When dogs lie down, their stomachs are in contact with whatever surface they're on -- so they're exposed to household chemicals, outdoor irritants or insect bites, all of which can lead to rashes. Most rashes are harmless and can be treated with topical ointments, but some skin irritations signify serious conditions. If your dog scratches at a rash, have him evaluated by a vet.
Ticks, fleas, mites and chiggers can all cause stomach rash on a dog. Not only do the bug bites lead to raised welts and itchy skin, but your dog's licking and scratching of the area can lead to dry and irritated skin or hot spots that exacerbate the problem. Treatment includes identifying and eradicating the parasite problem, thoroughly cleaning your dog's bedding and washing his stomach with an antibacterial soap. A topical anti-itch cream or prescribed cortisone cream can further soothe itchy skin irritation.
Contact or Allergic Dermatitis
Just like a human, your dog may be allergic to something the skin of his sensitive stomach comes in contact with. That could be sap from a tree, poison from a plant or yard fertilizer, or it could be a carpet, floor or household cleaner. While allergic rashes can typically be treated easily enough with topical creams or vet-prescribed antihistamines, narrowing down and avoiding the cause of the irritation can be tricky. Consider using pet-safe supplies in your home and garden to reduce the potential for rashes and accidental poisoning.
Folliculitis and Impetigo
Folliculitis, a bacterial infection, may follow other skin problems that result in scratching and raw, exposed skin. Symptoms include sores, raised welts, scabbing or scaly skin. Fluid-filled blisters on the stomach can be a symptom of another bacterial problem, impetigo, which is most commonly seen in puppies. Your vet may treat both disorders with medicated shampoo or antibacterial gel. An antibiotic may be needed to treat infection.
Some skin conditions signify serious underlying medical conditions, such as internal parasites, strongyloidiasis, mange or an uncontrolled infection. If your dog experiences sudden changes in his coat or skin, particularly if the change is accompanied by other distressing symptoms like vomiting, bloody stool or a change in appetite or demeanor, seek veterinary attention immediately.