Disorders Affecting Skin Color In Dogs
Abnormalities affecting the skin color can either be acquired or hereditary. Coat colour and skin disorders are related in some cases, as described in the hereditary hair loss section.
Dogs rarely suffer from albinism. Pink or pale irises and visual defects are the true signs of albinism, and it is quite different from excessive white spotting. In both of these cases, the animal affected can easily get skin cancer from solar radiation, especially the areas where the hair is thinning. Symptoms of extreme piebaldism include neurological defects or deafness in one or both ears.
Vitiligo is a genetic disorder, though it only becomes noticeable when an animal enters young adulthood. It is characterised by whitish patches of skin on the bridge of the muzzle and around the eyes, and sometimes also affects the claws and hair coat. Loss of color is dependent on how severe the disease is. Belgian Tervurens and Rottweilers are most susceptible to Vitiligo, with the gene running in some dog families. Although some animals undergo total remission, this is very rare. There are no other health problems associated with Vitiligo. There is no treatment for Vitiligo, and human treatments are not likely to work on animals.
Acquiredaurotrichia is a syndrome where the hair along the spinal cord changes color from the usual gray or black, to golden. It is typically observed in some lines of Miniature Schnauzers, though other breeds of dogs can also be affected. It is characterized by loss of hair, and becomes noticeable during young adulthood. Most of the time, there are no other skin changes or external symptoms. Majority of affected dogs regain their normal coat colour in 1 to 2 years.
Structural Integrity Defects
There are particular types of genetic skin diseases that affect the skin’s integrity or continuity.
Cutaneous asthenia (also known as Ehlers Danlos syndrome or dermatosparaxis) is characterised by the skin’s inability to produce sufficient collagen. Symptoms include stretchy, loose, weak skin, and problems with the joints. The condition is clear as soon as the animal is born, with the fragile skin, slow healing wounds, and loose-hanging skin being enough evidence for a diagnosis. Development of cysts and bruises may also occur, with older animals showing severe scars and having hanging folds of skin. Joint and eye problems are also displayed by some animals. The visible signs and testing of the collagen structure are ways of diagnosing it. A skin extensibility indicator has been created for cats and dogs, in order to assist your veterinarian analyse this syndrome. Though there are reported cases of affected dogs getting better after being given vitamin C supplements, it is important to consult your veterinarian to establish whether such supplements could be beneficial to your pet. This disease may be fatal.
Epidermolysis bullosa syndromes refer to a collection of congenital abnormalities that affect the linkages between the external and internal skin layers, causing skin blisters. The different varieties of epidermolysis bullosa have been witnessed in German Shorthaired Pointers, Shetland Sheepdogs, Akitas, Collies, Toy Poodles, Golden Retrievers, and mixed breed dogs. Even slight trauma to the skin causes separation of the layers of the skin, resulting in blisters that rupture to leave shiny, flat ulcers. Blisters tend to be a serious complication with puppies, as they appear at birth or within the first weeks of life. The feet, genitals, face, and mouth usually develop the most severe blisters. Majority of cases result in fatalities.
One disease that is hereditary in nature, especially in some line of Chinese Shar-Peisis cutaneous mucinosis. The Shar-Peis breed tend to have larger quantities of a protein called mucin than other dogs. Certain young dogs have so much mucin that the skin folds excessively and has pronounced blisters. The mode of diagnosis is via a skin biopsy or skin prick of the blisters. With maturity comes a reduction in the severity of the syndrome. It should be noted that an allergic skin disease, typical to this breed, can exaggerate this condition.
Multisystem Disorders Affecting the Skin
Young Collies and Shetland Sheepdogs tend to develop a hereditary inflammatory muscle and skin disorder called dermatomyositis. During the initial stages of the disorder, there are problems associated with skin and muscular blood vessels, causing wasting (atrophy). This usually occurs when the animal is less than 6 months old. There is also the possibility that different pups within the same litter are affected differently by the disease. The legs, face, tail tip, and ear tips all develop ulcers, hair loss and crusting; the condition is worsened by wounds, heat, and sun exposure. The head and leg muscles tend to be most affected. There are numerous ways to diagnose the condition, such as skin biopsy, muscle biopsy (must be conducted during the initial stages), electromyography, and evaluation of littermates and family history. It is rare for severely affected dogs to respond well to treatment, though vitamin E, omega-3 fatty acids and steroids may be useful.
Vasculopathy is a hereditary condition where skin ulcers appear soon after the initial group off puppy vaccinations, with the ulcers getting worse with every subsequent vaccination. It has been reported in Jack Russell Terriers and German Shepherds. Major symptoms include inflammation of all four footpads, crusting and ulcers on ear and tail tips, and discolouration of the bridge of the muzzle. Young Chinese Shar-Peis have recently been reported to have a severe type of hereditary neutrophilic vasculitis. With maturity comes the possibility of the disease going away on its own, though the severity of the ulcers on the footpads may necessitate euthanasia. Some dogs tend to respond positively to elevated doses of steroids, although there is no known effective treatment.
Lupoid dermatosis is a genetic condition affecting German Shorthaired Pointers, and is initially noted at 6 months of age. The initial symptoms include crusting and scaling on the head and upper body parts and legs. A rapid progression leads to a comprehensive scaling of the skin followed by redness (erythema), due to capillaries in the skin being congested. This causes a painful itchy for the affected animal, together with inflamed lymph nodes and fever. Skin biopsy samples analysed in a laboratory demonstrate signs of a lupus-like skin condition. The condition is progressive and eventually fatal. There is no effective treatment.
Some dog breeds are vulnerable to inherited zinc deficiency syndromes. White Bull Terriers suffering from lethal acrodermatitis show signs like boils around the mucous membrane, stunted growth, and thickened skin on the legs. Such symptoms are witnessed by the time the animal is 10 weeks old, followed later by pneumonia, diarrhoea, and fatality before the affected animal is 2 years old. Treating secondary infections is one way of prolonging of lives of affected dogs. Oral doses of zinc supplements don’t elicit any response from affected dogs, though German Shorthaired Pointers, Huskies and Alaskan Malamutes tend to respond well to zinc supplements. In most cases, there is development of oestrus and lactation signs in females. Skin biopsies are the common mode of diagnosis.