What is Pigweed Allergy? – Symptoms, Causes, and treatment

Overview of Pigweed Allergy

Pigweed Allergy, also known as Lamb’s Quarters. It is a weed that produces heavy pollen and can cause asthma, conjunctivitis symptoms, and hay fever. During the summer months, pigweed pollen is most common.

Pigweed is an annual herb. It usually grows throughout the world including, locales such as Europe, the United States, Brazil, Korea, Spain, Mozambique, Mexico, Hungary, Germany, Afghanistan, Africa, etc in recently disturbed soil and agricultural fields. It can be found in crops, roadsides, nurseries, and other rural areas.

The plant grows to 10 feet tall. The leaves are dull green in color at the top of the plant. The flowers are close-packed and sometimes showy. Pollen shed and flowering occur at the same time.

The pollen grains look the same to observers conducting pollen counts through their microscopes. Common names for these plants are also used mutually depending on where you are in the country. Usually, the peak time for the sparse pollen shed is Late summer to autumn.

Symptoms of Pigweed Allergy

The Pigweed family ( Amaranthaceae ) includes many subfamilies (palmer amaranth, Amaranthus retroflexus) and over 500 species, including Common Pigweed, Prostrate Pigweed, Powell Amaranth, and Tumble Pigweed, the most common of these being Common Pigweed.

These are annual plants that grow from seeds from late winter through summer. Common pigweed allergy symptoms can be similar to many other grass pollen allergies. The symptoms include:

  • Sneezing
  • Runny nose
  • Nasal congestion
  • Itchy throat and eyes
  • Watery eyes
  • Wheezing
  • Hay Fever (allergic rhinitis)
  • Cough
  • Blocked sinuses
  • Extreme tiredness

If you’re allergic to common pigweed and have asthma, the weed pollen may trigger or worsen allergic asthma symptoms, such as coughing and wheezing.

Amaranthus retroflexus or redroot pigweed is a specie of flowering plant that cause pigweed allergy.

How is pigweed allergy diagnosed?

Your doctor can usually diagnose a pigweed allergy. However, they may you refer to an allergist (an allergy specialist) for allergy testing to confirm the diagnosis. Someone, who specializes in diagnosing and treating allergies is called Allergist.

The allergist will first ask you about your symptoms and medical history. Make sure to tell your allergist if the symptoms are always present or at certain times of the year. Your allergist will perform a skin prick test (SPT) or specific IgE blood test to find out the specific allergen that is causing your symptoms.

During this test, the allergist will insert a small number of different types of allergens after pricking different areas of the skin. Within 15 to 20 minutes, if you have an allergic reaction to any of the substances you will develop swelling, redness, and itchiness at the site. Your allergist may also perform a blood test. In this test, your allergist will take a blood sample and send it to the laboratory


As with other allergies, avoidance of relevant allergens is the best treatment. However, it is very difficult to avoid them because they are everywhere. In severe allergy reactions, allergy shots are given to eliminate the presence of allergy. You can take allergy shots at home after the permission of your allergist. Check your allergy shots dosage chart or schedule here. You can minimize your exposure to pollen by:

  • Wear a pollen mask whenever you go outside
  • Limit time outside when pollen counts are high and check local pollen counts daily
  • The best time to go outside is after a good rain because rain helps to clear pollen
  • Keep the window closed during high pollen count
  • Wash bedding at least twice a week in hot and soapy water
  • Dry all clothes in a dryer instead of drying them outside
  • Use certified asthma and allergy air filters.
Young woman undergoing allergen skin prick test in clinic for the diagnosis of Pigweed allergy.

Frequently asked questions / FAQs

Can I be allergic to pigweed?

As pigweed allergy symptoms are similar to other pollen allergies, therefore, you will be allergic to it if you have any allergic reaction to pollens. The common symptoms are Sneezing, Runny nose, Nasal congestion, Itchy throat, and eyes
Watery eyes, Wheezing, Hay Fever, Cough.

Foods related to Pigweed

Common foods related to common pigweed include hazelnut, melon, watermelon, persimmon, banana, tomato, citrus, pineapple, zucchini, peanut, and many more.

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