A grass awn is a sharp, bristle-like structure that protects the seed of certain grasses. While serving a natural function in the plant’s reproductive cycle, these dried structures pose a physical hazard to animals, particularly domestic pets. This material easily attaches to fur and penetrates soft tissue, leading to serious medical complications. Understanding the mechanics and common points of entry is important for pet owners, especially during warmer months.
Identifying the Grass Awn
Grass awns are the dried seed heads of invasive annual grasses that harden as the plant matures. They appear as tan, straw-colored, or light brown spikelets, often bushy, leading to the common name “foxtail.” These awns are prevalent in dry, overgrown areas like fields, hiking trails, and untrimmed parks across North America. Hazardous species include Foxtail barley, Cheatgrass, and Wild barley. The danger is highest from late spring through the end of summer when the grasses dry out and the awns become brittle and easily detached.
The Unique Structure That Causes Harm
The danger of a grass awn lies in its specialized, microscopic structure, designed for seed dispersal and self-burial. The awn is covered in stiff, backward-pointing barbs or silica hairs, functioning like a fish hook or arrow. This design ensures the awn can only move in one direction: forward, burrowing deeper into the tissue with every movement the animal makes.
The awn’s movement is also driven by its hygroscopic nature, meaning it reacts to moisture. When the dried awn encounters bodily fluids, like sweat or tears, it swells and contracts. This reversible twisting and untwisting motion acts as a mechanical force, ratcheting the barbed seed deeper into the soft tissue. This mechanism explains why an awn embedded in the body will not naturally work its way out.
Common Sites of Entry and Associated Symptoms
Grass awns can enter a pet’s body through any opening or area of thin skin, causing a range of specific symptoms depending on the location.
Paws
The paws are a frequent site of entry, especially between the toes where the thin webbing is easily pierced. An embedded awn often leads to persistent licking or chewing, sudden limping, and the development of a painful, non-healing lump or abscess.
Ears
Awns entering the external ear canal cause immediate distress. Owners typically observe sudden, violent head shaking, head tilting to one side, or intense scratching at the affected ear.
Nasal Passage
If inhaled, usually while sniffing the ground, an awn can lodge in the nasal passage, triggering paroxysmal fits of sneezing. Nasal discharge, sometimes bloody, and pawing at the face may also occur.
Eyes
When an awn gets under the eyelid, it causes significant discomfort and can quickly damage the delicate surface of the eye. Symptoms include excessive squinting, redness, and thick, watery discharge.
Skin
If the awn penetrates the skin elsewhere on the body, it may create a small puncture wound that seals over. This results in a localized swelling, a draining tract, or a sore that fails to heal despite treatment.
Management and Prevention Strategies
The most effective management strategy is a thorough inspection of a pet after any time spent in areas with tall, dry grasses. Owners should meticulously check the entire coat, focusing on the ears, armpits, and especially the spaces between the paw pads. Trimming the fur around the ears and between the toes can reduce the surface area available for awns to attach.
If a grass awn is loose on the fur, remove it gently with tweezers before it embeds. If an awn has already penetrated the skin, ear canal, or any other body orifice, attempting home removal is strongly advised against. Pulling on an embedded awn can cause it to break apart, leaving fragments that migrate deeper into the body, which can cause severe infection.
Prompt veterinary intervention is necessary for any suspected embedded awn, as they rarely exit on their own. Removal often requires specialized tools like an otoscope or rhinoscope, and may necessitate sedation or anesthesia. Avoiding high-risk areas, such as overgrown fields, and using protective gear like dog boots are the best preventative actions.