Depigmentation of nose
Question: Hello Dr Mike,
.. I asked this question to you before but you did not answer it (although you did answer other questions!). I'm concerned because my dog has been losing the black pigment on her nose for over the last year. She's got a spot that's around 5mm in diameter that has turned from black to grey. She may have hypothyroidism as you already know and I will probably start her on treatment a few months after her next heat.
You have written to me that in your personal experience you have never noticed a dog's pigment to come back after thyroid treatment. But I have read that all symptoms due to hypothyroidism are reversible through treatment. Is this not accurate?
I'm wondering if you could refer me to any research articles regarding loss of nose pigment due to hypothyroidism. I'm wondering how did they determine the loss of pigment was due to hypothyroidism if the pigment did not come back after treatment?
If you could provide an explanation I would appreciate it.
Sometimes I get hung up on one part of a question and then I have a hard time writing an answer to it. This is the case with your question. What I was hung up about is that I am nearly certain that I have seen references to hypothyroidism causing depigmentation of the nose but I haven't been able to go back and find a reference that says this. So either I am mistaken or perhaps the information was inaccurate and has not been repeated in the more recent literature due to that.
The various causes of loss of pigmentation of the nasal planum (the usually black portion of the nose) that I can find good references for are:
1) Dudley nose -- loss of pigment seen in a number of breeds for unknown reasons in which the nose is black when dogs are young but fades to brown or sometimes even white as the dog ages.
2) A transient form of the above condition may exist or it may be something else, but some dogs do lose some pigment and then recover the normal coloring of their nose over time.
3) Labradors, Golden retrievers, Bernese Mountain dogs and Siberian huskies may have seasonal variation in the color of the nasal planum, usually lighter in the winter and darker in the summer. The cause of this is not known, either. Some vets refer to this as "snow nose".
4) Vitiligo can cause loss of pigment of the nose and it may also be part of a syndrome of immune mediated disease in which hypothyroidism also occurs, so perhaps this is the link to loss of color of the nose and hypothyroidism but if it is, the hypothyroidism is thought to occur after another disorder causes the color change. Dogs with vitiligo normally have development of patches of white hair or white hairs scattered in the hair coat. I don't think that loss of pigment in the nasal planum only is likely with this condition.
5) Contact dermatitis can cause loss of pigment in the nose -- some dogs are reported to be sensitive to the plastic that is found in some feeding bowls, for instance. Continual irritation of the nasal planum from a cause like this might lead to loss of pigment. Usually the lips are also are inflamed or may have pigment loss if they are dark, too.
6) We see dogs with discoid lupus and with phemphigus that have loss of pigment of the nasal planum, usually patchy but sometimes most of the planum is involved. There are also usually skin sores around the edges of the nasal planum, on the bridge of the nose, around the eyelids or places like that.
7) I have seen cats with squamous cell carcinoma lose the pigment in the nasal planum as an early sign. I am not sure that this same problem occurs in dogs but I wouldn't want to totally rule it out.
So the bottom line is that I can't answer your question about whether loss of nasal pigment due to hypothyroidism is reversible because I'm not sure that loss of nasal pigment is a sign of hypothyroidism at the present time, even though I am pretty sure that I too have heard that this happens sometimes.
Mike Richards, DVM 10/6/2001
Question: I'm a new subscriber. My 22 mo. old GSD has what's been referred to as "snow" or "winter" nose. He's lost the pigmentation in the middle of his nose, in a vertical stripe from the bottom of the nostrils to the top horizontal plane. It's about as wide as the space between his nostrils. Anyway, his mother has this problem, but it's only a very dark grey in this area, not light almost pink like Indy's is. His aunt's is also light - more like his is, but only halfway up.
I've tried LOTS of things to get this situation to correct itself. His breeder says it will change with the weather - summer tends to make it go darker, she says. I show him, and although he meets breed standards (nose must be predominantly black) I feel that if it were between him and another dog, the judge would put up the other dog b/c of Indy's nose. I have also been told to use vitamin B complex in conjunction with getting him out in the sun more. I have been doing this for almost a month with no change. I have also tried Kelp - used it for almost 3 months w/no change, but this was in the winter. I don't know how much influence the sunlight actually has on this condition. I have tried giving him cod liver oil too, thinking the Vitamin D would be helpful, and a handler told me to try giving him CASTOR OIL for 3 days - she'd heard at a handler's seminar that this would cure it. Well, it didn't. But my boy had some NICE stools! I've talked w/other GSD owners, and they have said it will get better - but I'd like to know if there's anything I can do to "help" it along. I also know that people have dyed their dog's noses for shows - I WON'T do that - I guess I'm just a stickler for ethics.
By the way, this condition came about at the end of October - he was playing with my bitch, and turned and hit his nose HARD against the corner of the bathroom vanity. He sneezed really hard several times, and I had to check to see that his nose was not broken. About 12 days after this, almost overnight, his nose turned this lighter shade. It hasn't been black since. I have talked to almost all the vets in this area - I live in a small town in South Dakota, where almost NO ONE shows dogs, and the vets do not concern themselves with these types of problems - it's just OH WELL, it's just an animal.
