US Pharm. 2013;38(6):26-31.
Patients approach pharmacists with a host of questions about relatively minor health conditions, and many involve the skin. Dermatologic questions concern allergic dermatitis, dry skin, minor wounds, and numerous other problems.1 Dandruff and seborrheic dermatitis (SD) are two closely related dermatologic conditions that may be successfully self-treated. However, the pharmacist should be aware of the various means by which both are recognized and the possible interventions.
Dandruff is a common condition that affects up to 50% of the population.2-4 Age and sex influence the occurrence of dandruff. Most patients begin to notice dandruff during puberty.5 Dandruff may continue through middle age and then abate, but some patients will deal with it for their entire lives.
Excess skin oil (sebum) is an underlying contributor to dandruff epidemiology, as illustrated by its preference for males, postpubertal age, and poor hygiene. It is more common in male patients due partly to the influence of androgens but also to the fact that males have larger sebaceous glands on the scalp, especially after puberty.5 Their larger glands produce more oil than those of an age-matched set of females. Further, during the onset of puberty, the skin’s sebaceous glands mature into multilobulated configurations, allowing them to produce a heightened amount of sebum, which also leads to acne. Finally, patients who do not bathe or shampoo daily experience an accumulation of oil on the skin and scalp.5
An improper diet may contrib-ute to dandruff, especially if it is low in zinc, B vitamins, or specific types of fats. Dandruff also appears to be more common in patients with compromised immune status or Parkinson’s disease and in those recovering from stress-related situations such as a recent heart attack or stroke.5
Etiology: A lipophilic skin fungus known as Malassezia furfur is able to feed on the excess sebum present in the situations previously described, and is hypothesized to be a major cause of, or contributor to, dandruff.4 Although most adult scalps are colonized with Malassezia, many patients do not complain of dandruff. The exact reason why some people develop dandruff and others do not remains to be fully elucidated.4 While the fungal hypothesis for dandruff has gained widespread acceptance, there is no evidence that dandruff spreads from one individual to another.3
Manifestations: The hallmark sign of dandruff is excess flaking of the scalp. Normal stratum corneum constantly sheds its upper layer, but the shed skin cells are normally not noticed. Why is dandruff different? Dandruff cells have developed an abnormal cohesion, so much so that the resulting scales are visible and unsightly.2 They are usually white with an oily consistency due to the sebum.5 Many patients experience scalp itching, perhaps due to irritation from fungal growth residues.3,6 Occasionally, the scalp may appear erythematous.7
Treatment of Dandruff: Patients may choose from a wide array of therapeutic shampoos for dandruff.1 These products contain zinc pyrithione, selenium sulfide, salicylic acid, coal tar, or keto-conazole. Zinc pyrithione 1% shampoos include Head & Shoulders, Pert, and Zincon. Labels direct consumers to apply, rinse, and repeat if desired every time the hair is shampooed, but at least twice weekly or as directed by a physician. Selenium sulfide 1% shampoos include Selsun Blue, which directs the consumer to shake the bottle before pouring and to use it at least twice weekly or as directed by a physician. Selenium sulfide occasionally causes orange to red-brown scalp discoloration. The apparently harmless pigmentation disappears shortly after the product is discontinued, a process that can be aided by lightly swabbing the discolored areas with isopropyl alcohol.8
Salicylic acid 3% shampoos include T/Sal, which directs users to lather it onto the scalp, leave the lather in place for several minutes, and rinse, at least twice weekly or as directed by a physician.1
Coal tar shampoos are labeled for dandruff, but should only be a last resort due to the relatively serious warnings on their use.1 One such product is Denorex Therapeutic, containing 2.5% coal tar. The label directs consumers to shake the bottle well and shampoo at least twice weekly or as directed by a physician. The label also cautions users to keep it away from fire and flame due to extreme flammability (it contains 10.4% alcohol). Consumers are warned not to use coal tar shampoos for prolonged periods without asking a doctor and to consult a physician before use if the condition covers a large part of the body.1 This latter warning is necessary because coal tar products are also proven safe and effective to treat conditions not limited to the scalp, such as SD and psoriasis.
Those using coal tar products should be cautious in exposing treated areas to sunlight, as coal tar can increase the tendency to burn for 24 hours after application. A special label states that the product contains a chemical known to the State of California to cause cancer (referring to coal tar).1
Topical ketoconazole shampoo (Nizoral A-D) is another viable option for dandruff.1 As of this writing it is difficult to locate, but apparently has not been formally discontinued. It is to be used every 3 to 4 days for up to 8 weeks, and as needed thereafter. Patients are cautioned to stop use if dandruff worsens, if a rash appears, or if dandruff does not improve in 2 to 4 weeks. The product should not be used in persons under the age of 12 years or in those who are pregnant or nursing. Patients should not use it if the scalp has broken skin or inflamed areas.
