Diphenhydramine (which is the active ingredient in Benadryl) can be dosed at 1 mg/pound body weight every 8 hours. This may help some itch and inflammation.
The concern is the in the skin there can be opportunistic bacteria and yeast that can proliferate to higher levels and can potentially cause skin problems. This is seen more often when there is skin damage by way if moisture or damage. The excess moisture can allow the normal yeast and bacteria that colonize and to proliferate to higher levels, as these levels increase then more issues may arise. Topical shampoos with chlorhexidine and miconozole can assist with yeast and bacteria control. When shampooing it is best to allow for a minimum of 10 minutes of contact time with the skin before rinsing it off. This contact time is critical to provide good kill down and penetration to the area for potential organisms. These topical items like chlorhexidine and miconozole can also be sprayed on the skin. (Micochlor spray is my an example ). This can be applied to the area 2-4 times a day. They can kill the yeast and bacteria as they are applied. This can be done in conjunction and between the shampooing. The chlorhexidine can address yeast and bacteria and the miconozole will also will address yeast. There is a topical spray that has lidocaine and hydrocortisone in it. This can be sprayed onto the red and itchy skin to alleviate much of the clinical signs also. This can be done 2-4 times a day as needed also the reduce itch and inflammation. The following are some example to look for, these can be found over the counter like at pet stores, pet section in some stores or online like at Amazon . It is generally more effective when the two different types of sprays are used together as explained below.
1. Micochlor Plus Shampoo which has chlorhexidine and miconozole in it to assist with yeast and bacteria.
2. Thomas Labs MicoChlor Plus Spray
The chlorhexidine will help to clean and disinfect and to address yeast and bacteria. The miconozole will address yeast also.
3. SynergyLabs-Veterinary-Formula-Clinical Care. Premium Itch Relief. The lidocaine and hydrocortisone will help with itch, pain and inflammation.
The shampoo may not be needed to cover the whole body however focussing on the affected areas. Synergy is most important in the above discussion. The one spray with chlorhexidine can address potential bacteria and yeast and the other spray with the hydrocortisone can address the inflammation and itch. Together the two items work very well together.
These items are over the counter and can be found at pet stores, the pet section like at Wal Mart or Amazon. I gave one brand example however many different brands are available. Most important is to look for the same active ingredients.
If you are outside of the USA here are some other products that may be more readily available in your country.
The following are some example to look for, these can be found over the counter like at pet stores, pet section in some stores or online like at Amazon.
Duoxo pyo (these items all have Chlorhexidine and Climbazole in them)
Duoxo pyo spray
3. The Triz Chlor line also has these Ingredients also. Here is a link to review.