I'm hoping you can give me some insight into this situation. I would certainly appreciate it! Thank you for your time!
There are several conditions that lead to depigmentation of the nasal planum (the specialized skin around the nostrils that is usually black).
Some dogs have permanent depigmentation that occurs spontaneously and does not appear to be related to any underlying disease process. Dogs with this condition are sometimes referred to as having "Dudley noses". I have no idea why. In this situation, the nasal planum looks absolutely normal, other than being tan, pink or some other lighter color than it should be. There are no consistently successful treatments for this condition in the literature but this condition is not harmful to the dog.
Vitiligo occurs in some dog breeds (rotties, for example). This is depigmentation of patches of skin, leading to patches of white hair in haired areas and to pale skin in other areas. This can affect the nasal planum. It is not common in German shepherd dogs, as far as I know. There are no consistently successful treatments reported for this condition, either. Dogs with this problem should have sun-block applied to exposed non-pigmented areas of the skin when they are out in the sun.
Contact allergies can cause depigmentation of the nasal planum. The most common contact allergy to have this effect is an allergy to plastics. Dogs with contact allergies usually have some evidence of skin irritation as well as depigmentation (often along the lip margin) but it may be very subtle. It is worthwhile to try stainless steel or ceramic food and water bowls to see if changing types of bowls will help, if a dog with this problem usually eats or drinks out of a plastic bowl.
Some dogs lose pigment in the winter time and have pigment in the summer months. This condition is referred to as "winter nose". There are no consistently successful treatments for this condition, either. There are reports of occasional success using the types of treatments you have already tried, but truthfully I suspect that these are just spontaneous remissions of the condition. If I had show plans for a dog and could figure out a practical way to do it, I think I would have to try using one of the artificial sunlight type lamps (Chroma D50 or Growlights) to see if it would help, though. It makes sense that it might. Unfortunately, this may be a condition that is more related to thermal changes, that to sunlight, so there is also a good chance that wide spectrum lighting wouldn't help. Some veterinarians think that administration of Vitamin E may be helpful but has to be done continuously (400 U per day should be sufficient). There are no scientific studies that I am aware of that support this notion but it seems reasonably safe to try Vitamin E.
Phemphigus foliaceus is an immune mediated disorder that German shepherds are somewhat prone to. It usually causes inflamed skin or small sores, along with depigmentation. It doesn't sound like these lesions are present but it would still be worth looking carefully. Eyelid margins, interdigital spaces and ears are also commonly affected when this condition is present.
Hypothyroidism is reported to cause depigmentation occasionally. I think that this is a pretty uncommon problem to surface as the sole sign of hypothyroidism but that is the reason that kelp is reported to be helpful in a small number of dogs with nasal depigmentation. Kelp is high in iodine and may help with subtle hypothyroid conditions. It is extremely easy to misdiagnose hypothyroidism, so caution should be used in searching for this condition based on limited clinical signs.
I know this wasn't much help, really. Your local vets are probably not disinterested. They just don't have anything to offer you that is likely to work to correct the problem, so they are trying to point out that it doesn't affect the dog's health and that the dog probably doesn't care. None of which is very comforting when you have a goal, like winning shows, that depends on correction of the depigmentation.
Mike Richards, DVM 4/28/2000
Question: My reason for subscribing to vetinfo digest; My bichon-his name is Bobby-his nose is getting lighter in color. He is three years old. He seems fine otherwise. What do you think it could be.
There are a number of possible causes for depigmentation of the nose.
plastic or rubber food bowl contact allergy- some dogs are sensitive to plastics or rubber and their nose depigments due to contact with these substances
idiopathic nasal depigmentation - there are several forms of this, most commonly the nose turns brown or pink and stays that way, other dogs the depigmentation is variable and some dogs are reported to have depigmenation in the winter and normal pigment in the summer, a condition referred to as "snow nose". Permanent depigmentation is sometimes referred to as "Dudley nose". I have no idea why.
phemphigus can cause depigmentation of the nose. This is an immune mediated disease. It usually causes crusts on the nose and other places on the head where normal skin meets specialized skin, like the eyelid margins, ears and lips. It may spread to normal skin later in the disease. There are several forms of phemphigus.
discoid lupus causes similar lesions to phemphigus except that it often affects normal skin early in the disease. If there is nasal depigmentation with this disease it is likely that there will be ulceration of the nose. Sunlight makes discoid lupus lesions much worse and dogs with this may have terrible problems in the summer and very little problem in the winter
vitiligo causes white pigmentation of haired areas and pink discoloration of darker skin, like the nose. I think of this as a problem mostly in rottweilers but other breeds may be affected.
Some skin cancers can cause depigmentation of the nose.
If Bobby is young (less than three) and if this problem is confined to his nose and if there are is no scaliness, scabbiness or other sores associated with the condition there is a good chance that this is idiopathic nasal depigmentation. There is no need to treat this condition and am not aware of an effective treatment. However, if he eats from plastic or rubber food bowls or has a rubber or plastic water bowl, I think I'd change to something else. If he is young and there is scaling and crusting, I think I'd worry about discoid lupus, too.
