Spring Cleaning – Spring cleaning is great but, if you are washing your pet's bedding, look at possibly using natural detergents. Cleaning is good as dust mites are another potential cause of skin reaction. Also, when fly spraying, never spray when your pets are in the house and look at ingredients first.
Pollens – Spring is a big time for pollen and most pollen allergies appear like hay fever symptoms.
Plants & Grasses – Some dogs have reactions to certain types of grasses and plants so keep an eye on your pet when you're out and check skin after walks etc.
Fleas – Fleas are something that we need to treat for consistently during the warmer times of the year.
Beaches – Some dogs can pick up rashes and itchy skin from being at the beach. Be sure to rinse your dog or wash them after a trip to the beach to lessen the chance of any itches.
With any allergies, it is important to break the itch/scratch cycle. Dogs will quickly spread a rash over their bodies by the continual itching, licking and biting. To stop this, look at topical products that are designed to help with itches and rashes. There are many natural options in the market. If, however, you are really concerned, then contact your local vet!