Bumps in dogs can be due to variety of issues. Plugged fair follicles can lead to bumps as well as bug bites, bacterial infections and fatty masses or lipomas. The more serious bumps consists of things that are cancerous such as mast cell tumors, squamous cell tumors and basal cell tumors.
If your dog has a bump on their skin that appears to be increasing in size, changing in color or consistency, or rapidly growing , you should have it checked out by your veterinarian. Growths such as mast cell tumors which are common in dogs can easily be treated through complete excision if caught early.
Bumps due to bacterial infections will require antibiotics. First time infections can generally be treated with a board spectrum antibiotic. If your dog however has had repeat skin infections, they may require a culture and sensitivity in order to select the appropriate antibiotic.
Depending on the appearance of the skin lesion, your veterinarian may take a small sample of cells using a needle, skin blade, or tape in order to determine the nature of the growth. This process however is sometimes inconclusive and may require a complete excision of the mass with biopsy in order for a correct diagnosis.