What symptom would indicate an allergic reaction to a tattoo procedure?

An allergic reaction to a tattoo procedure often manifests as localized symptoms, particularly at the site of the tattoo. Redness and a rash around the tattoo site are common indicators of an allergic response to the inks or materials used during the process. This localized reaction can appear as swelling, itchiness, or a rash, which are typical responses of the body's immune system when it identifies a substance as a potential irritant or allergen.

In contrast, symptoms like nausea and vomiting may indicate a systemic reaction but are not specifically tied to local allergic responses related to tattoos. Cold hands and feet are more indicative of circulatory issues or shock rather than an allergic reaction. Similarly, an increased heart rate can occur due to various factors including anxiety or pain but does not directly signal an allergic response at the site of the tattoo. Therefore, redness and rash around the tattoo site is the most specific symptom indicating an allergic reaction in the context of tattooing.