Which of the following are signs of an allergic reaction during a barber service?

The signs of an allergic reaction during a barber service typically include redness, itching, and swelling. These symptoms are physical responses of the body to a foreign substance or allergen, such as certain chemicals found in hair dyes, shampoos, or other hair care products. When an individual is allergic to an ingredient, their immune system reacts by causing inflammation, which manifests as redness and swelling in the affected area. Itching is also a common symptom, as the body's response can lead to irritation of the skin.

In contrast, symptoms or conditions like hair loss and dandruff, dry skin and split ends, or excessive shine and greasiness do not typically align with the immediate immune response related to allergies. These issues could be caused by a variety of other factors such as product buildup, environmental conditions, or hair health rather than an allergic reaction.