A messy bottom is both uncomfortable and unsanitary, inviting worse problems such as skin scalding and even fly strike. While your vet does the detective work, it's up to you to keep the bunny comfortable. One way is with a careful, gentle "butt bath" to keep caustic bodily fluids away from the skin. There are two methods one can safely use to clean a messy bunny: Dry or Wet. Of the two, a dry bath is usually preferable if the mess on bunny's bum is dry.
If the bunny is extremely soiled and smelly, a wet bath may be necessary. (Instructions for this procedure follow those for the dry bath.)
3. Liberally apply the cornstarch to the soiled areas, and gently work the powder around messy poops, into the fur, and down to the skin.
4. Work the powder around any stubborn clumps of debris gently. As the cornstarch coats the mess, it will slide away easily.
5. If necessary, use a fine-toothed flea comb to gently tease away dried poop or other debris. Don't pull too hard, as the bunny's delicate skin can tear surprisingly easily.
6. Pat the powdered areas well to remove loose powder. If possible, have a hand-held vaccuum close by to suck up the powder. Better than you and bunny inhaling it.
Bunny should be clean and fragrant in just a few minutes. Rabbits generally don't mind a dry bath, and will sit quietly as the soothing powder takes away the sting of urine burn.
Wet Bath Procedure
2. Fill a bathroom sink to about 2.5" depth with lukewarm water.
3. Mix in about a tablespoon of shampoo, and mix well.
4. Being firm and gentle so that the bunny cannot jump and injure himself, lower his rear end into the lukewarm shampoo/water, and gently lave the solution onto the soiled areas until they are clean. If the bunny is very messy, you may have to change the water and do this a few times.
5. Rinse with lukewarm, clear running water very thorougly, leaving NO shampoo residue.
6. Towel dry carefully, being sure not to rub too hard against irritated skin. Microfiber towels, are excellent for this purpose. They're very soft, and they absorb wetness better than conventional cotton or cotton blend towels.
7. Blow dry on low, keeping your hand close to bunny's skin so that you can tell if the air flow is too hot. (The last thing you want to do is burn already inflamed skin!) Use a fine-toothed flea comb or a soft brush to separate the hairs and make drying time shorter.
8. When bunny is fluffy-dry, carefully clip away the fur on the areas where the skin is irritated. If you can't see the skin, or are doubtful where skin ends and fur begins, then do not clip! Rabbit skin is very thin and stretchy, and even a small wound can expand to alarming proportions!
9. Apply a soothing balm, such as Calendula (from the Health Food Store) or triple antibiotic ointment (e.g., Neosporin, but not Neosporin Plus, which contains topical anesthetic and is not recommended).
10. Repeat as necessary, but do not continue if rabbit seems unduly stressed by the experience. Whenever you handle a bunny, it's important to be firm, gentle and ready to release the bunny at ground level if she starts to struggle violently. As you probably know, one good kick can subluxate or even fracture the spine. Always keep the bunny's safety first in mind if you attempt a project like this.
And remember, the "butt bath" is usually merely treating the symptom of a more complicated disorder. The most important thing to do is to discover why your bunny has urinary incontinence or runny stool problems, and get to the root of the ultimate cause for a complete cure.
For tips on how to determine what's wrong with a sick bunny, please visit Rabbit Health Central. Good luck!