Medicated Shampoos are Effective in Many Scalp Conditions

ABSTRACT
Scalp conditions such as itchy scalp, dandruff, seborrheic dermatitis, and scalp psoriasis are common. The emotional effect these complaints cause are often ignored or trivialized, but as dermatologists we should appreciate the relief that appropriate advice and treatment will bring to our patients. These scalp ailments respond to the regular or periodic use of readily available OTC medicated shampoos. Effective medicated shampoos are also available for the treatment of scalp infestations such as ringworm and head lice, replacing the unpleasant-to-use lotions frequently utilized in the past.

Key Words:
itchy scalp, dandruff, seborrheic dermatitis, scalp psoriasis, Pediculosis

Although more than $1 billion dollars are spent annually on medicated shampoos and dermatologists frequently recommend their use, until recently scientific evidence supporting their use was marginal. This mini-review summarizes current information on a group of skin care products, much used by the public but often given insufficient attention by we practitioners.
Dr Stuart Maddin, Editor

Dandruff and Seborrheic Dermatitis

Dandruff and seborrheic dermatitis are generally caused by the Pityrosporum ovale yeast. They are treated with shampoos containing anti-fungal agents, such as ketoconazole, zinc pyrithione, selenium and sulphur.¹

• Ketoconazole – Ketoconazole has become our treatment of choice. A number of studies have shown that ketoconazole 2% shampoo (Nizoral®) is safe and effective in the treatment of seborrheic dermatitis. One multicentre, placebo-controlled clinical trial in 575 patients demonstrated that twice weekly application of this shampoo for 2-4 weeks was highly effective in clearing scalp seborrheic dermatitis and dandruff. Furthermore, weekly prophylaxis prevented a relapse of disease in the vast majority of patients.² In animal models, ketoconazole 2% shampoo has been shown to be more effective than zinc pyrithione and selenium sulphide.³ In addition, although ketoconazole 2% shampoo and selenium sulphide 2.5% shampoo were found to be equally effective in a comparative clinical trial in 246 patients, ketoconazole shampoo was better tolerated.⁴ Ketoconazole 2% shampoo was initially prescription only but is now available OTC in most countries except the USA.
• Zinc pyrithione (e.g. Head and Shoulders®, zinc pyrithione 1%) shampoo, available OTC, has proven its effectiveness since becoming available in the 1960s. The mechanism of action is more likely to be antimicrobial rather than cytostatic as was once thought.1SkinCap®, is an interesting zinc pyrithione containing formulation with a labelled indication for the treatment of seborrheic dermatitis. This aerosol spray developed by Cheminova International of Madrid, Spain, has recently become available in the US and Canada. Its off-label use for psoriasis has generated considerable interest and controversy. A double-blind, vehicle controlled clinical trial evaluating its use in psoriasis is underway at the University of Minnesota.
• Selenium shampoos (e.g. Selsun Blue®, selenium sulfide 1%) have been available since the 1950s. Their mechanism of action is unclear but may be antimicrobial.¹

Scalp Psoriasis

In a previous Skin Therapy Letter (Volume 2, Number 2), we described specific topical gels and lotions for stubborn scalp psoriasis. For these cases, thick and adherent scaling must be removed by a keratolytic prior to further treatment, potent prescription only products are frequently required and it is often necessary to rotate various treatments. For less severe cases of scalp psoriasis, coal tar shampoos are popular. However, as discussed in Skin Therapy Letter (Volume 1, Number 1), the safety of coal tar preparations is being re-evaluated because of their teratogenic and carcinogenic potential. Alternatives to coal tar shampoos, such as salicylic acid, sulphur or selenium shampoos have not been shown to be particularly effective.¹

Tinea Capitis

Tinea capitis, or scalp ringworm caused primarily by Trichophyton tonsurans or Microsporum canis, is still a major childhood problem. The condition can be treated with oral griseofulvin (with or without selenium sulphide shampoo), oral ketoconazole or ketoconazole 2% shampoo.⁵

