Conditions that are related to ragweed allergy include:

• Allergic rhinitis (hay fever). An inflammation of the mucous membranes that line the nose due to an allergic reaction to pollen, dust or other airborne substances. People with hay fever are at increased risk of developing other respiratory conditions because their allergy causes them to frequently breathe through their mouths. The nasal passages are lined with tiny hair–like structures called cilia that act like filters, preventing harmful particles from entering the body. When people breathe through their mouths, these filters are bypassed and particles can proceed directly to the lower respiratory system (e.g., lungs).
  

  

• Chronic rhinosinusitis. A chronic infection of the sinus cavities. The signs and symptoms of chronic rhinosinusitis include a yellow-green mucus discharge and chronic cough.
  
  

  

• Allergic rhinosinusitis. An allergy-triggered inflammation and infection of the mucous membranes lining the paranasal sinuses.
  
  
• Allergic bronchitis. An allergic inflammation in the lower airway of the respiratory system. It is a type of asthma, an inflammatory condition of the airways.
  
  

  

• Allergic conjunctivitis. An allergic inflammation of the tissues lining the inside of the eyelid.
  

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Ragweed is a member of the plant family known as Compositae. It is one of the largest plant families and includes almost 20,000 different species including the daisy, artichoke, echinacea and dandelion. Plants are characterized according to family based on common features and similarities in structure. Families of plants will include a wide variety of plants that do not, on casual examination, look similar but share important characteristics that make them scientifically comparable. Plants that are members of the same family can create similar allergic reactions in an individual, a phenomenon known as cross-reactivity.

Oral allergy syndrome is a type of cross-reactivity in people highly sensitive to particular pollens. Ragweed allergy may induce oral allergy syndrome. During the seasons that ragweed pollinates, the patient may experience a rapid onset of itching in the mouth and throat after attempting to eat foods from the same plant family. The symptoms of this allergy will usually resolve quickly after the food is removed from the mouth.

Ragweed allergy sufferers may experience oral allergy syndrome to other members of the plant family, including the following plants:

• Cantaloupe
• Watermelon
• Honeydew melon
• Banana
• Chamomile
• Mugwort
• Sunflowers
• Dandelion
• Goldenrod

In addition, people with ragweed allergies should avoid using de-lousing products. The chemicals in these products may cause a cross-reaction in people with a ragweed allergy.

Allergic cross-reactions can range from mild to the severe systemic allergic reaction anaphylaxis, which can cause breathing difficulties and even death. It is important to know what plant family is associated with a person’s hay fever in order to ensure that proper precautions are taken to avoid all contact with ragweed allergens.