The Science of Henna and Hair
 The Reference Library:
More coming soon!

Here are resources for more information on henna other natural hair dyes, synthetic dyes for hair, science, cultural aspects and history of hair.

Cultural and Historical Hair:

A looking-glasse for women, or, A spie for pride: shewing the unlawfulnesse of any outward adorning of any attire of haire, either in laying forth the haire, or in crisping of the haire, or in broidered haire in all women, but especially in godly women declared fully by the scripture : also those scriptures and carnall objections answered which are seemingly made for it
London : Printed for R. W., 1644

Comarum Akosmia: the loathsomnesse of long haire, or, A treatise wherein you have the question stated, many arguments against it produc'd, and the most materiall arguguments [sic] for it refell'd and answer'd : with the concurrent judgement of divines both old and new against it : with an appendix against painting, spots, naked breasts, &c. / by Thomas Hall
London, Printed for J.G. for Nathanael Webb and William Grantham 1654

Dreams of Trespass, Tales of a Harem Girlhood
Fatima Mernisi, Addison-Wellsley Publishing Co. 1994
Chapter 21 has Mernissi's wonderful story of hennaing hair and going to the hammam in Morocco!

Good and bad hair / photographs by Bill Gaskins
New Brunswick, N.J. : Rutgers University Press, c1997
Medicine, Law,  and Science

Hair: its power and meaning in Asian cultures
edited by Alf Hiltebeitel and Barbara D. Miller ; foreword by Gananath Obeyesekere
Albany : State University of New York Press, c1998
Includes: Hair and Society: Social Significance of Hair in South Asian Traditions / Patrick Ollvelle˜ 
                Hairy Barbarians, Furry Primates, and Wild Men: Medical Science and Cultural    Representations of Hair in China / Frank Dikotter 
                "Long Black Hair Like a Seat Cushion": Hair Symbolism in Japanese Popular Religion / Gary L. Ebersole 
                 Bound Hair and Confucianism in Korea / Sarah M. Nelson 
                 Politics of the Queue: Agitation and Resistance in the Beginning and End of Qing China / Weikun Cheng 
                 Hair Like Snakes and Mustached Brides: Crossed Gender in an Indian Folk Cult / Alf Hiltebeitel 
                 Living Ghosts: Long-Haired Destitutes in Colonial Hong Kong / James L. Watson˜ 
                 Cutting the Fringes: Public Hair at the Margins of Japanese Censorship Laws / Anne Allison 
                 Cuts and Culture in Kathmandu / Julia J. Thompson 
                 The Disappearance of the Oiled Braid: Indian Adolescent Female Hairstyles in North America / Barbara D. Miller

Hair matters : beauty, power, and Black women's consciousness / Ingrid Banks
New York : New York University Press, 2000

Lockin' up [videorecording] 
Nyame na oye Productions ; a story by T. Nicole Atkinson ; produced, directed and edited by T. Nicole Atkinson
New York, N.Y. : Women Make Movies [distributor], c1997

Medusa's hair : an essay on personal symbols and religious experience 
Gananath Obeyesekere
Chicago : University of Chicago Press, c1981

Off with her head!  the denial of women's identity in myth, religion, and culture
edited by Howard Eilberg-Schwartz and Wendy Doniger
Berkeley : University of California Press, c1995 
Includes: Untangling the Meanings of Hair in Turkish Society / Carol Delaney
              The Gendered Grammar of Ancient Mediterranean Hair / Molly Myerowitz Levine

The history of hair : fashion and fantasy down the ages
Robin Bryer
Publish info  London : Philip Wilson ; Wappinger Falls, N.Y. : Distributed in the USA and Canada by Antique Collectors' Club, 2000

Science, Law and Medicine of Hair

Evaluation of analytical methodologies for non-intrusive drug testing : supercritical fluid extraction of cocaine from hair 
Janet F. Morrison, principal investigator, Lorna T. Sniegoski, Wesley J. Yoo
Washington, DC : U.S. Dept. of Justice, Office of Justice Programs, National Institute of Justice, 1999

Henna and other Natural Hair Dyes

Natural ingredients for colouring and styling
Author: Dweck, A. C.a
Affiliations: a. Dweck Data, 8 Merrifield Road, Ford, Salisbury, Wiltshire SP4 6DF, UK
Blackwell Science, Ltd
Abstract: This paper examines some of the existing methods for colouring the hair and skin using natural material (such as henna) and proposes a parallel technology that exists in the dyeing of wool and fabrics to extend the colour range. Many of the listed plants and their derivatives are not found in Annex IV of the Cosmetic Directive and may not be used as colours; however, they do have other properties which may justify their inclusion into a product, for example, as astringent or anti-inflammatory agents. The paper concludes with some reported antigreying and hair styling preparations cited in the literature.

Indigo in the Arab World
Jenny Balfour-Paul, Curzon Publishing
Best book on indigo anywhere!!!!!  Balfour-Pauls glossier book, titled "Indigo", is also very good, though it's picture heavy and scholarship-lite.  . 

