Spirulina is a blue-green algae that has been used for cooking for centuries and is used as a dietary supplement in recent times, according to the Drugs.com website. An allergy to spirulina is unlikely, but possible. The food-supplement has not been adequately studied by the Federal Drug Administration and should not be used to treat any condition without your doctor's consent. If you develop adverse reactions after you consume spirulina, you should talk with your doctor for an accurate diagnosis and treatment recommendations. Discontinue using spirulina until you can be seen by your doctor.

Immune System Reaction

If you have a genuine allergy to spirulina, your immune system plays a vital role in the development of symptoms. The American Academy of Allergy, Asthma and Immunology states that when you ingest the allergen, your immune system identifies the otherwise safe food as harmful and begins to attack it. The immune system creates immunoglobulin E, or IgE antibodies that are released into the blood stream. IgE antibodies cause mast cells in the body to produce histamine, a chemical that leads to inflammation in soft tissue.

Symptoms

Depending on the severity of the allergy, you may develop various symptoms in different degrees. You may develop mild to severe symptoms within a few minutes after consuming spirulina. Common symptoms related to a food allergy, include diarrhea, abdominal pain, itching, difficulty swallowing, nasal congestion, nausea, runny nose, lightheadedness, swelling, vomiting, stomach cramps and shortness of breath, according to MedlinePlus. You may also develop hives or eczema as a result of an allergic reaction.

Testing

Because an allergy to spirulina is uncommon, you doctor may want you to participate in various tests to determine the exact cause of the symptoms. The MedlinePlus.com website states that blood tests and skin-prick tests are common ways to diagnose allergies. A blood test uses a sample of your blood. The suspected allergen, spirulina is added to your blood to see if your blood creates IgE antibodies. If it does, you are allergic to the substance. Skin-prick tests expose a small amount of the allergen under the skin to see if an adverse reaction develops.

Consideration

Not all symptoms that develop after ingesting spirulina are related to an allergy. Other symptoms may be a sign of another condition or an intolerance toward spirulina. If you test positive for an allergy to spirulina, you may be advised by your doctor to avoid other algae.