Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that your pup is developing crusty sores on her neck that are worsening despite your efforts cleaning the areas with hydrogen peroxide and giving her a Benadryl for itching.These are usually hot spots
or superficial pyoderma lesions.Hot spots are caused by the skin getting wet, sometimes from swimming or bathing and not getting dried off properly but most of the time they come from a dog licking
, chewing or scratching an itchy area and breaking the skin barrier, allowing bacteria that normally live on the skin to get in the skin and thrive. They can be secondary to a bug sting or bite. Once the dog starts itching the primary lesion they can create more with their scratching, thus her seeming to get more lesions.If these are truly hot spots then getting her to stop scratching the skin to heal should help in your efforts to resolve them. This likely involves treating the underlying allergic reaction and the lesions themselves. Allergies are the most common cause of itchy skin. I'll give you an allergy rundown of likely causes for skin troubles. She may have more than one allergy given how symptomatic she is now. Dogs that have one allergy often develop several with time. The effect of multiple allergies aren't additive, they actually compound one another. Allergies are not something that we cure, we can only control them so they can be quite frustrating.Even if you don't see fleas I do recommend using protection. They are the most common allergen 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
. Other allergens can be inhaled (like grass pollen, dust mites or molds) and you can use a combination of antihistamines and high doses of omega-3 fatty acids to help with those (they also help with the symptoms of flea allergy). In combination fatty acids and antihistamines work synergistically, much better than either one alone. If her symptoms worsen seasonally I would think that inhaled allergens are a part of her problem. You can try:1)Benadryl (diphenhydramine only don't use the combo products as they can be toxic) at 1mg to 2mg per pound or one 25mg capsule per 15-25 pounds of dog orally every 8 hours. I know you've tried Benedryl but I want to make sure you've used an appropriate dose. OR 2)Claritin (loratidine) at 5mg per 25 pound dog once or twice daily. OR 3)Hydroxyzine at 1mg per pound orally every 8 hours. OR 4) Chlorpheniramine at 4mg to 8mg per dog once or twice daily.Some dogs do better on one antihistamine rather than another. Give the one you pick a week trial and if it isn't working try another. Be aware 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, meaning if she is between doses pick the higher one. I recommend a 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 an 80 pound dog could take 1600mg of EPA per day.Clip the hair in the area around and over the lesions 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. DO NOT use peroxide. It is highly irritating and can kill healthy tissue, making her even more itchy. If she isn't much improved in a few days then she may need to see her veterinarian for oral antibiotics, the infection may have invaded too deeply for topical treatment to work. Please let me know if you have any further questions.