Why Does Grass Make Us Itch? (Solved!)

So it turns out that grass is an evolutionary marvel that has multiple ways of protecting itself against predators – including us by extension, by making us itch.

Grass has razor sharp edges and tiny bristles called trichomes, and some grasses have microscopic shards of silicon called phytoliths that can cut our skin and cause itching as we sweat. Allergies combined with some grasses also secreting an itchy fluid, mean grass can make us itch in many ways.

Let’s dive down into the subject of how and why grass makes us itch in more detail, and discover some remedies to help us stop the itching…

Why Does Grass Make Us Itch?

Why Does Grass Make Our Skin Itchy?

The grass in your lawn has enemies. There are many grass predators, large and small. So, grass has developed ways to fight back. Blades of grass fight back with razor sharp edges, tiny bristles, and shards of silicon. These defense mechanisms slice and scratch their prey.

Then, we sweat. The salt from sweat gets in those tiny cuts and scratches and it itches – like crazy. Not only do the cuts from grass make us itch, we humans often have grass allergies.

If you examined a blade of grass under a microscope, you would see that the edges of a piece of grass resemble a bread knife – serrated and razor sharp.

Then, on the surface of the blade of grass, you would see that there are thousands of tiny bristles. The bristles are called trichomes

Trichomes are common in the plant kingdom. They discourage predators from chowing down on leaves. For humans, the trichomes make tiny scratches on your skin. Then you sweat, and then you itch. 

To make matters worse, some grasses secrete an itchy fluid.

Another mechanism grasses use to discourage predators is called a phytolith. The Greek word phytolith combines phyto (plant) and lith (stone). Phytoliths are tiny shards of silicon. Not all plants have them, in fact not all grasses do. 

But for those that do, phytoliths help keep their leaves from being devoured. Turns out, eating small shards of silicon is not very appetizing. 

The phytolith/plant partnership has been around for millennia. While grasses die and decay, the silicon survives. Because phytoliths have unique shapes, depending on the grass type, the leftover phytolith can help identify the long-gone grass. 

In fact, scientists can identify Jurassic grass species from Jurassic phytoliths in the Jurassic sized piles of Jurassic dinosaur poop. Here’s a fascinating link with Jurassic phytolith (and poop) photos.

Then, there’s grass allergies. Many, many people are sensitive to airborne pollen or allergic rhinitis (aka hay fever). The CDC (Center for Disease Control and Prevention) reported that around 19 million adults and 5 million children suffered from hay fever in 2016 alone.

Grass sends out sticky, microscopic pollen in the late spring and early summer. Symptoms include the usual suspects of runny nose, itchy eyes, sore throat and  headaches.

Some adults, many babies and many small children are sensitive to grass pollen touching their skin, called contact dermatitis. It makes their skin itch when they walk barefoot or roll around in grass.

Does Everyone Get Itchy From Grass?

Not everyone suffers from grass allergies. But everyone suffers from the thousands of tiny cuts and scratches inflicted by grasses.

Human skin is amazing. It has millions of tiny receptors that deliver messages to our brains. If something irritating happens on the skin, the sensors send the message to the brain – get it off! 

In response, the brain urges the fingers to go to the spot and dislodge whatever it is. A bug. A thorn. Or to itch the spot.

How Do You Know if You’re Allergic To Grass?

For those of you who aren’t allergic to grass but may have tiny cuts from grass, your skin will have many very small red bumps and the area will itch. If you have a contact allergy to grass pollen, then you will notice bumps and rashes

In extreme cases of contact dermatitis, the skin will be very red, feel like a burn and may even blister.

If you are very allergic, your breathing may become impaired. Call an emergency hotline immediately.

How Do You Stop Itching From Grass?

If you have spent some time in your yard and notice that you’re itching your skin, first, get out of those yard work clothes. Then, give the itchy area a good clean with mild soap and water

If lots of parts of your body are itchy, try a shower (the colder the better). Be sure to rinse or wash your hair, where pollen collects. 

To avoid grass cuts and scratches, gear up. Wear long sleeves and long pants when working in the yard. Some experts say that wearing sunglasses will help keep pollen out of your eyes. A hat will help keep pollen out of your hair.

Be sure to throw those yard work clothes into the washer and dry them in the dryer – not on a clothesline.

How Long Does Grass Allergy Last?

Unfortunately, the answer here is that a grass allergy will last as long as grass pollen lasts. For northern grasses, the period is late spring to early summer. With southern grasses, pollen can be produced throughout the year.

Grass pollen is small and light. It has been known to travel hundreds of miles on a good wind. Many places online will give you your area’s pollen count daily. Check the day’s pollen count before mowing the lawn and avoid the lawn on dry, hot, windy days.

The Asthma and Allergy Foundation of America (AAFA) says that some grasses have more pollen than others. Bermuda grass, Johnson grass, Kentucky grass, Orchard grass, Rye grass, Sweet Vernal grass and Timothy grass are the worst. Here’s the source.

For allergy sufferers, experts recommend washing or rinsing your hair before bed if you’ve spent a long day in the yard. Rinsing your hair will get rid of pollen. Then, you won’t spend the night with pollen on your pillow.

If you have grass allergies but can’t avoid mowing the lawn, an N95 mask can help.

If you suffer from grass allergies, you may want to treat your allergic symptoms with an antihistamine like Benadryl. Be sure to check with your pediatrician if you are giving antihistamines to a child. 

If all the home remedies and over the counter medications aren’t working, then you may have to see your doctor. There are two types of immunotherapies available for hay fever: allergy shots and allergy tablets.

Allergy shots are given by your doctor. After a pollen test, shots can be given subcutaneously for specific ones. Over time, the dosage increases until you are immune. This method may take up to three years to complete but then you are immune to that pollen.

Allergy tablets are relatively new. Sublingual immunotherapy tablets (aka SLIT) can be taken at home. The tablets are used before and during allergy season. The tablets are dissolved under your tongue for 1 to 2 minutes before swallowing. 

Grass allergy

How Long Does Grass Rash Last?

Doctors say that a grass rash can last from a few hours to 10 days.

What’s The Best Anti Itch Cream For Grass Allergies?

Most experts recommend a corticosteroid cream. Hydrocortisone decreases inflammation and helps with itching. Another lotion to try is calamine

Can Vinegar Stop Itching From Grass?

Yup! Another amazing use of lowly vinegar. Soak a cloth or round cotton facial pad with apple cider vinegar and apply it to the itchy area

Here are some other home remedies to stop itching.

  • Heat. Soak a cloth in warm water and apply to the area.
  • Cold. Soak some cloths in cold water and apply them to the itchy area.
  • Oatmeal. Make a paste with one part oatmeal to one part water and spread it on.
  • Mud. If you don’t have any, make some!
  • Baking soda. Add a cup of baking soda to a tub of warm water.
  • Honey. Honey is a natural antibiotic that can be used on lips, dry skin and itchy areas.
  • Citrus fruit. Rub the juice or the peel onto the bite. Sure, citrus juice on tiny cuts will sting – but only for a few seconds.

Conclusion

The wonders of the natural world never cease to amaze me – and that extends to the grass in your backyard too (albeit on a smaller scale).

To discover that grass has evolved to be extremely adept at deterring predators is incredible – even if the side effects of this are tiny cuts on our skin that cause itching, and grass allergies that also make us itch.

All this reminds me (again) of that great movie ‘Honey I Shrunk The Kids’ (which I loved myself as a kid). The tiny children spend all their time dodging giant ants, spiders and others bugs. But with all its razor sharp edges and silicon shards – perhaps they should have been more worried about the grass. 🙂