Dog's nose: origin of acquired depigmentation and nose problems

My dog's nose is getting depigmented, why ? Does he suffer from a dietary deficiency?

A) Nose depigmentation, only one symptom observed

It is the most difficult case to explain : let's see different possible hypothesis.

1) Vitiligo

• Inherited disease, but not present at birth : it usually appears by the age of 2 years old. It is the "pink nose" syndrom, that is mostly ssen in followin breeds : German Shepherd, German Pointer, Belgian Shepherd, Newfoundland, Doberman, Rottweiler, Bobtail ...
• Mechanism : lack of pigment (melanin ), due to a non-explained destruction of the melanin-forming cells (melanocytes).
• The evolution is extremely variable : the depigmentation can lay over the whole nose, or disappear. Usually, the lesions do not become ulcerated, except in case of prolonged exposition to the sun.

2) Discoïd lupus

• Autoimmune disease, rather frequent in dogs : it is the only one autoimmune disease who does not exhibit any other clinical sign. It occurs mainly between 3 and 8 years old ; predisposed breeds are German Shepherd and Colley.
• Mechanism : destruction of cutaneous cells who contain melanin (keratinocytes ).
• Evolution : almost always towards ulceration, formation of crusty lesions on the nose, the bridge of the nose, eyelids, sometimes even on the pads ... UV rays have a very worsening effect.

3) Sunburns

In some breeds (Colley, Shetland ...), nose depigmentation can follow prolonged exposition to strong sun radiations.

4) Idiopathic depigmentation of the nose

The most frequent case however, remains incomplete and/or cyclic depigmentation that occurs in adult dogs with black nose: unhappily, the origin is still unknown.
All these hypothesis can be confirmed through histologic examinations : depigmented nose-tissue has to be sampled (biopsy) and microscopically observed.

There is not much to do in those cases : the most important thing is to protect depigmented areas from the sun with protective creams ("total screen"), when sun radiations are specially aggressive.

B) depigmentation with other clinical signs

Diseases dépigmentation characteristics Other clinical signs auto-immune dermatosis lupus, pemphigus nose + bridge of the nose, lips, eyelids ulceration fever, polyarthritis Leishmaniasis ailes du nez, coussinets ulcération atteinte de l'état général, augmentation du volume des ganglions uveo-cutaneous syndrom nose + other mucosa ocular symptoms Mycosis nose + bridge of the nose, face ... - Aspergillosis wings of the nostril +/- érosion chronic sinusitis fongoïd mycosis delayed ulcération lesions in plagues on the whole body epidermoïde carcinoma destruction of the nose tissue -

In case of persistent lesion on the nose, a veterinary examination is necessary. All these affections can be diagnosed by collecting the case history, clinical examination, and complementary examinations (biopsy, serology, mycology).

On a nutritional aspect, pigmentation mechanism requires the following nutrients :

• amino-acids : tyrosine, tryptophane
• trace-elements : iron, copper
• vitamins : folic acid, pantothenic acid.

ROYAL CANIN products contain a large amount of these nutrients and no deficiency is to fear. On the contrary, secondary copper deficiency has been described in dogs who received zinc in excess : the ratio zinc : copper must stay under 10 : 1, even if zinc supplementation is distributed.

Even if sometimes, pigmentation comes back after a change of food, it does not mean anything : depigmentation is a cyclic phenomenon, likely to appear and disappear at any time.

Donated by the Borg Cardona and Co. Ltd. visit Borg Cardona website