SD is a chronic condition marked by remissions and exacerbations. At the present time, no cure is known. SD affects approximately 3% to 5% of U.S. citizens, but the incidence is as high as 85% in AIDS patients.9,10 Males are more likely to experience SD. It is more common after puberty, although infants may experience a variant of SD known as cradle cap (discussed later).9 SD generally becomes less common as people age, although many experience exacerbations throughout life.9 Patients with certain central nervous system disorders may experience increased accumulation of sebum, predisposing them to SD. This includes conditions limiting patient mobility, such as stroke, Parkinson’s disease, head injury, cranial nerve palsies, and major truncal paralyses.9,11
There is an inherited tendency to experience SD, so those with a close relative with SD are at greater risk.11 Further, individuals with oily skin, acne, or obesity appear to be predisposed to SD.12 Those who are stressed or fatigued are at higher risk. Persons who do not bathe or shampoo frequently experience higher rates of SD. Patients who engage in outdoor activities during the summer may find that the condition improves.11
Etiology: The etiology of SD is similar to that of dandruff. M furfur is presumed causal in most patients, especially when a therapeutic trial of topical antifungal medications (e.g., ketoconazole cream) clears the condition and prevents its recurrence, as is often the case.9,13-15
Manifestations: SD produces skin scales that are yellowish in color, oily in consistency, and tend to adhere to the skin.11 The affected areas of skin are erythematous and pruritic. Plaques may cover large areas of the body, although they are more often found where sebaceous glands are most heavily concentrated. Many patients have lesions on the head, such as the scalp and its margins; on the eyebrows, eyelids, lips, side creases of the nose, nasolabial fold, and forehead; in the inner ear canal; behind the ears; and in the mustache/beard area. Other common attack sites are on the trunk (e.g., the midchest, anogenital region, beneath the breasts) and in all body folds, such as the groin, axillae, and navel.11,16 The distribution is symmetrical, making it unusual to have only one side of the body affected and the opposite side completely normal.
Treatment of SD: Patients with SD on the scalp are urged to wash daily with FDA-approved shampoos. They should first loosen SD scales with their fingers, scrub vigorously with the shampoo for at least 5 minutes, and rinse thoroughly, unless the product’s label provides different directions. Ingredients proven safe and effective for self-treatment of SD include the coal tar, zinc pyrithione, selenium sulfide, and salicylic acid products mentioned earlier. Nizoral A-D does not carry labeling for treatment of SD. However, hydrocortisone, ineffective for dandruff, is effective for SD. Patients with SD on the face or trunk might be advised to engage in a trial of hydrocortisone (e.g., Cortaid), applied twice daily. The pharmacist can also suggest that patients visit a physician to obtain a prescription for topical ketoconazole.13
Cradle Cap: Cradle cap is a relatively innocuous condition in which a baby’s scalp is covered with thick, crusted, yellow to brown scales.11 It usually disappears by 1 to 3 years of age.5,11 It may be pruritic, causing the baby to scratch the area. Scratching leads to inflammation or infection in some cases. Cradle cap is defined by some authorities as a type of dandruff.5 Others definitely state that it is related to SD.11
Pharmacists can advise parents of several helpful steps when their infant has cradle cap.11 The parent should massage the scalp gently with the fingers or a soft brush to promote healthy circulation and remove scales. When scales are present, the scalp should be washed daily with a gentle, mild shampoo, making sure to thoroughly rinse all soap from the scalp. If the condition resolves, parents may back off to twice weekly shampooing. They should brush the child’s hair with a clean, soft brush after shampooing and several times each day. To remove scales that seem to be more strongly attached, parents should place mineral oil on the scalp and wrap it with a wet, warm cloth, leaving this in place for an hour before the shampoo. Parents should check the cloth to make sure it remains warm in order to prevent chilling the baby. If these steps do not help, parents should take the child to the pediatrician to ensure that there is nothing more serious occurring.
What Is Dandruff?
Dandruff occurs only on the scalp. It is so common that almost everyone has seen it, as the embarrassing flaking of scalp skin that many people find cosmetically unacceptable. The flakes have a characteristic look, are somewhat oily, and seem to be present on a good part of the scalp. Someone with dandruff may also notice itching in the areas with the worst flaking.
Dandruff usually begins in the teen years when you go through puberty. It may improve as you age, although some people struggle with it all their lives. It is more common in men because their oil-producing glands are larger than those of women. It is worse in winter because the air is drier. Dry air causes the skin to dry out, and dry scalp skin is more prone to develop dandruff.
What Is Seborrheic Dermatitis?
Seborrheic dermatitis may occur on the scalp but also on such oily skin areas as inside or behind the ears, on the creases at the sides of the nose, or on the eyelids, eyebrows, lips, face, upper chest, or back. It also causes scales that are white or yellow. The affected skin may also be reddened, and it may itch.
If one family member has seborrheic dermatitis, others are more likely to develop it. The condition seems to worsen under certain circumstances, such as stress, fatigue, extreme weather conditions, excess skin oiliness, failure to bathe or shampoo daily, use of alcohol-containing lotions, or presence of acne or obesity.
Treatment of Dandruff and Seborrheic Dermatitis
You can try several products to see if they help dandruff or seborrheic dermatitis. Since both affect the scalp, there are several shampoos you may find beneficial.
For dandruff, there are many product options. Zinc pyrithione as found in Head & Shoulders, Pert, and Zincon shampoos is a good ingredient to try. Follow all label directions for use. Selenium sulfide as found in Selsun Blue is an alternative that is helpful. Salicylic acid helps dandruff and is found in Ionil Plus, Scalpicin Scalp Liquid, T/Sal, and Denorex Extra Strength.
A product called Nizoral A-D shampoo contains ketoconazole, a medication that attacks the fungus that can contribute to dandruff in some patients. It is worth a trial to see if the fungus can be controlled in your case.
Seborrheic dermatitis responds to all of the medications listed above except Nizoral A-D. Any may be beneficial. You may also try a trial of nonprescription hydrocortisone for seborrheic dermatitis, using a product such as Cortaid.
If your condition fails to respond to these interventions, you may need to visit a physician for a prescription medication such as ketoconazole cream. Applied once daily, it may effectively prevent the seborrheic dermatitis symptoms. Your physician can also check to see whether the condition is a more severe problem.
Remember, if you have questions, Consult Your Pharmacist.
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