Dandruff and seborrheic dermatitis adversely affect hair quality

ARTICLE

Auteur(s) : Rodney D Sinclair¹, James R Schwartz², Heather L Rocchetta², Thomas L Dawson Jr³, Brian K Fisher³, Knut Meinert⁴, Elizabeth A Wilder³

¹Department of Dermatology, St. Vincent’s Hospital Melbourne, University of Melbourne, P.O. Box 2900 Fitzroy Victoria Australia 3065
²Sharon Woods Innovation Center, The Procter & Gamble Company, Cincinnati, Ohio, USA
³Miami Valley Innovation Center, The Procter & Gamble Company, Ross, Ohio, USA
⁴Darmstadt Technical Center, The Procter & Gamble Company, Darmstadt, Germany

Dandruff/seborrheic dermatitis (D/SD) is a common chronic inflammatory condition. Inflammation, possibly initiated by microflora such as Malassezia sp., results in flakes, erythema and itch. The impact of D/SD on associated hair has not been studied previously; we report the results of evaluations of hair from a D/SD population in comparison to a control group.

Female volunteers providing informed consent from the Xi’an region of China with a hair length of at least 12 cm and who had refrained from use of an antidandruff shampoo, hair colorant and permanent treatment for at least one year were considered for inclusion. Based on expert dermatologist grading of D/SD severity (adherent scalp flaking score, ASFS [1]), women were classified as affected (ASFS ≥ 27) or controls (ASFS ≤ 15). Hair was cut from a 2.5 cm² area (for the D/SD group it was from the highest flaking area). This area was then clipped to about 1 mm hair length prior to imaging using a Hi-Scope system. Objective image capture and analysis methodology [2] provided hair diameter as well as growth rate via image acquisition, initially and 24 hours post hair-clipping. Isolated hair was gently but thoroughly washed prior to subsequent blinded assessments. Surface hardness was assessed by a slight modification of a nano-indentation technique [3]. Shine was assessed [4] by evaluation of the height and full width at half maximum (FWHM) of the shine band; the more narrow the band, the more intense the shine.

Population parameters and experimental data are summarized in table 1. The D/SD group exhibited a reduced hair diameter compared to that of the normal subjects (p-value 0.068). The hair derived from D/SD scalp was significantly (p: 0.027) less shiny than hair from normal scalp. Finally, using the nano-indentation technique, the surface hardness of hair was found to be harder (p: 0.08) for D/SD hair than normal hair.

These observations indicate for the first time that D/SD symptoms extend to hair quality as assessed by objectively-measured shine and supported by directional changes in diameter and surface hardness. The higher surface hardness may encourage superficial damage that results in reduced shine. While this study was limited to one gender and ethnic group, we feel these results are generally relevant based on analogous observations in psoriasis and lead to a broader and more complete description of D/SD symptoms.

Psoriasis is also a chronic inflammatory condition with similar cutaneous symptoms to D/SD; negative effects on associated hair have been described. Hair from psoriatic scalp areas tends to be abnormally narrow and has surface irregularities such as micropits and abraded cuticle surfaces ([5] and references therein). These independent observations in D/SD and psoriatic conditions suggest that, in general, chronic inflammatory scalp conditions affect the associated hair as well as the skin.

While there is no specific data available determining the impact of scalp atopic dermatitis (AD) to hair, it is possible, based on the role of nonspecific immunity to Malassezia in this condition [6], that scalp AD also causes negative hair manifestations.

We hypothesize that the similarities between the skin and hair symptoms of psoriasis and D/SD are due to common pathogenic pathways involving chronic inflammation. Psoriasis is thought to result from an exaggerated immune response to an unknown skin autoallergen and D/SD an immunological response to increased skin colonization by Malassezia sp. On histology, both conditions display chronic dermal inflammation, irregular psoriasiform acanthosis, hypogranulosis, and parakeratosis, resulting in many similarities. We have demonstrated in this work that the hair quality effects of both conditions are qualitatively similar. This is represented schematically in figure 1. While hair loss may occur in association with scalp psoriasis [5, 7] further research is needed to ascertain whether the common pathogenic pathway with D/SD leads to enhanced hair loss rates for D/SD sufferers as well.

Acknowledgements

References

2 Berger R, Fu J, Smiles K, et al. The effects of minoxidil, 1% pyrithione zinc and a combination of both on hair density: a randomized controlled trial. Br J Dermatol 2003; 149: 354-62.

3 Wei G, Bhushan B, Torgerson P. Nanomechanical characterization of human hair using nanoindentation and SEM. Ultramicroscopy 2005; 105: 248-66.

4 Sendelbach G, Haller M, Springob C, Schmidt H. Hair lustre measurements via image analysis and its use for cosmetically altered hair. In: 12th International Hair-Science Symposium. Heidelberg, Germany, 2001.

5 Kumar B, Soni A, Saraswat A, Kaur I, Dogra S. Hair in psoriasis: a prospective, blinded scanning electron microscopic study. Clin Exp Dermatol 2008; 33: 491-4.

6 Ashbee H, Evans E. Immunology of diseases associated with Malassezia species. Clin Microbiol Rev 2002; 15: 21-57.

7 Shuster S. Psoriatic alopecia. Brit J Derm 1972; 87: 73-7.