After spending a few days at the park our dog came back scratching his arms and groin with lesions (red patches) on his groin. What is the cause and treatment?

Hi Cheryl,

Thanks for your question.

I’ve certainly seen this type of case before and I believe it could be one of two possible issues. I can’t really see much that helps in the picture that you sent so I can’t be certain about either diagnosis. It’s really important that you know that the advice I give in this answer cannot be relied upon because in a case presentation like this, the opportunity to perform a physical examination is vitally important. So regardless of my response here, I strongly suggest you see your veterinarian about this at your earliest convenience. However, I can give you some thoughts that would likely not contribute to the condition worsening and may help it resolve.

The first possibility is a bacterial skin infection. In a visit to a beach environment, your dog will be exposed to a few things. He likely ran in and out of the water which will cause his skin and hair to be wet, especially underneath him and between his legs where airflow wouldn’t reach very well. This would create a good environment for bacteria to grow and he could have a simple superficial bacterial dermatitis. To treat this, you could shave or cut some of the hair away. Clean it with an antibacterial soap or antibacterial shampoo on a daily basis always making sure you dry the area thoroughly afterwards. Applying an over-the-counter antibiotic cream twice a day would help as well. Keeping your dog away from it with a cone would be ideal because the constant licking and biting that he is doing will further moisten the area and aggravate it. This is a safe general treatment you could begin regardless of the cause of this and you won’t be doing any harm. If it doesn’t improve within a few days, I would recommend you see your veterinarian. If you want to give your dog some relief from the irritation and itchiness, I would recommend you ask your veterinarian for a medication to calm the reaction so he can eliminate the discomfort he is currently experiencing.

It’s possible this is an allergic reaction. This is less likely given the distribution of the lesions. In the sand there are particular insects that will bite dogs and they’ll have an allergic reaction to them. I’ve seen it many times before but it would tend to be distributed around the entire abdomen rather than just the groin area. Since it isn’t, this is why I believe a bacterial infection is much more likely. If it is an allergic reaction, you can certainly do the same protocol as for a bacterial infection, but also add another treatment to settle allergic reactions. You could administer an over-the-counter antihistamine and apply an over-the-counter ointment to the area that has an anti-inflammatory effect such as cortisone. Again, this is less likely to be the cause of these lesions but performing this treatment should not be detrimental.

The ideal thing to do is to get it diagnosed by your veterinarian. Any skin lesions should have a ‘skin scraping’ performed. This is a quick, inexpensive test where they scrape the top layer of the affected skin and look at it under a microscope. This test looks for various infectious agents such as bacteria, yeast and mites. This way you can identify the cause and start the correct treatment right away.

I hope this helps and good luck.

Dr. Greenway