Foxtail Grass Foreign Body in Domestic Animals

Renee DiPietro, CVT
Associate Veterinary Information Specialist
Pet Poison Helpline

We love spending time in the outdoors with our pets. Many people also have farm animals that live outside all the time. Although there are many hazards for our pets in the outdoors, we don’t usually think of grass as being a problem. One tiny little invader in the grass family may surprise you. Foxtail grass seed heads or awns, can cause a life threatening situation for pets and other domestic animals.

What is a Foxtail Awn?

A Foxtail awn is the sharp, barbed, seed head of a grassy plant or type of Wild Barley. Other common names for foxtail type grasses include Cheatgrass, Speargrass, Bromegrass and Needlegrass. The applied nomer “Foxtail” describes the bushy cluster of seed awns characteristic of these plants. The foxtail and its penchant for attachment to the fur of traveling or investigating animals is the plant’s inherent mechanism for propagation.

The plant is an introduced species not native to the United States. Origins of this plant include Europe, Asia, and Northern Africa.  Currently, in the United states it is most commonly found in the western states (especially Southern California) but increased groundcover plantings for bird hunting dogs and other landscaping applications has seen this plant’s introduction into areas of the Midwest, the east coast, and other parts of the country. Plantings in other parts of the world also occur making it hard to guarantee that any one region is foxtail grass free.

Why is exposure to Foxtail Awns dangerous to Animals?

Foxtail Awns pose a risk as an insidious and dangerous foreign body for domestic animals, most commonly dogs. Other species including cats, and farm animals. Virtually any animal that can move through these grasses is at risk.

When the grass is young with plump seed heads, it is benign and does not put animals at risk as they move through it or investigate within it. As the awns dry, they harden, shrink, and become a sharp miniscule object with great penetration potential. The fur/hair, especially that of long coated hunting/birding type dogs easily dislodges the foxtail clusters from the dried plant. Once attached to the hair the clusters can break apart and dissemination of the individual sharp, barbed, seed awns can occur.

The awns can then gain entry to dog’s internal physiology in a variety of ways. Awns caught in fur around the ears can migrate into the inner ear causing irritation, infection, significant pain, and even damage/rupture to the ear drum.  Symptoms of this type of exposure can include visual evidence of other awns around or in the ears. Pawing at the ears, vocalization, redness, and swelling can also be common signs. Gentle inspection of the ear may reveal a puncture hole where the seed head has penetrated the area.

The eyes are an easy access point for these dangerous seeds. Squinting, conjunctivitis, swelling, ocular ulceration or erosion, ocular discharge, and attempts by the pet to rub the area may all be present. A thorough eye exam performed by your veterinarian may reveal the invading seed. Location and careful removal of the awn, possibly as a surgical procedure may be necessary to limit ocular damage and awn migration.

The skin is commonly penetrated, and this can occur in a variety of anatomical sites. In between the toes is a very common puncture site. From dermal penetration, the awns can migrate to many locations in the body.

The nose/nasal passages are also a common access point and migration of the awn can result in sneezing, nose bleeds, infection, significant pain, and breathing difficulty due to inflammation/swelling of the upper respiratory tract.

In some cases, these awns can be inhaled into the lungs, and from there can migrate further in the thoracic cavity to cause an accumulation of pus in the lungs (Pyothorax). Symptoms with this type of awn migration can include difficulty breathing, coughing, fever, and lethargy.  Diagnostics may include chest x-rays, blood work, and chest tap. Treatment once diagnosis has been made, includes surgical removal of the awn, antibiotic, and anti-inflammatory medications and symptomatic and supportive therapy. Intensive care is often essential for a good outcome.

Air accumulation in inappropriate areas of the chest cavity (Pneumothorax) can also occur relative to inhalation, penetration, and migration of foxtail awns. Common symptoms include difficulty breathing, voice change, lethargy, and blue coloring to the mucus membranes. Diagnostics for this condition are like those for Pyothorax. Pneumothorax is an emergency and is a life- threatening condition. Intensive treatment pursuits such as with Pyothorax are often essential for a good outcome.

Inhaled foxtail awns often become infected with bacteria and various other respiratory flora. Subsequent migration to other areas of the body can initiate severe infection.

This means that a possible sequalae of chest cavity invasion by foxtail awns is migration through the to the abdomen, leading to infection of the abdominal lining or Peritonitis. Symptoms of peritonitis may be generalized including lethargy, fever, vomiting and diarrhea, tarry black stools, weakness, abdominal pain, unusual stance, fluid accumulation in the abdomen, and more.  Diagnostics may include blood work, radiographs, and abdominal tap. Peritonitis is a life-threatening condition with a generally poor prognosis.

Migration of seed awns to the spine can result in Discospondylitis. Symptoms for this bacterial or fungal condition of the vertebrae and associated intervertebral discs, can include general symptoms such as fever, lethargy, anorexia, weight loss, and more specific musculoskeletal symptoms including difficulty walking, lameness, and in severe cases paralysis. Diagnostics for this condition may include bloodwork, radiographs, CT scans, and spinal taps. This is a serious condition that can result in permanent damage to the spinal column.

In a nutshell, foxtail awns are dangerous whenever and wherever they are picked up by an animal. Very few parts of the body are immune to possible penetration, subsequent injury, and infection.

Diagnosis

Once penetration, ingestion, or inhalation has occurred, the tiny barbs on the awn’s surface promote forward motion and deeper migration of this foreign body invader.

Symptoms resulting from dermal penetration injury may be noticed more rapidly after initial exposure than inhalation or ingestion. The reason for this is that dermal penetration is painful, and the localized area becomes quickly inflamed. While symptoms may be quickly noticed, diagnosis may be delayed as the foxtail quickly burrows into the flesh and can be hard to locate especially when localized inflammation is prominent.

Draining tracts are another common feature of recent foxtail awn penetration.

A dog persistently licking or biting between the toes may be the first indication that you pet has this type of foreign body penetration has occurred. This is a huge red flag, especially in geographic areas were foxtail grass is common.

If diagnosed and located quickly, the penetrating foreign body can often be removed before it has a chance to migrate and cause more life threating damage and infection. The veterinarian can probe the suspected area or in some cases investigate surgically to remove the seed head. If this is done before significant forward progress of the offending seed has been made, treatment may be limited to removal of the awn, flushing, if needed repair of the area, and antibiotic and anti-inflammatory treatment.

Diagnosis of foxtail awn invasion can be very difficult with many diagnostic avenues including surgical exploration often exhausted before solid diagnosis is made.

Foxtail awn foreign bodies can and do cause fatalities in domestic animals/pets every year.

There can be an extended period between dermal penetration, and especially inhalation, or ingestion of the seed head before deep migration into body cavities occurs. Serious symptoms can develop months after exposure to the offending flora.

For this reason, it is essential that pets with multiple and varying symptoms of unknown explanation, in areas where foxtail grasses are endemic, be examined quickly to ensure they have not developed a Foxtail grass foreign body condition.

Prevention

Some measures can be taken to prevent Foxtail  Grass foreign body injury to your companion and farm animals.

Keeping areas that pets/animals have access to mowed short to prevent seed development is a good first step.

Avoiding any pet/animal access to areas known to have Foxtail grass growing is another effective measure.

You can also groom and examine your animals daily and remove any seed heads found. Close examination of areas of the body where any seed heads were located is also important.  Quick response and veterinary examination to any redness, pain, or swelling at skin level is recommended. Foxtail foreign body penetration is always an urgent situation.

This is truly a situation where an ounce of prevention is worth pounds of cure.