tpvets_logo.jpg (2726 bytes)TOA PAYOH VETS
      Date:   21 May, 2012  

Focus: Small animals - dogs, cats, hamsters, guinea pigs & rabbits

Toa Payoh Vets Clinical Research
Making veterinary surgery alive
to veterinary students using real case studies and pictures

No Smoke Without Fire - No Scabies Without Mites?
Dr Sing Kong Yuen, BVMS (Glasgow), MRCVS
21 May, 2012 
Be Kind To Pets
Veterinary Education
Project 2010-0129

"My dog scratches her face vigorously, non-stop last night," the lady with red eyes showed me a young Shih Tzu with bright red cheek, ear and eye areas. "Is she suffering from an allergy?" Her friend had brought her in to Toa Payoh Vets on this fine Saturday morning, May 12, 2012.

I was present from 9 am as I was conducting a "trust and audit" process on Dr Jason Teo. This is part of effective management of a licensee to ensure a high standard of veterinary care and to rectify errors and omissions of the practice.

"I remember your case," I said to the lady friend as I fished out the card assuming that the affected dog belonged to the introducer. The referred lady who had red eyes said: "I just want a second opinion. For the past one and a half weeks after treatment by Vet 1, my dog is not getting better. She is still very itchy and her skin is full of red sores."

I put the dog on the examination table and viewed the records and medication of Vet 1.

scabies-ringworm-young-female-shihtzu-toapayohvets-singapore scabies-ringworm-young-female-shihtzu-toapayohvets-singapore
tpvets_logo.jpg (2726 bytes)5306 - 5307. Itchy and crusty ears. Scabies and ringworm in a young female sibling Shih Tzu of one owner

"Most likely, your dog has scabies," I pointed to the crusted lumps on the ear edges. "Just like your friend's dog I treated some 4 weeks ago."

"No," the lady with the red eyes showed me a bottle of an anti-fungal liquid medication which stated "for cats",  an ear drop bottle and an enzyme-based shampoo. "Vet 1 had written in the case sheet - no sarcoptic or demodectic mites seen. She said my dog has malassezia inside the ears." Vet 1 had confirmed by staining.

"It is possible that your dog has malassezia, a yeast infection." I said. "Negative skin scrapings do not mean there are no scabies. After all, your friend's dog, the sibling of this dog, had scabies."

The following are the images I took of the friend's case scabies 4 weeks ago. The dog is a sibling of the presented case.

tpvets_logo.jpg (2726 bytes)5308 - 5309. Itchy and crusty ears. Scabies in the sibling of another owner, 4 weeks ago. Now fully cured. No images available as the owner did not come back for any review since the hairs have had grown back on the ear edges and there is no more scratching

"It is not possible as our dogs don't meet." the lady with the read eyes disagreed with my "instant diagnosis" and Vet 1 had stated that her dog does not suffer from mites due to one or more skin scraping done.

"Scabies can be transmitted by owners' hand. Did you touch her dog earlier?"

"Yes," she said.

"Any kiss and hugs?"

"Yes," she laughed. All puppies usually get kisses and hugs from lady owners.

"So your hands could have transmitted scabies mites to your own dog. When did you touch your friend's dog?"

"One to two months ago."

"How is the scabies dog now?" I asked the friend who had asked me  why Dr Vanessa was not present on this second visit. She wanted Dr Vanessa as her puppy was vaccinated by her, she told me. She came again in the morning, before 12 noon and Dr V worked from 12 noon to 8 pm on weekdays and that was why she missed seeing her.

I said to the friend, "Do you remember seeing one scabies mite under the microscope?"

"Yes," the friend said. "My dog is fully cured now. I complied with all your instructions of cleaning."

"Normally it will take 2 weeks and one injection to recover," I said.

"My dog recovered in 1 week as the hair grew (back on the ear edges)."

So, now I have to prove that this lady's dog has scabies. Actually Dr Jason was on duty on this Saturday. So I asked Dr Jason and Mr Min to do a few skin scrapings. "Make sure it is deeper into the skin. There is no need to use oil. A drop of water will do." So both took the dog to the back room and produced a skin scraping.

I examined the skin scraping from Min and put the slide under the microscope. I scanned the hairs and cell debris. There was no scabies mites.

"I can't find any mite," I said to the lady owner. "I will have to do a deeper skin scraping to look for the mites." The lady cringed at the thought of drawing more blood from the ear edge skin scraping as she could feel the pain of her young dog. She had diagnosed "allergy" as her dog had scratched herself violently.

Dr Jason shook his head when I told him there was no mites seen from the ear crust. "No mites, no scabies." Simple as that. "Perhaps, the ear crusting could be ear trauma," I speculated. There was evidence and I was quite sure that the crusty ear spot was due to the burrowing of the scabies mites. However, no smoke without fire. No scabies diagnosis without scabies mites. I was at the dead end. No light at the end of the tunnel.

Yet the clinical signs of intense itchiness of the face, cheeks and ears over one and a half weeks meant there were some mites burrowing deep inside the skin. The elbows and hocks were reddish and hairless. The backside had several ringworm like patches (see images above). So, there was some pathogens attacking the skin. Malassezia and ringworm medication were given for the past 10 days and yet there was no improvement in the skin disease.

"Is the anti-fungal medication bottle that states 'for cats' safe for use in dogs?" the lady with red eyes asked me.

