Nasal Solar Dermatitis in Dogs

Affecting the tip of the nose, eyes and surrounding areas of your dog, nasal solar dermatitis occurs most often in Collies, Shetland Sheepdogs, German Shepherds and mixed breeds that are similar. While the exact cause of the of the condition is unclear, exposure to sunlight is a factor. Nasal solar dermatitis may sometimes be a misdiagnosis for the nasal dermatoses that dogs may experience from numerous other diseases.

Nasal solar dermatitis, also called collie nose, is a congenital problem in dogs that results in an abnormal response of their skin to sunlight.

In a true case of nasal solar dermatitis, the nonpigmented areas of the tip of your dog’s nose will be the first to be affected. The bridge of his nose may also become swollen and in some cases an ulceration may occur. Inflammation may gradually spread up the bridge of your dog’s nose, working its way to the periorbital tissue. This may lead to inflammation of your dog’s eyelids (and possible conjunctivitis). Areas of peeling, scaling, and bleeding on or around the nose of your dog will be present. Lesions are typically worse in the summer, though the reflection of the sun off of snow can be problematic for your dog as well. 

As the condition worsens, the ulceration your dog is experiencing can lead to the epidermis, dermis, and cartilage to disappear. In advanced cases, tumors may develop. While symptoms are typically present on or around the nose, sun damage can also be present on your dog’s trunk or limbs.

• Ulceration on the nose
• Bleeding on the nose
• Skin irritation and lesions
• Inflammation of the eyes
• Development of tumors

Types 

Nasal solar dermatitis is often a misdiagnosis of a nasal dermatoses that has been caused by another disease. For example, in systemic and discoid lupus, as well as pemphigus and cutaneous lymphoma, the tip of your dog’s nose may be depigmented, red and possibly ulcerated. In pyoderma, dermatophytosis and demodicosis, the part of the muzzle that has hair will be impacted. Systemic lupus erythematosus and pemphigus may affect the entire muzzle through ulceration or crusting.

Nasal solar dermatitis is a congenital condition. While the exact cause is not clear, exposure to sunlight causes the condition to worsen. Symptoms will usually be worse over the summer and/or with greater sun exposure. There are numerous diseases that can lead to nasal dermatoses in your dog. These include:

• Systemic lupus erythematosus
• Pemphigus
• Discoid Lupus
• Pyoderma
• Dermatophytosis
• Demodicosis
• Cutaneous lymphoma

Nasal dermatoses are different than nasal solar dermatitis. When your veterinarian is examining your dog, he will look to determine whether your dog has nasal solar dermatitis or if his symptoms are a result of an underlying condition like those mentioned above.

As other conditions can cause similar symptoms to those of true nasal solar dermatitis, your veterinarian will want to first confirm your dog’s diagnosis. After conducting a physical examination and asking you for information on the symptoms you have noticed and when you began noticing them, your veterinarian may conduct the following:

• Skin scrapings (for further examination)
• Bacterial and fungal cultures
• Biopsies for histopathology and immunologic testing

Should you veterinarian think your dog may be suffering from systemic lupus erythematosus, he may draw blood for an antinuclear antibody test.

If your dog is diagnosed with nasal solar dermatitis, your veterinarian may recommend a topical corticosteroid lotion (for example betamethasone valerate, 0.1%). This will help reduce inflammation. Corticosteroids may also be recommended, as administration of these will help to decrease the inflammation quickly. If the lesions involve your dog’s mouth, systemic administration may be preferable. Should your dog have developed a secondary bacterial infection, antibiotics will be given.

Your veterinarian will likely recommend that you restrict your dog’s exposure to sunlight; when your dog is out in the sun, a sunscreen will be helpful and it is recommended that you apply it two times a day. It is best to get a recommendation from your veterinarian on what sunscreen to use as not all that are made for people are safe for dogs.

In order to decrease sun damage, beta-carotene may be recommended by your veterinarian. Retinoids (for example synthetic Vitamin A analogues) taken orally may also help. Retinoids do have potential side effects, so your veterinarian will likely want to monitor your dog closely should they be a part of his treatment.

Long term treatment will depend on the degree to which your dog’s exposure to sunlight can be limited, as well as how he does when exposure is reduced. One effective long-term treatment is tattooing with black ink the area where the pigment is not present. This should only be considered once the inflammation is under control. Touch-ups are typically required and this treatment is best early in the course of mild cases of the disease.

The number of and time between follow up appointments will be dependent upon your dog’s condition. Your veterinarian will likely want to see how your dog is responding to treatment and adjust medication as necessary. As mentioned, a key component of managing nasal solar dermatitis in your dog is to reduce his exposure to the sun. Keeping your dog indoors, particularly during the hours between 9am and 3pm will be important for managing his condition. Ongoing management will be required for those experiencing nasal solar dermatitis.