Haircoat Problems in Dogs



Question: I have a beagle mix whose hair has been comming out by the hands full for the last 6 mos. We brush him often and we get gobs of hair off him. The skin is very flacky under his hair the hair loss is the worst on his back from the neck area to his tail. Some of the hair did not grow back and the skin is very dark. We use advantage for flea control. A thyroid test was negative. This problem seemed to come on after a cortizone shot was given when he was chewing his front paw to the bone. The paw cleared uand then the hair loss problem began. He also scratches his rump on the furniture. I have read your article on seasonal flank alopecia and it doesn't appear to be the same thing. Thank you for making your web site available.

Answer: Harry-

Hairloss that occurs on the top of the dog and forms a triangle of hairloss, with the widest part of the triangle at the base of the tail and the point somewhere between the base of the tail and the shoulder blades, is usually due to flea bite or mosquito bite hypersensitivity. Imidocloprid (Advantage Rx) is a very good flea control product, so it seems somewhat unlikely that flea bite allergy is the problem, unless you live in a place where your beagle is exposed to new fleas on a continual basis or unless there is a problem with the use of the product, such as too frequent bathing, application of the wrong size of the medication or giving it orally instead of applying it topically (yes, this last one is based on an experience at our practice, so I know it can happen).

There are some conditions that can resemble flea allergy, including hypersensitivity to anal sac secretions, food allergy and sometimes inhalant allergies.

Almost all allergic conditions respond to corticosteroids, so it is odd that the problems seemed to get worse after the injection. However, there are times when a secondary bacterial infection is present and a cortisone injection makes the situation a lot worse, instead of better. This may be what happened in your beagle's case.

There are also times when the hair loss occurs due to hormonal disease. These disorders are more common in older dogs, usually six years of age or older. Hypothyroidism is the most common hormonal disorder leading to skin problems so it made sense to check for that first. The next most common problem is hyperadrenocorticism (Cushing's disease, HAC). Since this is a disorder in which high natural cortisol levels are causing the hair loss and skin irritation (if these signs are present), giving additional cortisone might make the situation worse. I can't actually recall a case in which this happened, though --- and just like most vets, I have given a dog cortisone based on clinical signs resembling flea allergy that eventually turned out to be Cushing's disease.

The other thing that sometimes resembles flea allergy is mange. In my area Sarcoptic mange would be most likely to cause these problems but in some areas of the country another mite, cheyletiella, might also cause similar problems. Sarcoptic mange is very itchy and it can be really hard to find the mites. So it is sometimes necessary just to treat for the mites in order to figure out if they are there.

It can take several tries and several different test procedures to isolate the cause of a skin condition. If your vet is unable to resolve the problem after several visits, it might be a good idea to ask for referral to a veterinary dermatologist. Most of the time, if you work with your vet and you both are patient, skin problems can be resolved.

Mike Richards, DVM 9/19/2000

Seasonal flank alopecia or hormonal disease possible

Question: Dear Dr. Richards, My six year old female Bedlington Terrier, Chessie, has thinning hair on the trunk of her body and her skin has become very dark. Her thyroid tests are normal. My vet thinks that there is a possiblity that she has a melatonin deficiency. He said it is a rather rare condition and he will do some research on it to decide for sure. In the meantime, could you give me some information on melatonin deficiency?

Many thanks for your help.

I really enjoy your newsletter!

Best wishes, M.R.

Answer: M.R.-

I can't find any references to melatonin deficiency in dogs. There is a condition, known as "seasonal flank alopecia" which occurs in some breeds. I haven't seen a reference to Bedlington terriers but the list of affected breeds seems to be growing, so it doesn't seem out of the question that it could occur in this breed, too.

This condition usually is seasonal and occurs in some dogs during the colder months and other dogs during the warmer months. It should clear up at least part of the year. There is hairloss on the flanks and the skin does get darker. We have seen this condition in a couple of boxers in our practice. The usual recommendation is not to treat this condition the first time it occurs because sometimes it doesn't come back. If it does come back the next time the season that is associated with it rolls around, then it might be worth trying melatonin. The references to using melatonin recommend an injectable version of melatonin and I have no idea if oral melatonin would work as well, or at all.

