Thank you for using Petco Pet Education Center, formerly Petcoach! I can see that Bauer has some red and raised areas in his underarm. This may be caused by a skin infection, exacerbated by allergies, which can be itchy. I recommend limiting Bauer's diet to only his regular dog food and using a gentle antibacterial dog shampoo on the area. If it does not improve over the next several days, Bauer may need to be seen by his vet for antibiotics. I hope this helps and that all is well!