If Bobby is older and there are no signs of other problems, this still might be idiopathic nasal depigmentation but it would be a good idea to keep a very close eye out for anything that might indicate skin cancer, such as scaling, erosions of the nasal planum, nose bleeds or decreased appetite.
Phemphigus tends to show up in middle aged dogs.
The best diagnostic test, if there is any reason to be concerned about diseases like phemphigus, lupus or skin cancer, is a biopsy of the nasal planum (the part that contains the nostrils and is usually black). It is best to submit the tissues to a pathologist with an interest in skin (a dermatophathologis), if possible.
Your vet can help determine if there is any need for additional testing. There are many instances in which the lack of clinical signs for anything other depigmentation make it perfectly reasonable just to do nothing.
I wish I had a solution to getting the nose to repigment. Sometimes that will happen, but you can't count on it.
Mike Richards, DVM 4/1/200
Q: Dear Dr. Richards,
My question to you this time is about a young (2yr) female greyhound. Though she had come "off the track" she had never been raced, for the strange reason that she is a "Blue". Is that really an indicator of poor lung capacity? She appears to be in spectacular good health now. Her only problem is that nose. I've heard that blue dogs tend to suffer from pigment problems but Tawny (that's her name) has nice dark pigment throughout. Only her eyes are gold colored. The nose has absolutely no pigment at all. It is pink and it tends to get crusty and to crack and bleed. Treating her with sunscreen lotions, or topical medication seems to do nothing at all. She simply licks it off. Vitamin E, I guess doesn't hurt, but the nose is still the same. Now with the cold weather it is actually worse than ever. Do you think it is simply a lack of pigment to the area, or could it be something else? It is just so very specific to the nose leather. It ends abruptly where the hair begins. Are there any medications that could be taken internally to alleviate such a problem?
Thanks again. Have a wonderful holiday and a great year.
Blue coat coloring in some dog breeds is associated with skin disease, usually hair loss that is not responsive to treatment. I have not heard of an association between blue coloring and decreased lung capacity but I can't be sure that there isn't one.
The problem with Tawny's nose could be simply lack of pigment as that problem does occur in several dog breeds. The only problem is that the pigment loss in those cases shouldn't lead to sores or cracking of the nasal planum (the area of the nose that is composed of specialized skin). An immune mediated disorder such as phemphigus or discoid lupus could lead to the signs that you have been seeing. These conditions are not usually responsive to treatment with sun blockers, although there may be some benefit when discoid lupus is present because solar irritation can occur with that condition (it gets worse with exposure to sunlight). The only way to be sure if one of these conditions is present is to biopsy the affected area and have the biopsy samples examined by a pathologist who is competent at discerning problems in the skin. If the problem is relatively minor it may not be worth going to that much trouble to find out what is going on. If the problem is causing Tawny pain or discomfort then it would be worth pursuing a diagnose, probably. Both conditions respond reasonably well to treatment. Both conditions usually affect more than just the nasal planum, eventually. If you see the problem spreading to other places on her face, such as the eyelids or ears there is more reason to consider pursuing a diagnosis, as well.
Hope this helps some.
Mike Richards, DVM
Q: Dear Dr. Mike, After reading some of the questions submitted to you I hope that I am able to describe my dog's condition. My little girl Chelzy, a three year old Boxer, recently began exhibiting swelling around the front of her lips. Shortly thereafter, the swelling gave way to pink pigmentation which now seems to have propagated to her nose as well. My Vet was not quite sure what was causing this. He prescribed antibiotics (I don't have the names at hand) and the swelling seems less severe, however, the pinkness continues to expand. I hope that this brief description allows you to provide some insight as to the possible cause and/or treatment. I would be happy to provide additional information if necessary. Thank you in advance for your attention.
A: Depigmentation of the nose occurs in several breeds in which no known cause of the problem exists. I have not seen a reference to this in boxers but it would not surprise me if it occurred in them as well. However, there are also several immune mediated disorders that can lead to depigmentation of the lips and nose, usually accompanied by skin sores. Since you saw some swelling with this it seems like it might be worthwhile to check into those conditions. This would be especially true if there are small skin sores or blisters associated with this or if you notice problems anywhere else on her skin. The immune mediated disorders include discoid lupus, systemic lupus erythematosus and the phemphigus complex diseases. These usually have to be diagnosed by biopsy of the affected area. Systemic lupus may also have a positive anti-nuclear antibody (ANA) blood test.
Depending on how much this seems to be affecting your dog, you may want to ask your vet about biospsy of the affected areas or referral to a veterinary dermatologist to try to pursue a diagnosis. There is a boxed off statement in Muller, Kirk and Scott's text "Small Animal Dermatology" relating to nasal depigmentation problems. It says "Nasal depigmentation may be a diagnostic dilemma". Your vet is not alone in wondering how to go about figuring out what is causing this problem.
Mike Richards, DVMLast edited 08/30/02
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...