Synthetic Hair Dyes: 
Aniline and coal tar derivitives: Para-phenylendiamine and related chemicals

55 cases of allergic reactions to hair dye: a descriptive, consumer complaint-based study
Authors: S°sted, H.a; Agner, T.a; Andersen, K. E.b; MennÚ, T.a
Affiliations: a. The National Allergy Research Centre for Consumer Products, Department of Dermatology, University of Copenhagen, Gentofte Hospital, Denmark, and
b. Department of Dermatology, Odense University Hospital, University of Southern Denmark
Munksgaard International Publishers
Abstract: Severe facial and scalp dermatitis following the use of permanent hair dyes has been reported in several cases. Para -phenylenediamine (PPD) is known as a potent contact allergen, and PPD is allowed in hair dye at a concentration of 6%. Hair dye reactions are usually diagnosed by the patients themselves, and adverse reactions to hair dye may not necessarily be recorded by the health care system, unless the reactions are especially severe. Based on this assumption, we suspected that hair dye dermatitis was occurring more frequently than reported in the literature. Consumer complaint-based data were obtained by advertising for persons with adverse reactions to hair dye. Among those responding to the advertisement, 55 cases of severe, acute allergic contact dermatitis were identified. The main symptoms were severe oedema of the face, scalp and ears, and clinically this was often mistaken for angio-oedema. The 55 cases comprised a total of 75 visits to the health service and 5 admissions to hospital. 18 persons had sick leave, which supports the impression of very severe dermatitis reactions. 60% were treated with antihistamine, while 52% were treated with corticosteroids. 29% of the cases were patch tested and all were found positive to PPD. Our data presented here clearly show that PPD and its derivatives in hair dye at the present concentrations presents a significant health risk for the population. Furthermore, the severe acute allergic skin reactions are often misdiagnosed in the health care system. The frequency of allergic contact dermatitis resulting from hair dye is likely to be underestimated. New methods to survey the frequency of adverse reactions should be considered.

Cancer and coal tar hair dyes : an unregulated hazard to consumers
Report of the Comptroller General of the United States
Publish info  Washington : General Accounting Office, 1977

Cancer-causing chemicals
Hearings before the Subcommittee on Oversight and Investigations of the Committee on Interstate and Foreign Commerce, House of Representatives, Ninety-fifth Congress, second session ...
Publish info  Washington : U.S. Govt. Print. Off., 1978-

Dose–time relationships for elicitation of contact allergy to para -phenylenediamine
Hextall, J. M.a; Alagaratnam, N. J.a; Glendinning, A. K.a; Holloway, D. B.a; Blaikie, L.b; Basketter, D. A.b; McFadden, J. P.a
St. John's Institute of Dermatology, St. Thomas' Hospital, London, and
Safety and Environmental Assurance Centre, Unilever, Sharnbrook, Bedfordshire, UK
Munksgaard International Publishers
Abstract: Skin-sensitizing chemicals exhibit dose–response relationships for the elicitation of contact dermatitis. Previously, considerable work has been carried out in which the elicitation of allergic skin reaction has been examined as a function of the applied concentration. However, the relationship between exposure time, dose and response has not been explored in any depth. The present work has extended our initial assessment of the relationship between both exposure time and concentration for para -phenylenediamine (PPD) in a group of 19 PPD-allergic volunteers. The results clearly demonstrate that a relationship exists between both exposure time and concentration. Positive responses to PPD were directly proportional to exposure time: at 5 min 16% responded; at 15 min, 38%; at 30 min, 50%; and at 120 min, 69%. A similar direct relationship was found between concentration of PPD and response: after 120 min, 22% of patients had responded to 0.01%, and 69% to 1% PPD. All exposures for 1 and 2 min were negative. Subsequent evaluation using repeated 5 min open application testing demonstrated a cumulative effect, as after 8 days 39% of the panel reacted, more than double the number that reacted to a single occluded 5-min treatment. It was noted that there was marked subject variability in exposure time and dose required to elicit an allergic response. These results are of relevance for the general interpretation of patch test data, especially with regard to risk assessment.

Immediate-type hypersensitivity and allergic contact dermatitis due to para-phenylenediamine in hair dye
Wong, G. A. E.a; King, C. M.a
Department of Dermatology, Royal Liverpool University Hospital, Prescot St., Liverpool L7 8XP, UK  Munksgaard International Publishers

Positive patch-test reactions to para-phenylenediamine, their clinical relevance and the concept of clinical tolerance
Chan, Yuin-Chewa; Ng, See-Keta; Goh, Chee-Leoka
Munksgaard International Publishers
Abstract: 406 patients were patch tested over an 18-month period (January 1998 to June 1999) at a dermatology referral centre. 33 patients (8.1%) had a positive reaction to para-phenylenediamine (PPD). 20 patients were experiencing PPD hair dye dermatitis (present relevance, 61%), 2 were using PPD hair dyes without developing dermatitis (clinical tolerance, 6%), 4 had previously used PPD hair dyes with dermatitis in the past (past relevance, 12%), 3 had previously used PPD hair dyes without dermatitis (past exposure, 9%) and 4 had no known exposure to PPD (unknown relevance, 12%). Of the 20 patients whose test results were of present relevance, 17 avoided PPD hair dyes, resulting in total clearance of the dermatitis in all except 3, who had concurrent endogenous eczema. 3 continued using PPD hair dyes: 2 had recurrent contact dermatitis and 1 avoided dermatitis with meticulous technique. The 2 patients with clinical tolerance continued using PPD hair dyes with no dermatitis

Safety of hair dyes and cosmetic products
Hearing before the Subcommittee on Oversight and Investigations of the Committee on Interstate and Foreign Commerce, House of Representatives, Ninety-sixth Congress, first session, July 19, 1979
Publish info  Washington : U.S. Govt. Print. Off., 1979 i.e. 1980

The risk of active sensitization to PPD
Devos, Steven A.a; van der Valk, Pieter G. M.a
Department of Dermatology, University Hospital Nijmegen, The Netherlands
Munksgaard International Publishers
Abstract: Para-phenylenediamine (PPD) and para-aminoazobenzene are strong sensitizers. By the patch test procedure, the patient may be sensitized to these agents. Combined testing of para-compounds may increase the risk of active sensitization.