Psoriasis is a common skin condition in humans, affecting 2-3% of the population of the United Kingdom. It can also affect dogs and is caused by a weak immune system. When their T-cells (a type of immune cell) divide more rapidly than usual with less time to shed, they accumulate on the surface of their skin to form a scaly rash. Symptoms include dry, red or bright pink, scaly plaques that tend to form at the tips of their elbows, scalp, legs and sacral area (on the spine between the hips). As the redness fades, silvery scales can develop. Allergies to commercial dog food can also cause excessive dandruff and scaling, which can be an early sign of psoriasis. Psoriasis has many potential causes, such as such as an allergic reaction to shampoo, flea medication, plants, and fabric. You need to discover the specific cause of your dog's condition in order to determine the best treatment plan. The best way of doing this is to eliminate any substances or products which have recently been introduced to the dog's environment. If the symptoms persist, take your pet to the vet as soon as possible. They will be able to run tests to determine the cause and best form of treatment in each individual case. Sometimes psoriasis is caused by the dog's genetics. Common treatments and pain relief include pet moisturisers, which will alleviate dryness and itching to prevent your dog from itching the affected areas. Primrose oil and products containing coal tar and sulphur are also used. Boosting your dog's immune system by introducing nutritional supplements are a way of preventing the return of psoriasis as well as an improved diet. Dog food that contains whole grains, fibre and is low in carbohydrates is good for dogs with skin problems.