Grass awns are small seeds which have one pointed end, whilst the other end is feathered. The picture shows the general size in comparison to a penny. Sometimes, the feathering and barbs can be much more florid and dramatic than on the one seen here.
Grass seeds are abundant at this time of year and so dogs and, to a lesser extent, cats are prone to collecting them in their fur when moving through long grass. Many will stay within the fur and then fall off again – indeed this is a dispersal mechanism for the seed – or they may be groomed out by the owner.
However, sometimes they will penetrate into the body using the tapered end to puncture the skin. Once inside, the barbs and feathers prevent backward passage and so the seed is trapped. The most common way we see these in the clinic is with a small hole in the skin, such as the one shown in the picture of the skin between the toes of a Labradoodle. The wound will be painful and dogs will lick persistently at it. An inflammatory response will occur as the body sees the seed as foreign material – the surrounding skin is reddened and watery, bloody fluid will run from the wound. In some cases, we can put a pair of forceps into the wound and retrieve the seed, but in others the pointed seed will have continued to penetrate away from the site of entry and these can be very tricky to find.
Seeds are most likely to penetrate the skin in areas which come into contact with them under pressure such as the feet or the bottom when the animal sits down. They can also get into ears and up noses causing great distress, with pain and pawing at the ear or nose. These cases usually require removal under sedation or general anaesthesia as the affected area is so painful.
The most serious problem occurs when an animal inhales a grass seed. This is most likely to occur when the dog or cat is running through long grass and breathing strenuously. Once the seed enters the air flowing in with inhalation, it is quickly gasped down into the lungs before it lodges. This causes a localised pneumonia in the area and sometimes an abscess may form. The seed can remain lodged or it can start to migrate further, once again with its pointed end forming a burrowing device. Affected animals will be coughing and often markedly off colour with a temperature. X-rays can show an affected area of lung and this can resolve with antibiotics if the seed is small and disintegrates into pus, but often they need removing with a bronchoscope (a thin endoscope which can be put into the airways under general anaesthesia – it usually finds a tell tail trail of pus which can be followed right to the site of the seed!) and occasionally, in very severe cases, thoracic surgery is required to remove the whole lung lobe.
For such a small and inconsequential object, a grass seed can cause a myriad of problems and it is quite remarkable how many different places they can turn up!!
Mark Maltman
Maltman Cosham Veterinary Clinic
Lyons Farm Estate
Lyons Road
Slinfold
W Sussex, RH13 0QP
01403 791011
