Medicated Shampoos: Washing Away Childhood Complaints

Dandruff, lice, and ringworm can bring parents to the pharmacy counter looking for solutions.

English speakers originally adopted “shampoo” from the Hindi word meaning “massage” in the 1700s, but they didn’t use it as a verb meaning “wash the hair” until the 1860s. Today, shampoos are big business,^1,2 and by the time children are in middle school and start to develop an interest in grooming and beauty, shampoo types, scents, and marketing promises are lunchtime debate.

Shampoo’s function is scalp cleansing. Used appropriately, it removes sebum, sweat, dirt, and styling products. Shampoo also prevents folliculitis and seborrheic dermatitis (eg, dandruff), because a brisk massage removes detritus and the shampoo’s foam sweeps it down the drain. Shampoos replaced bar soap, which leaves a difficult-to-rinse soap scum. Some shampoo ingredients (eg, detergents and forming agents) cleanse the hair, whereas others make it look, feel, or smell nice. The detergents used in shampoos are amphiphilic, attracting both oils and water.

Cosmetic chemists create different detergent types for varying hair types, and the American consumer has high expectations from shampoos. In fact, many shampoos now contain pharmaceutically active compounds (eg, ketoconazole), thus becoming “cosmeceuticals.”^1-3

Medicated Shampoo

Most often, medicated shampoos are used to relieve itching and/or scaling, but they can also treat bacterial or fungal infections and kill vermin. Patients ask for advice for products to treat dandruff and itching (The Table^2,4 describes common OTC products and their purposes). Just as the cosmetics industry is more likely than ever before to add pharmaceutically active compounds to their products, the pharmaceutical industry is more likely to formulate shampoos that are cosmetically elegant.²

Many youths struggle with greasy hair (seborrhea capitis) at and around puberty when increased sex hormone activity exacerbates sebaceous gland activity. When the sebum coating hair shafts captures environmental dirt, perspiration, and bacteria, it can develop an unpleasant odor due to microbial peroxidative lipid transformation. There are no prescription agents to reduce sebum production; those afflicted can only frequently wash with products designed for oily hair.^2,5,6

Scaly scalp affects about half of children and adolescents, and dandruff and seborrheic dermatitis are the primary causes. Researchers still don’t know the exact cause of dandruff—itching accompanied by flaking that often dusts theshoulders—but they do know the fungus Malassezia globosa is involved and feeds on sebum.^5,6 Mild cases respond to frequent shampooing with OTC selsun and zinc pyrithione shampoo, followed by copious rinsing.

Some dermatologists recommend rotating among 3 dandruff shampoos to prevent tachyphylaxis (decreasing benefit) when 1 shampoo is used. No studies support this belief.⁴ More stubborn cases of dandruff and seborrheic dermatitis may require ketoconazole 2% shampoo (available as an OTC), ciclopirox shampoo (for children 16 years or older), or the superpotent corticosteroid clobetasol proprionate 0.5% shampoo (for patients 18 years or older). Many of these products should only be applied 2 or 3 times a week. More frequent use will not increase efficacy.^3,7,8

Ringworm

Ringworm (tinea capitis) is also a common childhood problem. The most common dermatophyte infection occurs in children younger than 12 years. It presents in several different ways, with traditional ringworm appearing as patchy alopecia with scaling and raised borders. Some children have an intense immunologic response and will develop kerions (boggy, tender, inflammatory nodules). Others may develop follicular pustules, clusters with mild alopecia, or diffuse seborrheic-like scaling with little or no alopecia. Most tinea capitis is caused by Trichophyton tonsurans or Micdrosorum species that live in and around hair follicles.

Many parents will want a topical or a shampoo treatment for their children, perceiving it as easy to use. But topical treatments are only marginally effective, and most children will need systemic treatment, usually oral griseofulvin or an azole antimycotic (itraconazole or fluconazole) or terbinafine. Selinium sulfide shampoo is used as an adjunct to help remove dead skin cells and scales.^9-11

Lice

Several agents are available to treat head lice (pediculosis capitis), which is a major public health concern.¹² Lindane, the treatment mainstay for many years, has been associated with percutaneous absorption and systemic nervous system toxicity. It has been put aside in favor of other less toxic treatments such as pyrethrins or permethrin. Permetrin bonds to the hair longer than lindane and is technically a cream rinse.¹³ It can be used in children older than 2 months.

When lice infects a child, the entire household requires treatment. Treatmentresistant lice have been reported in some areas; experts attribute this to overuse and misuse of OTC products. Prescription agents used when OTC products are ineffective include benzyl alcohol lotion, lindane, and malathion-based products.^14-16

What to Know, What to Share

Pediatric patients—with or without their parents—may seek help from pharmacists. Sometimes, they’ll be looking for an OTC product to treat a simple and common problem. Many OTC products are available and suitable for dandruff, itching, or garden—variety lice. Pharmacists should refer patients if certain red flags are present:

• Broken skin or open wounds
• Itching or scaling of great magnitude or long duration despite OTC treatment
• Systemic involvement
• Presence of exudates or pus

As always, if pediatric patients ask for help and the problem seems serious, pharmacists should use good judgment and ask the child to involve the parent, explaining why parental involvement is needed.

Conclusion

An individual’s shampoo preferences vary by age, gender, ethnicity, and a plethora of other characteristics.^2,11,16,17 Humans value their hair as a part of their identity and style.³ When children and adolescents have problems with this natural ornament, it can be terribly upsetting. Often, a well-chosen shampoo can help restore the hair’s natural appearance—and the child’s happiness.

Ms. Wick is a visiting professor at the University of Connecticut School of Pharmacy and a freelance writer from Virginia.

References

• Bhushan B. Biophysics of Human Hair: Structural, Nanomechanical and Nanotribological Studies. London: Springer Heidelberg Dordrecht; 2010.
• Draelos ZD. Essentials of hair care often neglected: hair cleansing. Int J Trichology. 2010;2:24-29.
• Trüeb RM; Swiss Trichology Study Group. The value of hair cosmetics and pharmaceuticals. Dermatology. 2001;202:275-282.
• Schwartz JR, Rocchetta H, Asawanonda P, Luo F, Thomas JH. Does tachyphylaxis occur in long-term management of scalp seborrheic dermatitis with pyrithione zinc-based treatments? Int J Dermatol. 2009;48:79-85.
• Ro BI, Dawson TL. The role of sebaceous gland activity and scalp microfloral metabolism in the etiology of seborrheic dermatitis and dandruff. J Investig Dermatol Symp Proc. 2005;10:194-197.
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• Parasites-lice-head lice. Centers for Disease Control and Prevention website. www.cdc.gov/parasites/lice/head/index.html. Accessed January 4, 2012.
• Bowerman JG, Gomez MP, Austin RD, Wold DE. Comparative study of permethrin 1% creme rinse and lindane shampoo for the treatment of head lice. Pediatr Infect Dis J. 1987;6:252-255.
• Burkhart CG, Burkhart CN. Safety and efficacy of pediculicides for head lice. Expert Opin Drug Saf. 2006;5:169-179.
• Burkhart CG. Relationship of treatment-resistant head lice to the safety and efficacy of pediculicides. Mayo Clin Proc. 2004;79:661-666.
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• Shapiro J, Maddin S. Medicated shampoos. Clin Dermatol. 1996;14:123-128.
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