Check out this website regarding ulcerative dermatitis.
http://www.redtailboa.net/subj_index152.html
Ulcerative Dermatitis (Scale Rot)
Symptoms: Discolored (pink, red, or brown) ventral scales, Chipped Ventral scales. Usually only 1 to 3 scales are infected but often breaks out in multiple areas. Sometimes it effects only part of the infected scales.
Causes: The most common cause of Scale rot is one that can not be avoided. Infections often start from within the animal and work their way out to the skin. The most common husbandry cause that CAN be avoided however is bacteria grown in dried urates left in the cage, especially in the basking area. When a snake lays in this to bask, the combination of heat and the bacteria found in feces and urates can become deadly. Another cause is overexposure to damp substrate or oversoaking. Snakes with mites will soak for extended periods to drown them. This will sometimes cause scale rot. Ball and blood pythons seem to be the most susceptible of the boids but any reptile can have this condition.
What to do: Neosporin, Polysporin, or any Triple antibiotic ointment that does not incorporate Lidocaine or any pain medicine is very effective in clearing this up. Remove all substrate and clean or keep the infected snake in a secure plastic storage container with air holes and a water bowl large enough to drink from but too small to soak in while treating. It is normal for no apparent improvement to be noticed until the next shed. But, any skin irritation such as this will cause a snake to go into a shed cycle, sometimes even back to back sheds until it all clears up. Keep rubbing Neosporin on the bad scales twice a day and make sure the snake is clean and dry. Being allowed to burrow or crawl through any substrate at this time is a bad idea. There is no way any Neosporin will remain on the snake's belly and there is no way to keep it clean. This is why it is important to place the animal in a substrate free enclosure during treatment. If at any time redness spreads out over a larger area than where the infected scales are or if any puss oozes from the wounds, or it continues to get worse, a trip to the vet will be necessary. At this point the infection could very well become septic. Septicemia (blood poisoning) will quickly spread to multiple vital organs and kill the animal in as little as six weeks so a series of antibiotic injections will be needed.
