Lawson

Red, naphthoquinone dye from the group of ketones and naphthols, which is obtained naturally in a concentration of 1-2% from young branches and leaves of the dyer's shrub (also henna shrub), Lawsonia inermis.

For allergic skin reactions that appear shortly after the application of henna tattoos, it is considered probable that they are mostly caused by p-phenylenediamine that has been added for colour intensification ("black henna").

Lawason is stereoisomeric to juglone, an ingredient of the walnut shell that can be found in self-tanning products.

1. Almeida PJ et al (2012) Quantification of p-phenylenediamine and 2-hydroxy-1,4-naphthoquinone in henna tattoos. Contact dermatitis 66:33-37.

2. Boschnakow A et al. (2003) Temporary tattooing with henna induces contact allergy to textile dyes. JDDG 1: 962-964

3. Jovanovic DL et al.(2009) Allergic contact dermatitis fromtemporary henna tattoo. J Dermatol 36:63-65.
4. Polat M et al. (2009) Allergic contact dermatitis to pure henna. Dermatol Online J 15:15.