The healthy snake is a sleek, symmetrical, well-muscled animal, covered in smooth scales from the nose to the tail tip. Even the eyes are covered by clear scales, called spectacles. Internally, the snake’s organs line up, one after the other to accommodate the long thin body. This anatomy is unique to the snake, but the location of the organs is predictable. As part of your pet’s routine annual check-up, your reptile veterinarian will examine your pet externally and with the practiced skill of palpation, he will use his hands to feel the internal organs. Knowledge of the anatomy of a snake, the location of the organs and the normal variations of those organs allows your veterinarian to make a preliminary assessment of your pet’s health.
The loss of the normal svelte physique and smooth lines often points to health concerns. Pet snakes should be observed daily for changes in their physical appearance or behavior. In addition, most should be handled regularly, and should have their eyes, mouths, skin and vents inspected. When you hold your snake, pay attention to the texture of his skin and to his muscle tone. As he slithers through your hands, take note of any segments of his body which stiffen or do not move normally. A swelling inside your snake will be felt before it can be seen and unusual masses or lumps within or under the skin, or within the body should be investigated with the help of a reptile veterinarian.
- Parasites. Lumps on the surface of the skin are often caused by mites, ticks and other external parasites. These are most often found around the lips, eyes, and cloaca, and when watched carefully with the naked eye or with a magnifying glass, will often move.
Both ticks and mites can transmit bacterial and viral disease. In sufficient numbers, ticks can take enough blood to cause anemia in a snake. Mite and tick infestations often contribute to dysecdysis (abnormal shedding). Treatment of parasites is directed at both the snake and possible parasite reservoirs, or mites, in the environment.
Some worm-like parasites form cystic structures underneath the skin. Superficially, these may appear much the same as lumps, like abscesses. Treatment, however, is quite different, and some testing or investigation is usually required to reach a diagnosis. Encysted parasites are most commonly seen in wild caught individuals, and may require surgical as well as medical therapy.
- Abscesses. An abscess is a pocket of bacterial infection, which in snakes may appear as a firm lump. Pus formed by snakes is solid, unlike the liquid pus formed by mammals. Because the pus cannot be drained, an abscess may require surgical, as well as medical therapy. Abscesses can be just a millimeter or two in diameter, or can grow very large. They may have a scab on the top. These bacterial infections can form at the site of a bite from live prey, cage mates or parasites. In these cases the bite mark may be obvious.
It is also common for snakes to develop many small abscesses within or just under unbroken skin. These are more easily felt than seen. If the infection did not arrive through external trauma, such as a bite, scratch or burn wound, it must have arrived internally. Frequently, skin infection is the outward manifestation of a more serious internal problem, septicemia, or blood poisoning. In these cases, the bacterium that causes the abscesses has been disseminated throughout the body, although we may only see the effects on the skin.
The source of bacteria is usually the snake himself or the prey. Most bacteria, given the right conditions and a host with a weakened immune system, are capable of causing some sort of disease. Some of the bacteria found on and in the body of a healthy, normal snake have the potential to be particularly dangerous. One of the best known is Salmonella. Potentially dangerous bacteria are also found in the snake’s mouth, his digestive tract and waste. Some are found in the blood stream. When the environment is clean and well suited to the species, a snake in good health will not usually become ill; his immune system keeps the bacteria in check. Usually as a secondary invader, fungi can also become involved, complicating an already serious condition. Bacterial and fungal skin infections are generally related to a husbandry problem and should be treated by a veterinarian.
Blister disease is a life-threatening condition in which fluid-filled pockets form under the scales, lifting the scales. The surrounding skin may be abnormally pink, red or moist. These blisters are painful and are prime entry points for bacteria and fungus. Blister disease is largely due to improper husbandry. Usually the environment is inadequately heated, too moist or too dirty. Some bacterial or viral infections cause inflammation of blood vessels, interfering with normal circulation. The resulting fluid build-up can appear similar to blister disease. It is important to inspect the underside of your snake for irregularities in the color and normally smooth, dry contour of the large belly scales.
- Cancer. Cancer can be defined as new growth of body tissues, which is not limited by the usual control mechanisms and while not serving any physiologic purpose, usually occurs to the detriment of the animal. Any of the body’s tissues can be affected, including the skin.