It is also known as seborrhea. It isdefined as the excessive shedding of dead skin cells. It occurs in parts of thebody with high oil (sebum) production..  Body areas that are commonly affectedinclude the scalp (most common site), ears, face, chest, and folds of skin,such as the underarms etc.

A small amount of flaking is normal and in fact quite common.Some people, however, experience an unusually large amount of flaking due torapid turnover of cells. For people with dandruff, skin cells may mature and beshed in 2-7 days, as opposed to around a month in people without dandruff. Theresult is that dead skin cells are shed in large, oily clumps, which appear aswhite or grayish patches.
1.Most common cause for it is fungus named Malassezia furfur.This fungus metabolizes triglycerides present in sebum by the expression oflipase, resulting in a lipid byproduct oleic acid (OA). Penetration by oleicacid of the top layer of the epidermis, the stratum corneum, results in aninflammatory response in susceptible persons, which disturbs homeostasis andresults in erratic cleavage of stratum corneum cells.
2.Some people who have weakened immune systems, such as thoseon chemotherapy or those with HIV disease or certain neurological disorders,may have very severe seborrhea.

Scalp Seborrhea Manifestation:
1.Hair loss but not permanent.
2.Itching is present, when proper hygiene is not maintained.
3.Thick, dry patchy flakes present.
4.Affected part is seems to be dry but appeared reddish afterapplication of moisturizer.

Seborrheic Dermatitis Manifestation:
1.It is frequently occurs around the folds of the nose and theeyebrow areas.
2.Reddish-brown, dry-looking, or thick, greasy scales on theeyebrows, sides of the nose, and behind the ears.
3.Redness and itching is often associated.

Differential Diagnosis:
Scalp psoriasis and seborrheic dermatitis of the scalp can bedifficult to differentiate. Both are common conditions that affect the scalp.In addition, they share similar symptoms, such as itchy, red, scaly skin.
Most often, the scales of psoriasis are thicker and somewhatdrier in appearance than are the scales of seborrheic dermatitis. In addition,psoriasis usually affects more than one area of the body. So if you have scalppsoriasis, you may also have mild psoriasis on your elbows, knees, buttocks orfingers.
There is no single test to confirm a diagnosis of psoriasis orseborrheic dermatitis. A diagnosis is usually made with a visual examination ofthe affected skin.

The most effective way to control dandruff is to keep the affected area clean; a proper hygiene must be maintained. All shampoos andother product which are given to control dandruff will give just a temporaryrelief but with the help of homoeopathic medicines the tendency and symptomsboth can be treated without any further adverse effects.

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