The other thing to consider is other hormonal disease. Hyperadrenocortism is a fairly common cause of hairloss and increased skin pigmentation and there are other hormonal disorders that can cause similar signs. It seems reasonable to me to try to rule out this condition prior to looking for one that is more rare. Your vet may have already done this or may have good reason not to consider hyperadrenocorticism but it would be worth asking about it.

Hope this helps some. If your vet isn't referring to seasonal flank alopecia, I can try to search the literature databases again for you.

Mike Richards, DVM 11/17/99

Hair loss - Cushing's disease or not?

Q: I just ordered vetdigest. i am so happy i found this website because after all the problems i have been going through with my 10 year old poodle casey, i finally feel like i can trully trust your advice. my poodle for the past 5 years has lost the hair on his back and sides in march and the hair regrows to its regular thickness in september. i was told by my vet that casey had a thyriod problem and if we treated the hair loss it would affect his liver. the vet reassured me that the thyroid condition was no threat to his health if left untreated. in march 1998 it all started, casey was diagnosed with a slipped disc. i wasn't satisfied with my vets treatment so i went to get a second opinion. this is when the hair loss was questioned. my new vet wanted to run various test to see if cushings was present due to the hair loss. casey doesn't have any other symptoms and its very hard for me still almost a year later to believe that this is what he has. casey has always urinated alot since he was a puppy. i take him for walks and he has to urinate on basically every tree and pole we pass, i thought this was just the male territorial thing in him (and i still do). casey is 10 and still has just as much energy as he did when he was 2. he has no enlarged abdomen and does not drink abnormal amounts of water. but yet my vet says that the tests show cushings disease. casey is now on the maintence dosage of a 1/4 tablet(500mg) every 6 days. now that casey has been on lysodren for approx 8 months he still has not regrown any hair. i thought maybe the lysodren is prohibiting the hair growth because before being diagnosed, like clock work his hair grows back in september. my vet said that within 2 months on maintenance of lysodren his hair would start growing. still casey shows no signs but the hair loss and the small amounts of urination on everything . these symptoms have been for as long as i can remember. do you think casey has had cushings disease for more than 5 years or could this be a misdiagnosis. thank you very much in taking the time to ease my worries about this situation

sincerely, jaime

A: Jaime-

Your question is hard to answer. I think that there is a chance that Casey has a condition known as "seasonal alopecia", which is hair loss on the flanks that usually starts in the spring and ends in June or July. It has been recognized in several breeds, including miniature poodles. This condition is not very common but it seems to fit the symptoms.

It is possible to diagnose hypothyroidism more accurately at this time was possible in the past few years. The free T4 level measured by equilibrium dialysis, especially when combined with a TSH level test, is pretty accurate at determining if hypothyroidism is present. I do not know of a liver problem related to treating for hypothyroidism so I am not sure what the concern was there. It is possible that your dog does have this problem but it seems equally as likely that he does not.

Cushing's disease can occur without many of the normal symptoms. I am assuming that laboratory testing supported this diagnosis? Testing for Cushing's disease (hyperadrenocorticism) is usually done by low dose dexamethasone response testing, in which a blood test for cortisol is drawn around 8 AM and then an injection of dexamethasone is given. Cortisol samples are taken again at 6 hrs and 8 hrs after the injection. If a dog has Cushing's disease the cortisol levels are not suppressed by the injection. There are other tests for this condition, though. Checking to see what test was run and what the results were might be reassuring.

It may be a good idea to consider getting a third opinion, too. If you do decide this is a good idea it would be best to ask your vet to refer you to an internal medicine specialist who can review the history and lab data and help make an objective decision about the need for retesting or adjustments in treatment.

Hope this helps.

Mike Richards, DVM

Hair loss under collar

Q: We recently adopted a mixed breed dog from the humane society. Age about 18 months. She seems to be in good health, however, we recently noticed that she has a large area under her neck where she is losing hair (possibly from her collar?). Any advice would be greatly appreciated. Thanks. Sandy

A: Sandy- It sometimes helps to get a different collar -- some dogs lose hair because their hair gets caught in the collar and pulled out and other dogs are sensitive to the fit of a particular collar or allergic to the substance it is made of (or at least it seems that way). If there is any evidence of skin disease, such as scabbing, redness, bumps or sores it would be best to see your vet first and worry about changing collars later. The rubbing of the collar tends to make skin disease show up at its earliest right under the collar in some dogs.

