Eczema

• Sensitivity to red dye sometimes manifests itself as eczema, which is an itchy rash that can appear anywhere on the body. Affected areas may be dry, flaky, and inflamed. An oozing crust, which may look like a lesion, can sometimes to develop in younger children.
  
  

Respiratory Problems

• A mild reaction to red dye may affect breathing by causing an individual to become congested. However, it is also possible for a severe reaction to cause the throat to swell and prevent breathing altogether.
  
  

Gastrointestinal Problems

• When red dye is ingested by a sensitive individual, they may experience varying levels of gastrointestinal discomfort. Vomiting, diarrhea, gas and cramps are all common symptoms when an allergen is eaten.
  
  

Emotional Problems

• Allergic reactions can sometimes impact an individual's mental state. They may feel anxious, restless or dizzy. Some speculate that red dye exacerbates ADHD, ADD, hyperactivity and moodiness in children. In children diagnosed with emotional or mental disorders, the removal of red dye from their diet has been known to significantly improve their daily performance.
  
  

Hives

• Hives are a common symptom of an allergic reaction. These itchy red welts appear in clusters anywhere on the body, but usually respond well to an antihistamine. Hives are more likely to occur if a sensitive individual applies red dye directly to their skin.
  
  

Angioedema

• Angioedema, or swelling, is another symptom that can indicate an allergic reaction. The areas that are most commonly affected are the face, eyelids, tongue and lips. Although angiodema is not commonly associated with red dye sensitivity, this sort of reaction is certainly a possibility and should be monitored closely.
  
  

Anaphylatic Shock

• Anaphylactic shock is the most severe allergic reaction that an individual can have. When the body encounters an allergen, it releases a flood of chemicals called histamines that cause unpleasant symptoms. If enough histamines are released, an individual may go into shock. This warrants an immediate trip to the emergency room. There are only a few documented cases of red dye causing anaphylaxis.