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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 rot is further advanced than a really mild case, your vet may need to prescribe antibiotics (injections) for the remedy or even sedate the animal to remove and clean the infected areas. Supportive care (additional fluids, electrolytes or calorie replacement) may also be necessary. This is particularly true of animals battling severe cases of scale rot. Without proper treatment, it is extremely likely that the bacteria from the scale rot can enter the bloodstream. If this this happens, the reptile will develop Septicaemia. With very mild instances of scale rot, a topical disinfectant in addition with the crucial environmental changes, can be enough to relieve your reptile of their scale rot. A very mild case of scale rot (those that are caught early) should show signs of improvement within 7 days and usually clear up in 3 - 6 weeks. Your reptile's scales should start to look normal after a couple of sheds. However, more severe infections probably will take several months to clear up. Keep in mind when treating your animals, scale rot is painful for them. Handling may lead to a bite from a normally placid animal.

  • Quarantine - Remove the affected animal and immediately put it in quarantine. If you don't have a separate quarantine room, house the animal in a part of the house where no other animals are near it (For venomous species make sure the area used as temporary quarantine is suitable and secure). Use a paper towel as substrate in the new enclosure. Paper towel is soft and absorbent. A white paper towel will show any pus or blood. Ensure the quarantine enclosure is always dry, clean and the temperatures and humidity are correct for your species. Use a small water bowl for quarantine procedures - small enough to drink out, but definitely not adequate enough to soak in - scale rot should be kept dry when not applying treatment. It is best to remove the bowl completely - but you must provide them with fresh drinking water regularly. This should be continued until the reptile has shed all of the infected scales, or until the scale rot has been completely healed by antibiotics. The quarantine enclosure must be kept at a vet level of sanitisation until the scale rot has been eradicated. Use the Chlorhexidine/F-10/bleach solution mentioned below.

  • Clean the old enclosure thoroughly - Remove and throw out any substrate and any porous furnishing. Clean the enclosure with F10 or a suitable disinfectant. Another suitable cleaning method is half a cup of bleach to 4L of water. Leave the F10/disinfectant/bleach on for about then minutes before thoroughly washing off. Wait for the enclosure to dry before reassembling otherwise, you may end up with additional mould or bacteria. Soak any furnishings you wish to keep for 30 mins in the above solution. Remove these clothes and wash yourself before handling any other reptiles.

  • Treat the affected area(s) - this is a two part procedure and should only be used as a complete treatment for a very mild case of scale rot. If further advanced than a very mild case, seek assistance from a reptile vet as this treatment will NOT be sufficient. Disinfect your hands before handling an infected animal, to minimise the risk of further contamination. The first part is a daily Betadine bath. This is especially important for treating blisters. Fill a large container (that has ventilation holes and a lid) with lukewarm (20-26C/80-85°F) water. There has to be enough water for the reptile to fully submerse in, without drowning. One part Betadine is to be added for every ten parts of water. Let your reptile soak for 30 mins and then dry them off with paper towel. Bag the paper towel and throw out immediately. The second part to this process is applying an antibiotic spray or ointment. Ensure the antibiotic treatment doesn't not have a pain-relieving agent. Once you’ve bathed the animal and dried the area, apply the antibiotic treatment. Spray/anoint the affected areas three to four times a day for best results. It’s important to maintain consistent treatment. Be extremely careful to not get it in the eyes, mouth or vents of a reptile. You can also use a chlorhexidine solution to gently clean the affected scales twice each day.

Betadine Antiseptic solution

Betadine Antiseptic Solution.

This is a must have for any reptile first aid kit. It is also safe to be used on humans.

Preventing Scale rot:

Prevention isn't a cure, but it will go a long way to minimising the risk of scale rot. By making sure you have products such as Betadine, and a multi-purpose antimicrobial treatment, F10 on hand can cut down the risk of any problem getting worse until you can attain the products.

  • Know your animals needs - research the species you keep. Know the correct temperature and humidity levels they need, their habitat and dietary requirements.

  • Keep your animal's enclosures clean and safe - You have a duty of care to provide your animals with clean, safe living environments. Avoid using furnishings with sharp edges that can cut or damage the animals, and ALWAYS have light/heat sources covered. Make sure there is a thermal gradient for your animal to keep warm and also cool down. A temperature gun is a great way to check this outside the enclosure, along with thermometers inside the enclosure. If your animal likes a good soak in the water bowl and spills it regularly - use a large bowl that cannot be tipped. We use kitty litter trays for this. Get yourself a decent hygrometer to make sure the humidity in the enclosure stays within the suitable range. Think about where you place your enclosures also - drafts, direct sunlight etc can affect the conditions in your enclosures.

  • Regularly check your animals - The ventral scales are especially prone to scale rot. As are the scales above the cloacal region. It is important to note though, any of the scales on your reptile's body may be afflicted by scale rot. Examine your animals often, but use common sense when doing so. E.g. don’t try handling a snake immediately after a meal. It is important to mention that the red ulcerations typical of scale rot can look quite similar to shedding

  • Good diet - Feed good quality food and feed your animal appropriately. A healthy animal has a much better chance at fighting off any illness than an underfed one. Don't feed live food if possible. Not only is it cruel to the prey items, scratches or bites from them can lead to infection. Always purchase/use quality frozen food from a reputable supplier.

Rough-scaled python, Morelia carinata

Healthy Rough-scaled Python, Morelia carinata


We are not vets and have had no formal training. Drugs contain chemicals and can be toxic, making them dangerous to use on reptiles. ALWAYS check with a reptile veterinarian before using any form of chemical - either in sprays or washes. Always use common sense, follow the instructions on the label, and if there is something you are unsure of - ask for help.

Any products used are at the owner's risk. Unless you see a vet that has reptile knowledge dose rates are generally formulated using sound scientific principles from knowledge of other species. While all due care is taken to ensure the appropriate recommendations are made concerning medications, where medications are used off-label the client accepts all risk of adverse reactions and there is no liability on the manufacturer, the author, or the seller of the product.

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Resources and recommended reading:

Divers S.J. & Stahl S.J. (2019) Mader's Reptile and Amphibian Medicine and Surgery Elsevier, Missouri.

Doneley B, Monks D, Johnson R, Carmel B (2018) Reptile Medicine and Surgery in Clinical Practice John Wiley & Sons, Hoboken, New Jersey

Eipper S.C (2012) A guide to Australian Snakes in Captivity- elapids and colubrids Reptile Keeper Publications. Burleigh. Queensland

Ross J & Rossi R (1996) What's Wrong With My Snake? The Herpetocultural Library, Mission Viejo, California.


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