• Ketoconazole – Tinea capitis is a relatively new indication for ketoconazole shampoo. Dr. Greer has found that in children less than one year of age, shampooing once daily often clears the scalp within two weeks and produces a mycological cure within two to four weeks. In older children, clearance may require four to eight weeks.⁶ More recent work from Greer suggests that in both home and institutional settings, ketoconazole shampoo 1% may be sufficiently effective for the prophylactic management of T. capitis.⁷ Ketoconazole shampoo 2% is not available OTC in the USA.
• Selenium Sulphide – A randomized, placebocontrolled trial in 55 children with Trichophyton tonsurans tinea capitis showed that 2.5% selenium sulphide prescription lotion and the less expensive OTC 1% selenium sulphide shampoo were equally effective when given in combination with 15mg/kg/day of griseofulvin. Griseofulvin/selenium sulphide combination therapy was superior to griseofulvin alone.⁸

Pediculosis

Head lice infestations (pediculosis) are a major public health concern worldwide. The product of choice for this condition is permethrin shampoo (“creme rinse”). Shampoos containing lindane, malathion and pyrethrin can also be used but tend to be associated with side effects.¹

• Permethrin – Permethrin 1% creme rinse (Nix®) is available OTC. In a comparative, placebo-controlled, clinical trial in 1040 patients, permethrin 1% creme rinse was significantly (p < 0.001) more effective than lindane. Two weeks after treatment, 98% of permethrin 1% creme rinse recipients were louse-free , compared with 76% of those who received lindane shampoo. Erythema, pruritus or other mild dermal reactions occurred in 1.2% of permethrin-treated and 2.6% of lindane-treated patients.⁹ This superiority of a single application of permethrin 1% creme rinse over lindane shampoo is also supported by data from additional randomized, controlled studies.^10,11

Whether a patient has a common dermatological condition such as dandruff; a troublesome chronic condition such as psoriasis; or a parasitic infestation or fungal infection of the scalp; effective, relatively safe, and easy to use medicated shampoos are now available for treatment.

References

1. Shapiro J, Maddin S. Medicated shampoos. Clinics in Dermatology 1996; 14: 123-128.
2. Peter RU, Richarz-Barthauer U. Successful treatment and prophylaxis of scalp seborrhoeic dermatitis and dandruff with 2% ketoconazole shampoo: results of a multicentre, double-blind, placebo-controlled trial. Br J Dermatol 1995; 132: 441-445.
3. Van Cutsem J, Van Gerven F, Fransen J, et al. The in vitro antifungal activity of ketoconazole, zinc pyrithione, and selenium sulfide against Pityrosporum and their efficacy as a shampoo in the treatment of experimental pityrosporosis in guinea pigs. J Am Acad Dermatol 1990; 22: 993-998.
4. Danby FW, Maddin WS, Margesson LJ, Rosenthal D. A randomized, doubleblind placebo-controlled trial of ketoconazole 2% shampoo versus selenium sulfide 2.5% shampoo in the treatment of moderate to severe dandruff.. J Am Acad Dermatol 1993; 29: 1008-1012.
5. Maddin S. Current dermatologic therapy II. Second edition. Philadelphia: WB Saunders, 1991.
6. Greer DL. Successful treatment of Tinea capitis with 2% ketoconazole shampoo. [Poster] AAD San Francisco, March, 1997.
7. Greer DL. Personal communication. July, 1997.
8. Givens TG, Murray MM, Baker RC. Comparison of 1% and 2.5% selenium sulfide in the treatment of tinea capitis. Arch Pediatr Adolesc Med 1995; 149: 808-811.
9. 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.
10. Brandenburg K, Deinard AS, DiNapoli J, et al. 1% permethrin cream rinse vs 1% lindane shampoo in treating pediculosis capitis. Am J Dis Child 1986; 140: 894-896.
11. Taplin D, Meinking TL, Castillero PM, Sanchez R. Permethrin 1% creme rinse for the treatment of Pediculus humanus var capitis infestation. Pediatr Dermatol 1986; 3: 344-348.