"Well, the liquid medication in the bottle is not produced by the drug company for dogs. It is marketed for cats. However, the dog can take the medication if given appropriate doses."

The problem is that this young female dog was still scratching intensely and was wild last night, upsetting the lady whose red eyes could be due to emotions rather than infections, in retrospect.

Knowing that the lady would prefer no more skin scraping, I had  second thoughts of traumatising her. The dog is family and any deep skin scraping would be brutal in her opinion. Yet talk is cheap. Show and tell is the best policy.

I reviewed the slide again instead of doing another skin scraping. Hoping against hope.  I scanned mm by mm. And suddenly, the Gods were kind to me. A fat looking squarish mite was moving his six claws under the slide! "Come and see the scabies mite," I asked the lady with the red eyes.

The owner saw it under the higher power. I got the power to the lower one and the mite was distinctly seen by the lady. It was alive and punching its claws outwards.

So, there was proof of scabies.

No smoke with fire. No scabies without scabies mites. I could find only one. But that was sufficient evidence as it is sometimes very difficult to find them. Unless the skin scraping is deeper as the mites burrow under the skin. I did not do the skin scraping myself and this case was part of the "trust and audit" case for my staff.

Once the diagnosis was there, the owner had confidence in the veterinary surgeon's competence. This is a tough world as Singaporeans are now highly educated and well informed.

The treatment is a simple injection of ivermectin subcutaneous. Sometimes two injections are needed, but usually one is sufficient if the dosage is just correct.

However, this sibling seemed to have some systemic disease like hormonal disorder as the whole body below the chest was affected by skin wounds and infections.

"I need a blood test to check on the health of this dog," I advised. The owner consented. This may not be a simple case of scabies and malassezia. But it may be related to a poor immune system or hormonal imbalance like an early stage of "polycystic ovary syndrome (PCOS)." Many doctors will diagnose a young lady putting on weight as having eaten too much but she may be suffering from PCOS.

So in this case, the dog's generalised skin disease could be due to a poor immune system as she had been on anti-ringworm medication for the past one and a half weeks with no response. 

It is hard to say at this stage as more tests for hormones can be expensive. Two siblings. One had scabies only on the ear edges. This one had the whole body infested with skin disease. Why?  

I phoned the owner today, May 16, 2012 to enquire about the female shih tzu, one year old with only one scabies mite shown in the microscope to her. The friend had the sibling but its ears were the only area affected.

"A scratch or two, short while in the morning and evening," she said. "Not like the furious scratching earlier. Do I have to consult you 2 weeks later?"

"No, if the hairs grow back," I said. "Some scabies dog need a 2nd injection 2 weeks later. Wait and see." I was glad that the ivermectin injection had worked and the owner had bathed the dog's skin lesions thoroughly. It was very stressful for her to see her young dog scratching for weeks."

Blood test was taken on May 14, 2012 as the dog had generalised chronic skin infections.

"Normal blood test results, except for increased liver enzymes," my associate vet told me.

RESULTS are normal for the total white cell count but if you analyse the profile of the cell types, you will see that this dog has a chronic infection as evident by increase in monocytes to 11% and eosinophils to 8%. Normally the values are below 2%.

Total WCC  11.9 (6-17) is normal but the monocytes and eosinophils are higher than normal


Neutrophils  71%   8.47
Lymphocytes 10%  1.15
Monocytes    11%*    1.27
Eosinophils   8%* 0.96
Basophils      0.3%  0.04

SGPT/ALT     95  (<59)
SGOT/AST   158  (<81)
Could there be other medications given by the owner's family members affecting the liver functions?

Did the owner's mother use medication on the skin over the past months, affecting the liver?

Overall, this was a chronic skin disease for a young dog. Was it ringworm first, yeasts inside the ears and then scabies spreading from ear edges to face and paws? Or was there scabies in the first place? It is hard to say. Blood tests can be useful and in this case, there was no bacterial infection as Vet 1 had given the antibiotics. Antibiotics don't kill scabies mites and that was why the dog kept being itchy and worrying the lady with reddened eyes.  

Skin diseases are hard to diagnose. Execute evidence-based medicine. Always show and tell. This provides confidence to the owner. Unfortunately, it was not possible to find more than one scabies mites in both of the dogs.

Other than the possibility of re-infestation, my hypothesis is that the two dogs were treated earlier by the breeder or pet shop operator or animal shelter, as the two owners had adopted them when they are over 6 months of age. In the earlier treatment, the dosage of the anti-mite medication was insufficient to eliminate all the mites but sufficient to make skin scrapings negative.  This was a case of no smoke without fire. The fire is the "scabies mite." I was fortunate in finding only one scabies mite in each of the two siblings. Whether one or more, the clinical outcome of freedom from skin scratching is what the owner wants.

Performance counts although evidence is important. 

  pug 7 months, injuries serious, deep central ulcerative keratitis, leakage aqueous toapayohvets singapore


To make an appointment: e-mail
tel: +65 9668-6469, 6254-3326 
Be Kind To Pets
Veterinary Education
Project 2010-0129
tpvets_logo.jpg (2726 bytes)Toa Payoh Vets
Clinical Research

Copyright Asiahomes
All rights reserved. Revised: May 21, 2012

Toa Payoh Vets