Grass seeds: a summer menace

A small, harmless-looking grass, the grass seed (or grass awn) — known in France as « voyageur » or, in the south, « spigaou » — is a formidable trap for dogs in summer. From May to October, vet practices see dogs every day with an ear infection and a tilted head, a wound between the toes, or violent sneezing with a nosebleed. Behind these symptoms, the culprit is almost always the same: a grass seed lodged somewhere in the body. Worse still, its harpoon shape makes it work its way ever deeper into the tissues, sometimes far enough to puncture a lung or a bladder. Here is how to recognise it, avoid it and remove it in time.

What is a grass seed and why is it dangerous?

The grass seed is the fruit (or "inflorescence") of several wild grasses: Hordeum murinum (wall barley), Avena fatua (wild oat), Bromus, Aegilops. It measures 1 to 3 cm and has a particular structure:

• A sharp point that pierces the skin or mucous membranes.
• Backward-facing barbs that stop it from backing out.
• A one-way mechanism: every muscle movement or tissue contraction pushes the seed forward, never back.

Once in, it will never come out on its own. It can migrate tens of centimetres through the tissues, puncture organs, create fistulas and cause serious infections.

The 6 most affected areas and their symptoms

1. Ears (ear canal) — the no. 1 location:

• Head suddenly tilted to one side.
• Violent head shaking, frantic scratching at the ear.
• Whining or yelping when the ear is touched.
• Risk of a perforated eardrum within hours, middle or inner ear infection, balance problems.

2. Nose / nasal cavity:

• Sudden, repeated sneezing, sometimes in explosive bursts.
• Nosebleed (epistaxis) from one nostril.
• The dog rubs its nose with its paws.
• Risk of migration to the sinuses, or even the brain.

3. Between the toes (interdigital spaces):

• Compulsive licking of one paw.
• Limping, pain when putting weight on the foot.
• A small round wound with swelling, sometimes a draining fistula after a few days.
• Possible migration under the skin, deep abscess.

4. Eye (under the third eyelid):

• Half-closed eye, watering, swollen eyelid.
• The dog rubs its eye.
• Risk of corneal ulcer, or even perforation.

5. Under the skin (flank, belly, armpits):

• A small lump under the skin, sometimes a chronic fistula.
• Unexplained limping.
• Possible migration to the lungs, mediastinum or abdomen.

6. Genital / urinary tract (vulva, prepuce):

• Intense licking of the genitals.
• Cystitis, blood in the urine.

A special case: deadly migration

In the most serious cases, the grass seed does not stay put. It can travel along remarkable paths:

• From the nose to the sinuses and then the brain (fatal meningoencephalitis).
• From the skin into the chest cavity through the connective tissue (pleurisy, lung abscess).
• From the mouth to the mediastinum (mediastinitis, guarded prognosis).
• From between the toes up the leg and into the joint (septic arthritis).

These cases account for a few % of consultations but often have a poor prognosis because they are diagnosed late. Unexplained chronic lameness after the summer in a hunting dog should always raise the possibility of a migrating grass seed.

What to do if you suspect a grass seed

IF the seed is visible and within reach (just caught in the coat, not yet embedded):

• Use tweezers and grip the seed by its outermost end.
• Pull gently and steadily in the direction it went in.
• Disinfect the area with chlorhexidine or diluted povidone-iodine (Betadine).
• Keep an eye on the area over the next few days to check no fragment was left behind.

IF the seed has already gone in (ear, nostril, under the skin, under the eye):

• Do NOT try to remove it yourself — you risk breaking it and making it migrate even further.
• See your vet the same day. Quick treatment prevents migration and limits the damage.
• In the meantime, stop the dog from scratching, licking or shaking the area (use a cone if needed).

At the practice, the vet uses long forceps with an otoscope (ear) or an endoscope (nostril, throat), or makes a small incision under local anaesthetic. For deep migrating grass seeds, an ultrasound or a CT scan is sometimes needed to locate the foreign body.

Prevention: good seasonal habits

• Risk season: May to October, peaking in June-July (ripe, dry seeds).
• Avoid walks in overgrown fields, path verges and dry meadows after the grasses have flowered.
• Mow or trim the grass in your garden before the seed heads form.
• Trim the fur between your dog's pads (and around the ears for long-haired breeds).
• Always check your dog after a summer walk:
  • Brush the coat against the grain.
  • Check the ears (outside AND the visible part of the canal).
  • Inspect the paws (between the toes).
  • Look at the eyes (eyelids, inner corners).
  • Check the armpits, groin and belly.
  • Run your hand against the grain over the whole body.
• High-risk breeds: Cocker Spaniel, Spaniels, Springer Spaniel, Setter, Old English Sheepdog, Poodle — any dog with a long coat, floppy ears or used for hunting.
• After hunting or a walk in a risk area: a quick rinse with lukewarm water to dislodge seeds caught in the coat.

Recognising an emergency: when to see the vet immediately

See your vet the same day if, after a walk, you notice:

• A sudden head tilt + head shaking.
• Repeated violent sneezing with a nosebleed.
• A half-closed, watering eye.
• Sudden, compulsive licking of a paw or a specific area.
• A wound that appears and swells quickly.

The earlier the treatment, the less time the seed has to migrate. A seed removed the same day leaves a tiny wound; the same seed 3 days later may sometimes need surgery.

Conclusion

Grass seeds are one of the most underestimated summer dangers for dogs. The harm does not come from venom or a toxin, but from their barbed shape, which drives them forward through the tissues without ever backing out. Prevention rests on three pillars: avoid areas of dry grass, trim vulnerable fur and check your dog after every walk. At the slightest suspicion (sudden head tilt, repeated sneezing, compulsive licking), see your vet without delay — every hour counts to prevent migration.