Mike Richards, DVM

Bald spot

Q: Have you any idea why a dog would lose fur between her shoulder blades to the point that the area (now about the size of a loonie, or the end joint of an average thumb) is completely bald as a babies bottom. Might this be caused by food allergies, or could this be a fungal infection? I've changed her food to Nutro Max (naturally preserved with vitamin E) and am now making soft food (rice/ ground beef and garlic) in the hopes that this might prevent more fur loss. She (a 10 year-old corgi/collie cross) also has lots of dry spots all over her body by mostly on her back legs where the fur can be picked off easily, but not to the point of baldness. We recently moved to Alberta from Ontario and I originally attributed this to dryer air. She's also a neurotic little thing and blind (spontaneous retinal detachment at the age of 4). Could this be a nervous condition? Her thyroid is find, and she doesn't suffer from hypertension. Any ideas?? Thanks. Vera

A: Vera- I think it is possible that allergies or an infectious agent such as ringworm could cause hairloss in a small spot like this but I would expect it to spread from that point -- especially with allergies. A contact allergy might result in a spot similar to the one you describe but the only thing I can think of that is likely to contact this area alone are the topical flea control products such as Advantage (tm), Frontline (tm) and ProTICall (tm). This is supposed to be an occasional problem with Advantage application and we have seen itchiness after application of ProTICall as well. Some dogs develop areas of hairloss over vaccination sites. This is supposed to be a problem with Bichons more frequently than other breeds. I have seen this problem and the skin appeared irritated and thickened at the site in addition to the hairloss.

I think that a skin biopsy could be very informative if the problem persists. You might want to discuss this option with your vet.

Mike Richards, DVM

Bald spot on tail

Q: I have a 7 month old female Dachsund. She is a perfectly healthy dog, who loves to play and loves people. Of course we adore the dog. She had developed a skin problem on her tail. She is slowly losing her hair in a spot about 1" long by about 1/4" wide. There are no scabs, sores, irritated spots or anything of this nature. Just a tiny bald spot with the continued lost of hair. I remeber when she was but 6 weeks old there was a tiny bald spot on her tail then. I figured it was just a place where hair would eventually grow as she was just a puppy. Not true. The vets here cannot figure out what it is. Can you help.?

A: There is a gland along the top of the tail at about the junction of the first and middle thirds of the tail. Some dogs lose the hair over this gland. I know of nothing that will consistently help with this condition. That is one possible cause of the hair loss. Almost all other causes of hair loss in dogs can affect just the tail in some cases, so it is important to eliminate mites, anal sac irritation, flea allergy, flea infestation, etc. I'm sure your vets have probably been eliminating those problems as they went along in examining her.

If you wish to have a second opinion from a specialist, there are veterinary dermatologists and your vet can probably arrange to refer you puppy to one. Good luck with this.

Mike Richards, DVM

Bilaterally symetric hairloss

Q: Our 8 year old female spayed Australian Shephard lives with us since four years in South Florida. We have always let her do her morning and evening elimination on the vacant grassy lot next door (unleashed). We also walk her on the street (with leash). She marks her territory in the lot and often rolls to leave her scent. For the first time this year, we observed hairloss on both sides in large patches leaving kind of white punctate bare skin. She also scratches these areas. Also, her coat seems drier than before. We will undertake more agressive flea control (today I noticed one flea near a scab near her anus). We are giving you a complicated question here but I am sure you encounter similar questions.....should we be doing any more?....Mike and Irwin

A: Mike and Irwin- Bilaterally symmetric hairloss without itching is indicative of hormonal disease, such as hypothyroidism or Cushing's disease. When itching is present it is necessary to consider the hormonal diseases and other conditions that can cause hairloss such as allergies and flea infestation. It would be a good idea to consider a visit to your vet to sort all this out if the problem continues.

Mike Richards, DVM

Seasonal hairloss

Q: I have a three year old part Shar-Pei and Lab mix. Every spring he developes a problem with his hair. He losses all the hair on his back legs on on his back. He digs and scratches himself raw. He also developes a terrible odor about him. The vet says that I can use any kind of human shampoo on him, it does not help. He does not have fleas, at least I do not see any on him. His skin also tends to be quite dry and flaky. I feed him lamb and rice dog food. Is there anything that I can do for him to help him with his skin condition?

