What Are the Signs of an Allergic Reaction to Dye?

Often, the signs of an allergic reaction to dye involve a person's skin. For example, a person may develop itching, hives, or a rash because of contact with a dye to which he is allergic. Sometimes, however, an allergic reaction develops because of a dye that is injected into the body, such as in the case of contrast dye used in diagnostic imaging. That type of dye can cause such serious reactions as difficulty breathing and changes in blood pressure and heart rate. Additionally, some people also suffer reactions after ingesting some types of food dye.

One of the signs of an allergic reaction to dye is hives. When dye comes into contact with the skin of an allergic person, it can cause raised, red bumps or welts to develop, which are referred to as hives. These hives may develop only on the part of the body that has been touched by the dye, or they could develop all over. Some people develop just a few hives in response to the allergen, while others develop them over their entire bodies. Additionally, hives can come and go until the allergic reaction is over.

A rash can also develop as a sign of an allergic reaction to dye. This differs from hives, as it may appear as a collection of bumps that are more uniform in size than hive bumps. The rash also is more likely to affect an isolated part of the body, especially the area the dye touched, rather than the entire body. Like hives, an allergic rash often causes redness and itching. Sometimes it may only amount to a cluster or area of raised bumps, but some allergic rashes also blister and ooze fluid — this type of rash may even appear to crust over.

Interestingly, some people are not allergic to dye that touches the skin but instead to dye that is injected into the body. For example, a doctor may inject a type of dye into a person's body as part of a diagnostic imaging process. Some people develop an allergic reaction to this type of dye, which can include such signs as nausea and vomiting, shortness of breath, and significantly lowered blood pressure. An individual with an allergic reaction to dye may also become flushed and feel dizzy, or even lose consciousness. This type of allergic reaction can prove life threatening and usually means a person needs swift emergency medical attention.

Some people also develop allergic reactions to food dye. For example, after consuming a food that contains a particular dye to which a person is allergic, the affected individual may develop hives or a rash, or even suffer from an upset stomach. An individual might also experience a temporary worsening of a chronic skin condition, such as eczema, because of this type of allergy. In a severe case, difficulty breathing, chest tightness, and facial and throat swelling can occur as well, and would require emergency medical treatment.