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The itchy ears and red rash may or may not be related.
Both could be related to allergies, mites (mange), bacterial infection of the skin -- secondary to these.
The red itchy ears can also be seen with ear mites and ear infection with yeast or bacteria. This can be triggered by allergies --- or can happen alone.
The skin of the inner thighs could be red due to a skin infection or irritation. Licking will make this worse.
For optimal treatment, it is really necessary to see your vet and get a diagnosis of the cause. Without that, we are really simply guessing since there can be a number of causes that could show up this way.
As for ear wash -- hydrogen peroxide can be irritating and too drying on the ears. You can try 1 part white vinegar to 2 parts water. This rinse is mild and can be very helpful in yeast infections of the ear. It does not help in cases of mites or allergies.
As for the rash on the skin -- triple antibiotic cream and hydrocortisone cream can be mixed and used on the area, 2-3 times per day. It needs to be left on (not licked off). Be sure to use cream not ointment (as it traps moisture).
I hope this information helps!_____________________________________________________________________Please click "ACCEPT" if the information I have provided has been of help so I receive credit for my work. Bonuses are always welcome and appreciated. Thank you.The above is given for information only. Although I am a licensed veterinarian, I cannot legally prescribe medicines or diagnose your pet's condition without performing a physical exam. If you have concerns about your pet I would highly advise contacting your regular veterinarian