Scale rot, how to identify and treat
Updated: Aug 8, 2021
Scale rot is also known as Ulcerative/Necrotic Dermatitis. Scale rot is a term used by reptile enthusiasts that describes many conditions including blister disease, vesicular dermatitis, bacterial infections, bacterial abscesses, burns, skin abrasions and other forms of dermatitis recorded in reptiles. In laymen's terms - a type of blister infection in a reptile which assists bacteria and fungus to grow on the snake’s skin. Although scale rot is one of the more common reptile ailments is not a condition to be taken lightly. It is a skin disease that may become fatal if left untreated. Scale rot is also contagious. Whilst an untreated condition of scale rot can kill, if picked up in it's early stages it is a condition that can be easily treated and prevented. Scale rot does occur in other reptiles, although snakes are more commonly afflicted. Brownish coloured areas/scale discoloration is usually the first symptom.
Warning signs of scale rot include:
Skin or scales that are cracked or crusty or loss of scales - Shedding issues and illness can leave scales in less than desirable conditions. Scales in poor condition is often an early warning sign to scale rot and an abundance of other issues.
Raised Scales - Snakes shouldn’t have raised scales. Scale rot causes blood to pool, which in turn leads to raised scales. If you are unsure if your animal has raised scales, the easiest way to identify raised scales is to gently run your hand over the animal's body (obviously a venomous snake and particularly aggressive animal needs to be tubed for this). Keep in mind when checking your animals, scale rot is painful for them. Handling may lead to a bite from a normally placid animal. If you do discover raised scales, a closer examination may reveal blisters and discoloration.
Abnormal scale colouration - Ventral scales are usually the first scales to present with scale rot. This is because these scales that have the most contact with the substrate. If scale rot is present scales will usually have a distinct discoloration. Scale rot can turn the scales red, yellow, brown, or greenish black. To not confuse the red with the colouration change that shedding can cause - the appearance is almost as though the scales have been burned.
Blisters - Blisters initially develop without infection usually. As scale rot worsens, the blisters then become infected. Infected blisters are usually pink to red in colour. It is at this time you will probably notice swelling and pus. Pus-filled blisters are not a good sign. Pus-filled blisters on scales may be either yellow or transparent. Blisters may or may not burst. If these blisters are not treated, bacteria is able to infiltrate them. Another outcome here could be fungal infections - its not as common, but it can happened. In some specimens the scales have fallen off where the blisters are located. If infected blisters are not properly treated, the infection can enter into your snake’s bloodstream and cause septicaemia. Septicaemia can be fatal in just a few days. You will see sores and ulcers in the area of infected blisters after the animal sheds. Clusters of blisters can produce blots of skin. Mites can also transmit bacteria into the blisters.
Foul odour coming from the affected area - Pus can smell bad. Pus is a viscous fluid which contains dead tissue, cells, and bacteria. It is often produced when a body is fighting off an infection, especially infections caused by bacteria.
Open lesions - An open wound on a ground dwelling animal will easily become infected. Any open lesion should be treated like it will become infected and special care should be taken.
Loss of appetite - Loss of appetite is something to be cautious of. It may signal an impending normal or positive event such as a shed, male more interested in copulation or even a gravid female. It can also be an early sign of stress. Stress combined with loss of appetite doesn't help an immune system trying to fight off an infection.
Causes of Scale rot:
Part of curing and preventing scale rot will rely on identifying the cause. The main causes are somewhat intertwined. Usually it is a combination of these factors:
Unsanitary living conditions - Good hygiene is one of the most important factors to a healthy life for your reptiles. Weekly enclosure cleans are a great way of keeping on top of this, but removing uneaten food, faeces and sloughed skin should be done as soon as it is noticed. If your reptiles live in dirty enclosures (eg faecal matter uncleaned, sloughs lying around, spilt water) it can lead to health complications like infections. Reptiles are able to pick up bacteria from waste, which in turn has the ability to make the rot even more severe. This can cause the wounds to become infected.
Damaged/raised scales - Bacteria can penetrate areas of damaged skin on your reptiles. If this happens, scale rot can arise. Scale rot will cause the blood to pool. Any of scales where blood has pooled will become raised. Ensure all your cage furnishings are not sharp or broken. Something as simple as a scratch or small wound can lead to scale rot. Mites can also be another reason for raised scales.
Increased humidity levels - Incorrect humidity levels in a reptile enclosure is one of the most common reasons for scale rot. If a reptile doesn’t have enough humidity, it can face difficulties shedding its skin properly. (Among other potential health issues.) An inadequate slough can cause scale rot, as the residual skin can become infected. Too much humidity can keep the substrate from drying out. This also can lead to scale rot as your reptile will always be in damp substrate. This is especially problematic with animals that like to take a swim in water bowls - it gets splashed all over the substrate. Always monitor the substrate -if it gets soaked, replace it. Don't wait for it to dry out.
Incorrect temperatures for your animals - If the temperature in your snake’s enclosure isn’t warm enough, the substrate never dries out. Permanently moist substrate (toiletries, spilt water) can lead to scale rot. Apart from wet substrate, reptiles are ectothermic so you should always make sure that your reptiles have enough heat to perform their bodily functions and stay in peak condition. A cold reptile can suffer assorted health problems.
Vitamin deficiencies - In the wild reptiles don't eat the one thing over and over. They get the vitamins and minerals they need to be healthy from a variety of healthy prey. Healthy prey items have healthy internal organs that are full of nutrients. Cutting costs and getting unhealthy/refrozen animals to feed you pets may not have as much nutrition as they need to stay in peak condition.
Wet bedding - Often, when the temperatures in their enclosure aren't right, the substrate wont dry (toiletries, spilt water). This will create the perfect breeding ground for the bacteria and fungi that can lead to scale rot.
Air exchange/ Inadequate ventilation - Good ventilation in all enclosures is a must. Recycling the same unsanitary air with no flow will not help a reptile any.
Treatment of Scale rot:
It is always best to consult with a reptile veterinarian. Your reptile may need further treatment other than listed below - for example; antibiotics or debridement. If your reptile's scale