate inflammation or an adverse reaction, such as redness, itching sensations, and flaking skin which can be quite evident. Thinning hair, however, might occur as a result of ongoing conditions or practices affecting hair growth and health rather than being a direct symptom of irritation at that moment. Therefore, focusing on the nature of scalp irritation helps clarify why thinning hair does not fit within that context.