Kelp Allergies

Kelp is an herbal supplement that is used to treat certain conditions. As with any herb used as a medication, there is a chance that you will develop an allergic reaction while taking it. Facial swelling, hives and shortness of breath may be signs of a severe allergic reaction that needs to be evaluated by a doctor. If you are diagnosed with an allergy to kelp, you must avoid ingesting it. Kelp is not a common food and is not difficult to avoid.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

What Is It?

Kelp, also known as bladderwrack, is a type of ocean seaweed that looks like a tree 1. Kelp comes in various colors, such as brown, green and red. The plant is commonly used medicinally for conditions such as thyroid disorders, arthritis, digestive disorders and iodine deficiency, according to MedlinePlus 1. It has also been used to promote a healthy immune system, although none of these claims have been evaluated by the Food and Drug Administration.

Allergic Reaction

You can develop an allergic reaction any time you introduce a new substance into your body. The first few times you take kelp, you many not experience any adverse reactions. During this time, the immune system is building a resistance to the herb and will eventually attack it. The immune system creates immunoglobulin E antibodies to fight off the kelp. When you ingest the herb, your immune system identifies it as a dangerous substance and releases these antibodies. The presence of these antibodies causes mast cells to create histamine, a chemical that triggers inflammation and irritation in soft tissues.


Symptoms from an allergic reaction to kelp can lead to symptoms in various places throughout your body, such as in your digestive system, respiratory system and in your skin, according to the University of Maryland Medical Center. Common digestive reactions include:

  • gas
  • abdominal cramping
  • diarrhea
  • nausea
  • vomiting
  • pain

You can develop swelling in your lungs, sinuses and throat shortly after taking kelp. This will cause sinus congestion, asthmatic symptoms, coughing and wheezing. Your skin can develop rashes, such as hives or eczema.

Testing and Treatment

Stop taking kelp supplements immediately if you develop any allergy symptoms and call your doctor. Your doctor may advise you to eliminate the supplement from your diet or may want to perform allergy tests to confirm the allergic reaction.

If you are diagnosed with a kelp allergy, the most effective treatment is to avoid eating foods that contain kelp, such as many foods in Asian cuisine. If you develop mild allergy symptoms, such as a runny nose, eye irritation or skin rashes, an oral antihistamine may help reduce the symptoms. A severe allergic reaction is treated with an injection of epinephrine, a prescribed medication. If you think you're having a severe allergic reaction, call 911.