Dogs sleeping on their owner's bed can result in some problems. Your dogs wanting to sleep with you isn't itself a bad thing. In fact, where your dog sleeps is important for good emotional and physical health. However, letting your dog sleep in your bed can not only develop or further reinforce anxiety and behavior problems, but put you at risk for health problems.
Issues for Humans
If you suffer from allergies, it's not a good idea to let your dog sleep in your bed. Dogs track in dirt as well as pollen and grass. Your bedroom should be pet free to avoid any allergic reactions.
If you suffer from insomnia, having your dog on your bed could make it worse. Tossing and turning could agitate your dog and prolong your ability to fall asleep. Some dogs get up and move throughout the night, which could prevent you from getting a restful, uninterrupted sleep. Other dogs snore.
Dogs pick up fleas and other parasites such as tapeworms. Fungal infections of the skin (known as Ringworm) can be an issue for humans. Ringworm was once thought to be caused by a worm, but it's not; it's a fungus which affects the skin, commonly producing round, red spots on the skin.
Issues with an Adult Dog
Assess your dog's temperament. Make sure your dog doesn't defensively bite or jump when awakened unexpectedly. Even if there are no temperament issues, a dog may bite in self-defense when startled.
Allowing your dog to sleep on your bed could send mixed messages. It lowers your "status" within "the pack". This may make your dog more likely to challenge your authority. If your dog has ever shown aggression towards you, he needs to know who's in charge. Allowing him on your bed only defeats this purpose.
If your dog displays separation anxiety, sleeping in your bed may cause this problem to become worse. Your dog needs to learn to be on his own. It's important for a dog to feel emotionally at ease when physically separate from its owner.
Issues with Puppies
A puppy who is not house-trained should not be allowed to sleep on your bed. Puppies also need to be protected from joint stress caused by jumping on and off furniture.
Puppies also like to chew on things, which could likely result in damage to your pillows and blankets.
Near the Bed Is a Compromise
As an alternative for letting your dog sleep on your bed, you may want to let him sleep at the foot of your bed. It's normal for your dog to want to sleep in your bedroom because the room smells like you. Place your dog's favorite blanket on a cushion or dog bed kept in warm area away from drafts. Only let your dog sleep in your bedroom if doing so doesn't cause aggrevate your allergies.
Be consistent with where you let your dog sleep. Allowing dog napping on your bed when you're not sleeping in it can send mixed messages.