Pityriasis Capitis

Pityriasis capitis By Daphne Gima 2nd September 2009

Outline  Introduction  Clinical

Features  Etiology  Treatment  Evidence for Use  Prevention  Summary  References

Introduction  Chronic

relapsing non-inflammatory hyperproliferative skin condition.  Affects both sexes  Affects all age groups; though unusual in prepubescent children.  Otherwise known as dandruff

Clinical Features    

White or gray scaling or flaking Mild pruritus (possible) No inflammation No alopecia Differential Diagnoses: i) Inflammatory changes such as erythema & pruritus are present  seborrheic dermatitis ii) Alopecia present  psoriasis

Etiology   -

Abnormal cell turnover: Normal cell turnover: 25 -30 days In dandruff: 13 -15 days In seborrhoeic dermatitis: 9 -10 days Fungal etiology: Malassezia spp (previously known as Pityrosporum sp ) Lipophilic yeast, inhabits follicles Cannot synthesize fatty acids ≥ C12 Metabolize fatty acid from surrounding → irritation

Treatment Strategies 3

main classes according to mechanisms: - Keratolytic - Antimicrobial - Antiproliferative  All antidandruff shampoos can cause local scalp irritation.  Generally safe in pregnancy,  No drug interactions.

Selenium Sulfide 1%  Proven

cytostatic agent, highly inhibits growth of P. ovale  Studies shown significantly better than placebo and non-medicated shampoos  Only used in patients > 5 years.  E.g. Selsun

Zinc Pyrithione  Exhibit

antifungal properties and reduce cell turnover rate  Can be used by all patients at any age  Use on daily basis until dandruff clears  E.g. Head and Shoulders

Ketoconazole 1%  Antifungal

activity controls flaking, scaling and itching of dandruff.  Studies shown it to be effective and better tolerated than selenium sulphide  Also has been shown as prophylactic agent in preventing relapse  Use every 3-4 days for up to 8 weeks, then PRN

Coal Tar  Affects

DNA synthesis and antimitotic effect  Effective, but not best choice  Disadvantages: - Unpleasant odour - Stain skin and hair - Folliculitis, allergic dermatitis - Photosensitivity

Various Treatment  Sulfur

2-5% - Keratolytic action - May also be combined with salicylic acid.  Tea tree oil (Melaleuca oil) - Trial of tea tree oil 5% vs placebo (n=126 patients) - Tea tree significantly better, however only 1 case complete response.

Evidence for Use 

 -

RCT comparing 4 anti-dandruff shampoos (n= 199 patients): Selsun Blue (selenium sulfide 1%) Head & Shoulders (zinc pyrithione 1%) Tegrin (coal tar) Flex Results: Selsun Blue showed greatest improvement in loose & adherent dandruff greatest rate of improvement P < 0.05

Prevention  Brush

hair daily.  Use hypoallergenic shampoo daily to control mild symptoms.  Wash hair at least 3 times a week.  Use anti-dandruff or anti-fungal shampoo once a week to prevent recurrence.  Nutrition: Include plenty of vitamin B in diet.

Summary  Pityriasis

capitis or dandruff is a common skin condition.  Etiology: increased cell turnover rate and yeast inhabitation  Treatment includes selenium sulphide, zinc pyrithione, ketoconazole and coal tar.  Patient education on prevention methods may be beneficial.

References 1.

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Rutter P. Community Pharmacy: Symptoms, Diagnosis and Treatment.Churchill Livingstone 2004. NHS Choices. Dandruff. Retrieved on 26th Aug 2009 from http://www.nhs.uk/Conditions/Dandruff/Pages/Introduction.aspx Pray WS. Dandruff and seborrheic dermatitis. Retrieved on 26th Aug 2009 from http://www.medscape.com/viewarticle/407641 Grimalt R. A practical guide to scalp disorders. Journal of Investigative Dermatology Symposium Proceedings (2007) 12, 10–14. doi:10.1038/sj.jidsymp.5650048 Rapaport M. A randomized, controlled clinical trial of four anti-dandruff shampoos. J. Int. Med. Res. 9 (2): 152–6