by Sara Malik*
Keywords: henna, hair, culture, plants, South Asia, contact dermatitis, dermatology
Henna is a dye that is prepared from the plant Lawsonia inermis that has been used for centuries to dye skin, hair, fingernails, and fabrics and can be found in hot climates. Henna has many useful properties as a cooling agent and anti-bacterial herb. The antimicrobial activity of henna is attributed to the free hydroxyls that can combine with carbohydrates and proteins in the bacterial cell wall; the hydroxyls may attach to and inactivate the enzyme sites of the microbes.1
The art of henna is a widespread cultural practice in countries in North Africa and South Asia. On weddings and holidays, women, and sometimes men, use henna paste to embellish their hands and feet with elaborate patterns. It can symbolize love, loyalty, prosperity, and fertility.
Furthermore, henna has been used as a natural hair dye by both men and women. It has been used to dye hair, beards, and mustaches, producing a range of colors. The colors range from orange on individuals that have a light hair color to deep burgundy on individuals that have a darker hair color. While allergic reactions to pure henna are rare, henna is sometimes mixed with paraphenylenediamine (PPD) to enhance the coloring effect, which can cause allergic contact dermatitis. There have been multiple cases reported of women presenting with allergic contact dermatitis to PDD after using henna hair dye, in which they developed facial and scalp swelling.2 With henna being increasingly popular in Western countries, it is important to be aware of additives in henna dye, that are common in Western countries, that can result in allergic reactions.
1Al-Rubiay KK, Jaber NN; Al-Mhaawe BH, Alrubaiy LK. Antimicrobial efficacy of henna extracts. Oman Med J. 2008;23(4):253-256.
2Redlick F, DeKoven J. Allergic contact dermatitis to paraphenylendiamine in hair dye after sensitization from black henna tattoos: a report of 6 cases. CMAJ. 2007;176(4):445-446. doi:10.1503/cmaj.061109.
Author Bio: Sara Malik is a second-year medical student at Northwestern University Feinberg School of Medicine in Chicago, IL. She is a first-generation medical student and is passionate about mentorship in medicine, public health, and cross-cultural medicine. Email: firstname.lastname@example.org