Seborrheic dermatitis affects a much smaller percent of the population and is characterized by severe flaking, inflammation, redness and itchiness. It is a very easily treatable condition. Seborrhea commonly manifests itself as a red, scaly, itchy rash most commonly seen on the scalp, sides of the nose, eyebrows, eyelids, skin behind the ears, and middle of the chest. Seborrheic dermatitis can also effect the navel (belly button), buttocks, skin folds under the arms, axillary regions, breasts, and groin, or other places where there are flaps of skin.

Causes of seborrheic dermatitis: Seborrheic dermatitis can occur within patients that have neurological disorders such as Parkinson's disease. Patients recovering from traumatic events such as heart attacks can develop seborrheic dermatitis. People in hospitals or nursing homes and people with immune system disorders can more prone to the disease. Most research will support the theory that a microorganism called "pityrosporum ovale", which is normally present in the skin, but can begin to feed on the dead skin cells and cause a rapid shedding of the skin, which appears as large, oily flakes and causes a red, itchy scalp. Normally, the skin will shed every 28 days, but this microorganism can cause the skin to shed every 7-21 days, like dandruff. Seborrheic dermatitis can also be called "Cradle Crap" and can occur in small infants.

Seborrheic Dermatitis treatment: Seborrheic dermatitis can be easily treated with a solution which contains  coal tar. Coal tar formulations are as effective as prescription products, yet costs about one-third as much. You should start seeing results from a tar formula within a few days of treatment. You should notice the scales begin to disappear and the scalp should become soft. Unlike with psoriasis, you don't have to worry about building up a tolerance to shampoo treatments that include salicylic acid and ketoconazole.

Dandruff affects approximately 50% of the population in some mild to severe form. Dandruff Seborrheic dermatitis, a more severe form of dandruff is a chronic skin condition that affects the scalp. Dandruff manifests itself as dry skin, flakiness, itchiness and oily skin. Shedding of the skin is natural. Most people shed a layer of skin per month. People who suffer from dandruff shed their skin much faster and the result is a noticeable amount of flakiness.

In the normal healthy process of the scalp, new skin cells are continually being generated and are formed at the lowest level of the skin. These cells when formed, move to the outer surface about every 28 days, where they become flat and they shed unnoticed. With dandruff and seborrheic dermatitis, this process accelerates (most likely due to the fungus) and the skin rotates or sheds much faster and more like every 7-21 days. The result of the faster shedding is rather than flat, unseen cells, large clumps agglomerate from hundreds or thousands of microscopic cells and what you see are the flakes.

Dandruff Causes: Dandruff and seborrheic dermatitis are caused by a naturally occurring fungus that we all have called Malassezia that feeds on the skin's natural oils. Malassezie can cause irritation and speed up the shedding of skin. What determines the amount of dandruff or seborrheic dermatitis is a person's tolerance to the fungus.

What is the difference between dandruff and just dry skin? The main difference iare flakes from dandruff are medium to large in size. The flakes are usually white and oily in appearance. The flakes are believed to be caused by Malassezia, a naturally occurring fungus found on the scalp. Dry scalp on the other hand is not quite as noticeable and is characterized by smaller flakes, excessive itching and occurs when your scalp lacks its natural oils.

Psorias: Psoriasis is similar to seborrhea and eczema in its symptoms. According to the American Academy of Dermatologists, psoriasis is a "persistent skin disease that got its name from the Greek word for "itch." The skin becomes itchy, inflamed and produces silvery scales which are thickened and occur most often in the scalp, knees and lower back. The scales are also common in areas of the body where there are folds of skin. Psoriasis is not contagious. Approximately 2% of the population is affected with psoriasis. Approximately 150,000 new cases of psoriasis occur each year. Although the cause of psoriasis is unknown, the same result occurs as dandruff and seborrhea, which is the rapid shedding of skin. The skin becomes inflamed for some reason (perhaps due to a white blood cell abnormality), and the skin begins to become inflamed. Because of the inflammation, the shedding begins. In fact the shedding of skin is approximately every 3-4 days. Psoriasis can also be activated by cuts, abrasions, sun burn and scratches.

Psoriasis flare-ups often occur in the winter when the skin is dry and flaky and as a result of the lack of UV sunlight. Each flare-up differs in severity, duration, location, and in the shape and pattern of the scales. The most common form begins with little red bumps. Gradually these grow larger and scales form. While the top scales flake off easily and often, scales below the surface stick together. When they are removed, the tender, exposed skin bleeds. These small red areas then grow, sometimes becoming quite large. Elbows, knees, groin and genitals, arms, legs, palms and soles, scalp and face, body folds and nails are the areas most commonly affected by psoriasis. It will often appear in the same place on both sides of the body. Nails with psoriasis have tiny pits on them. Nails may loosen, thicken or crumble and are difficult to treat.