Hello, my name is***** and I have over 20 years of experience as a veterinarian.
I'm sorry to hear about your girl Zeus's rash/pimples on her belly and I understand your concern for her.
Does her rash look like that in the link below?:
If so her rash is likely a superficial infection of the skin called staph dermatitis.
It is caused by normal skin bacteria getting introduced under the skin by the dog scratching, licking
or chewing at itchy skin. Itchy skin is normally secondary to allergies of some type or skin mites.
By the time we see a rash they generally need a skin scraping to look for mites and oral antibiotics but there are some things we can try at home to help.
Clip the area around and over the rash very short and use a solution mix of Betadine solution and warm water, made to look like weak tea, and clean the affected areas twice daily. This is an antibacterial and will dry the lesions out to allow them to heal. It does stain horribly though so you probably want to do this outside. Another option is cleaning the area with chlorhexidene shampoo and warm water, then rinsing and patting the area dry.
If she is licking the area then I recommend placing an Elizabethan collar on her as the more she licks the worse the rash will get.
If her rash isn't much better after 3 to 4 days of treatment she will likely need to see her veterinarian for oral antibiotics and a skin scraping.
Even if you don't see fleas I do recommend using protection. They are the most common allergen causing itchy skin and a rash and it only takes one bite a month to make an allergic dog scratch so I recommend using flea prevention even if you never see one again. Frontline Plus, Advantage II or Advantix are excellent. Don't use over the counter products, especially Hartz or Sargents, as most are ineffective if not toxic
To soothe her itchy skin you can try giving an antihistamine and an omega 3 fatty acid:
1)Benadryl (diphenhydramine only don't use the combination products with acetaminophen or decongestants as they can be toxic for dogs) at 1mg to 2mg per pound or one 25mg capsule per 15 to 25 pounds of body weight orally every 8 hours.
OR 2)Claritin (loratidine) at 5mg per 25 pounds of body weight dog once or twice daily.
Be aware that antihistamines can cause sleepiness or hyperactivity in some dogs. These side effects do wear off with repeated use.
Omega-3 fatty acids are fish oil products. 3V by DVM or Derm Caps ES are good brand name products. Use the high end of the dosing schedule for your pup's weight. I recommend a fatty acid dose based upon the EPA portion (eicosapentanoic acid) of the supplement as if we do that the rest of the supplement will be properly balanced. Give her 20mg of EPA per pound of body weight per day. For example a 15 pound dog could take 300mg of EPA per day. Antihistamines and omega-3 fatty acids work synergistically, better than either one alone.
Please let me know if you have any further questions.