A: Debbie- Since your dog's problem is seasonal there is a very good chance that allergies are the problem. Shar peis are very prone to allergies so that makes it more likely, too. When dealing with allergies, it is extremely important to limit any possible source of itching. Please check the list of itch control suggestions on our "Top Ten Questions" page or in the skin disease section of the dog information section.

It is best to assume that fleas are present, even if you do not see them, when you have an allergic dog. Use one of the new flea control medications, Frontline (rx), Advantage (Rx) or Program (Rx) to control fleas. In allergic dogs, I tend to lean towards using Frontline or Advantage since adult fleas are the major problem but I own an allergic dog and I use both Frontline and Program because I can keep her comfortable if I can totally eliminate fleas.

Consider seeking the help of a veterinary dermatologist or allergist to ensure that this is in fact an allergic condition and to formulate a plan to deal with it. Owners of young dogs affected with allergies should strongly consider trying hyposensitization ( injections of small amounts of the substances causing allergies to make the dog's body less reactive to them). This does not work for all dogs but it is a much better approach than using corticosteroids to control the itching, when it does work.

If going to a dermatologist isn't possible your vet can do the basic testing to ensure that problems like demodectic mange, sarcoptic mange, skin infections and immune mediated disease are not present and then provide medications that will help with the itching. Judicious use of corticosteroids in this situation is justified. There is a lot to be said for comfort and relief from the suffering of constant itching. Most dogs do not have serious side effects from the use of corticosteroids and they should not be denied its benefits because there is a small risk of problems which can usually be resolved by withdrawing the medication if they occur.

Mike Richards, DVM

Seasonal flank alopecia in Boxer

Q: Dr. Mike: I could use your advise. I have a 3 year old Fawn Boxer. She is the most fantastic dog I've ever met. She has had all of her shots to date. See's happy and seems healthy. However every spring just as the weather is changing, she loses the fur off of her flanks on both sides. The area is always the same, just ahead of her hips. The first year it was only a small area and recovered quickly with no intervention. The second year it got bigger and lasted longer. We went to our Vet he did blood tests. He stated that her thyroid tested ok. He thought she should be on a topical solution of Humilac (we rubbed it in twice a day.). A few weeks went by and no real change. We went back he stated her hormone levels were ok but since she was spayed he wanted to try estrogen. We tried that for a few weeks and no change. So we stopped it. A few weeks later the hair regrew. This spring like clockwork it's back. Bigger and badder then ever. She is not sensitive in the bald area there are no bumps, seeping areas or smell. THe skin it soft and dark. We tried a new Vet that some friends recommended. He said to try "PET-F.A. LIQUID" in her food. We tried that for over a month and no change. She is active but does not seem as active as a friend of mines Boxer. THe Dr. said she was over weight and we've slowly switched her diet over from Innopet Veterinarian Formula to Purina's Fit and Trim. She is a fussy eater and it has always been hard to find a food she will eat readily. She really digs into the Fit and Trim. She is about 50 lbs and get 4 1/2 cups a day. She has regular bowel and urinary cycles. We use to bathe her weekly we backed off to once a month an she gets washed with a natural orange formula for dogs and her final rinse is with 1tsp of Alpha Keri in one quart of water. When I say final I mean after all of the soap is off of her with the water spray then she gets the Alpha-Keri rinse. We only did this rinse once so far it was recommended by the Vet. It leaves her coat very soft and shinny. Her patches are starting to fill in now. But is there anything you can suggest we can do next year to prevent it from reoccurring? Thank you for your time. W.

A: Boxers are prone to hair loss on the flanks and it is often a seasonal thing. So it goes under the name "seasonal flank alopecia". I am not sure why it occurs but it is most common in spayed female boxers and Airedale terriers. Skin biopsies are helpful in confirming this condition and it is easy to confuse with several other problems including demodectic mange, inhalant allergies, endocrine disorders such as hyperadrenocorticism (Cushing's disease) and hypothyroidism.

Your vets may be uncomfortable diagnosing this since I don't think it is common enough to be seen often in general veterinary practices. If there is any question about it referral to a veterinary dermatologist may be helpful. Recently there has been some interest in treating this with melatonin injections (seems to require injections) but I am not sure how successful this has been.

Mike Richards, DVM


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...