• Deep pink to red, raised patches of skin with a sharp border, and covered with silvery-white scales, which are shed from the skin.
• Some people also experience itchiness, but this does not always occur.
• The most common locations are the scalp, elbows, knees, wrists, buttocks and ankles. 
• Pitting of the fingernails and toenails may occur, giving the nails the appearance of a thimble.
• Some people develop an associated arthritis, which is characterised by joint pain, tenderness and swelling that may affect a single or multiple joints, especially those of the fingers, toes, lower back, knees, ankles and wrists.
  

In psoriasis the skin cells multiply at a rate approximately 1000 times faster than normal, healthy cells.

There is no corresponding increase in the rate at which cells are shed, causing a build-up which appears silvery and raised. The underlying issue may be related to an imbalance in two compounds that governs the rate at which cells multiply and are sloughed off, called cyclic adenosine monophosphate (cAMP) and cyclic guanidine monophosphate (cGMP).

Hereditary factors are known to be involved in psoriasis, and there is a strong tendency for the condition to run in families. It is not contagious.

Possible triggers for psoriasis attacks include stress, shock, infection, and excessive alcohol intake.

From a naturopathic perspective, other factors that may contribute include immune dysfunction, poor bowel function, sluggish liver function, and an inability to completely digest proteins.

An imbalance of essential fatty acids (for example, high consumption of saturated animal fats ) has also been implicated.

• High doses of omega-3 oils from fish may be beneficial in psoriasis as abnormalities of essential fatty acids may be a contributing factor to the condition. A suitable dose for adults is 1.8 g of EPA and 1.2 g of DHA per day.
• Low levels of vitamin A and zinc are common in patients with psoriasis, and it may be useful to take supplements. Cod liver oil is a rich natural source of vitamin A, and helps maintain and support healthy skin. 
• Improving liver and bowel function may help in the treatment and prevention of psoriasis. Milk thistle aids normal liver function and supports the regeneration of liver cells. It has traditionally been used to support detoxification.
• In Western herbal medicine, bitter tasting herbs such as gentian and dandelion root are traditionally regarded as tonic herbs for the digestive system. It is believed that when their bitter flavours are sensed by the tastebuds, a reflex action stimulates the production of saliva and digestive juices, enhancing the functioning of the stomach, liver, gall bladder and bowel and aiding symptoms of poor digestion, such as nausea, indigestion and poor appetite.