This is another “catch-all” term for a variety of conditions that can include bacterial, fungal, or environmental factors. In most forms of shell rot, micro-organisms get under the protective layers of the scutes and begin to “eat away” at the tissues they find there. This means that there needs to be a pathogen in the habitat, and usually some form of damage to allow it to get under the top layer of scutes. An example of a specific form of this type of shell rot is Septic Cutaneous Ulcerative Disease (SCUD), which is caused by the bacteria Citobacter freundii, most often associated with shellfish. SCUD is most often associated with aquatic chelonians.
“Wet” shell rot (dark pockets or pits, bad smell, etc.) is most often bacterial, while “dry” shell rot (“cheesy” growths) is rarer and usually fungal, but any form of rot causes damage that invites secondary infections and other complications. Shell rot can eat deeply into the shell, causing more severe issues, and even death.
- Minimize the growth of bacteria, viruses, molds and mildew in the habitat.
- Arrange the environment to minimize scratches, abrasions, and chips to the shell.
- Prevent overly-wet substrates. These conditions can lead to environmental “rots” that behave like “immersion foot” does for humans. In my opinion and experience, wet acidic materials such as sphagnum mosses seem to make things worse.
- Bacterial and fungal forms of shell rot are infectious, so new animals should be quarantined and if one animal shows it, all animals should be monitored.
- Isolate the affected tortoise(s) someplace with a dryer, cleaner substrate (see Nursing Care).
- Correct any issues in the habitat, environment, cares, and diet.
- Clean the affected area with gentle scrubbing or scraping to remove loosened materials. Try to remove all dead, dried-out, or damaged scute materials, but do not force anything.
- Swab the area completely with a multipurpose skin disinfectant such as Betadine Solution. Let dry completely. Betadine is effective against many micro-organisms, but also inhibits healthy growth so do not use it past the first 2-3 days. This may be all you need to do for a minor case.
- Treat the affected area twice a day with an antibiotic ointment, preferably something like silver sulfadiazine ointment or 2% mupirocin ointment. Keep the tortoise on newspaper or paper towel for a couple of hours to let the ointment work.
- Repeat ointment for about a week. Re-evaluate.
- If the antibacterial is not doing anything, switch to or add an anti-fungal ointment. Any over-the-counter antifungal used for humans will work, such as that for athlete’s foot or “jock itch”. Use for a week like steps #5 and 6 above.
- Contrinue treatment until the plastron is smooth, dry, odor-free, and shows no signs of discharge.
- If it does not help, see a vet or other expert.
Most forms of shell rot, caught early and treated aggressively, should be OK although it may take months or even years for some of the shell damage to fully heal and there may always be scars.
Edited 2-25-2013 (C) Mark Adkins