What causes dark patches on my dog's belly? Is human lotion safe?

Thanks for using Petco Pet Education Center, formerly Petcoach! This looks like it could be a skin infection. You can try to use a medicated shampoo containing chlorhexidine twice weekly for 2 weeks. If there is no improvement or in the meantime this appears to be getting worse, have her evaluated by a veterinarian for further assessment and treatment. Good luck and have a good night!

If the skin is not irritated/itchy and feels the same as the skin surrounding that is not dark in color, I would just monitor the area. We can have changes in pigmentation of the skin in dogs as they age, as well as changes as the result of inflammation. If the area begins to spread, or the skin feels dry/rough in this area, or she is licking, a visit to the vet is recommended.

This could indicate a yeast or fungal infection as well as a bacteria infection of the skin. As the over the counter shampoo hasn't worked the next step is for your veterinarian to do an exam, determine if/what infections are there and what medication is needed.

It is very difficult to tell from a photo exactly what is going on here. I am concerned if these areas could be bleeding under the skin. From the photos the areas don't appear raised which is why I am concerned they could be this type of bruisng, also called ecchymosis. If you press your finger onto the area and remove it, and there is not a white spot, then this is a sign this is ecchymosis and your dog should be seen right away because it could have a bleeding disorder. If you press against the red area and when you remove your finger it blanches (turns white) and then turns red again, then it is less concerning in terms of the urgency of being seen and is more likely an actual skin issue. If the area is raised or crusted then this could be inflammation due to infection with bacteria or yeast. We can have immune system over-reactions that can result in red inflammed areas of skin. We can also in more rare cases see cancers that can affect the skin. A vet can examine the skin and determine what testing may be indicated- this could include cytology of the skin, culture of the skin, biopsy, or bloodwork depending on their exam findings. Best of luck to you.

I’m not sure if the lighting makes the skin look normal in your picture, or if the rash you are describing is faint enough to not show up on the picture, but her skin appears fairly normal to me. The brown spots I see are normal pigmentation variants. Often times mild skin problems in young dogs are bacterial and bathing in a shampoo that has chlorhexidine or salicylic acid can be helpful. These can be found in the human shampoo aisle in the dandruff area. If it does not seem to help then I would encourage you to have her evaluated by your veterinarian soon. Best of luck and thank you for using Pet Coach.

The pictures look like it could just be normal pigment change. As puppies mature their pigmentation can as well. If the skin is raised, thicker, crusty, or itchy then I would be concerned. If you have any concerns then I would encourage you to have him evaluated by your veterinarian. If there is a concern then a biopsy could easily be done at the time of his neuter. Best of luck and thank you for using Pet Coach.

Darkening or changing skin color can be due to disease including allergy, flea infestation, bacterial skin disease or fungal disease. Change of skin (or even hair) color can also be completely normal especially in puppies and young dogs.