Among the most common conditions of the human scalp are flaking dead skin cells (dandruff), excessive oiliness (seborrhea), and oily crusts adhering to inflamed, itchy, moist scalp skin (seborrheic dermatitis). These conditions usually begin while a person still has a full head of hair, and they persist as hair begins to be lost due to androgenetic alopecia (male or female-pattern hair loss).
Dandruff
The condition popularly known as dandruff is, in its most common and mild form, little more than a normal shedding of dead skin cells from the scalp. When the white flakes land on the collar or shoulders of one’s clothing they become an unattractive cosmetic nuisance. Some people experience a heavier accumulation of flakes that adhere to the scalp and fall in a literal blizzard onto clothing, bedding and furniture. When a person has excessive oiliness of the scalp, a heavy accumulation of flakes can be pasted to the scalp in oily mounds and adhere to hair in whitish globs. This condition is most likely when production of skin oils (sebum) is at its peak in puberty and adolescence, or when the production of androgenetic (male) hormones is out of balance. “Oily dandruff” that is not accompanied by inflammation or itching may be a mild form of seborrheic dermatitis that is discussed below.
Common, mildly shedding dandruff is usually managed successfully by regular use of a mild, anti-dandruff shampoo once or twice a week. Over-the-counter shampoos containing ketoconazole, zinc pyrithione tar or selenium oxide often work well to manage mild dandruff. It is a condition of no medical consequence. More severe dandruff with excessive oiliness, crusting and itching may be a form of seborrheic dermatitis and should be managed under the care of a dermatologist or other physician.
The topical hair restoration medication minoxidil (Rogaineâ) can cause or worsen dandruff in some patients. Dandruff due to this cause varies from mild to severe. In some cases minoxidil can cause scalp irritation, dryness and itching that can progress to broken and bleeding scalp skin. The condition may be worse in winter when humidity is low. When a side effect of this severity occurs, the patient should contact his or her physician. Dandruff and dry, irritated skin associated with minoxidil can be treated with anti-dandruff shampoos, decrease of the drug dose from twice to once a day, or discontinuation of the medication.
Seborrhea—Oily Skin, Scalp and Hair
The sensation of “oiliness” or “greasiness” of skin, scalp and hair is one that most people dislike and believe to be unattractive to other people as well. To some extent, the perception of “oiliness” or “greasiness” is highly personal and may or may not be objectively identified with excess skin oil (sebum) production. A feeling of oiliness in hair may also be associated with accumulation or degradation of hair cosmetic products, or with accumulation of by-products of heavy scalp perspiration. Excess sebum production frequently occurs during adolescence—a peak period from which sebum production usually declines as a person ages.
Excess sebum production is a clinically important feature in many cases of acne, and treatment of acne may include treatment to reduce sebum production. While acne is commonly believed to be a teen-age disease it persists into adulthood for millions of people.
Seborrhea can cause scalp and hair to feel oily or greasy. Unlike seborrheic dermatitis, however, the oiliness is not associated with crusting, inflammation and intense itching. The cause of severe seborrhea should be diagnosed by a dermatologist in order to rule out other conditions and determine the best treatment.
Seborrheic Dermatitis
Seborrheic dermatitis is a common, chronic condition that affects people at all ages from infancy through middle age; however, the two peak periods of occurrence are in the first 3 months of life when seborrheic dermatitis is known as “cradle cap”, and from approximately ages 30 to 70 years.
The most prominent features of seborrheic dermatitis are (1) excessive oiliness of scalp and hair, (2) greasy, yellowish scales that grow into crusts covering red, inflamed, moist scalp skin, and (3) intense itching. In more severe cases the condition involves the eyebrows, cheeks, and folds of the nose. The intense itchiness may encourage hard scratching that will enhance inflammation and open the way to secondary infection by bacteria, yeasts or fungi. The more severe forms of seborrheic dermatitis can closely resemble psoriasis, and may even overlap in a condition called sebopsoriasis. The cause of seborrheic dermatitis is not known.
Of the three conditions—mild dandruff, seborrhea, and seborrheic dermatitis—seborrheic dermatitis is likely to be the most severe and should usually be diagnosed and treated by a dermatologist or other physician experienced in the treatment of skin disease. Treatment of seborrheic dermatitis usually includes daily to twice-weekly shampoos with a product recommended by the patient’s physician. Additional forms of treatment depend upon the severity of disease. as diagnosed by a physician. Although not curable, seborrheic dermatitis is very treatable and can usually be cleared with regular use of prescribed treatments.