This page isn't designed to scare you off, just to make you aware of things you need to bear in mind when assessing products. However, in common with many readers, I am very concerned at the awful consequences for some people who have been exposed to what is commonly known as "black henna". I make no apology for including the photograph as it seems that milder warnings have not been getting the message across.
Disclaimer: As with the rest of this page, I must stress that I have not independently verified any of the information presented here. All I am doing is gathering together what I can find in amongst the mass of conflicting claims that surround this subject. If you can demonstrate that anything on this page is factually inaccurate, please contact us. I have also included a few opinions, which are entirely my own.
Known "black henna" problems - Full Story
The first thing to understand is that there is no such thing as black henna. Henna is the crushed leaves of the henna plant and gives an orange through brown stain. Any product that calls itself black henna is using an ingredient other than henna to achieve its colour.
The other thing I want to stress here is that if you've come to this page because you have just suffered a black henna reaction, please, please take yourself straight to a doctor. Don't just hope it will go away. Do post to the forum to let people know what happened, but not until after you've been to a doctor! Oh, and even if it itches - don't scratch! You'll increase the risk of permanent scarring.
While there are a few safe products out there, most "black henna" contains PPD, or p-Phenylenediamine to give it its full name. Found in many black hair dyes, this compound is known to cause chemical burns and severe allergic reactions in some people. The picture to the right gives you an idea of what this can mean for your skin. There is another photograph of the effect PPD can have at http://www.navel.com/mud/blackburn/ .
Allergic reaction to "black henna".
How to recognise PPD-based "black henna"
Even if you don't get a visible skin reaction to PPD, it can still be harmful. PPD penetrates deep into the skin, reaching the dermis (living cells) and passing into the blood stream. This is in contrast to henna, which only penetrates as far as the dead skin cells of the epidermis. Once in the blood stream, PPD can cause liver and kidney damage and exposure can lead to cancer of these organs. Breathing in PPD powder can cause lung damage, so those who prepare PPD-based black henna are at risk as well.
PPD is not the only ingredient used to make black henna. Some preparations are based on indigo, a plant material, though I personally have not seen evidence of how well this works or whether there are any problems associated with its use. Others tell me that the best you can expect from it is a blue-grey stain which lasts just a few days. There are also other chemical dyes in use, but none of them stains as fast or as black, or lasts as long as PPD. See the side-panel for guidance on how to recognise PPD-based black henna.
Of course, your skin might not react to PPD. But since the reaction can take three weeks or more to show, or in some cases appears only after a second exposure, it is not safe to assume that a 24 hour skin test is going to protect you. In any case, every time you expose yourself to PPD, you risk internal organ damage and increase your chances of getting cancer.
The International Chemical Safety Card recommends the wearing of protective gloves and protective clothing when handling PPD and warns "Exposure may result in death". Do you really want to put this stuff on your skin?
More information about PPD is available.
Pure henna powder has been in use for thousands of years and is hardly ever known to cause allergic reactions. However, as with all products which are applied to the skin, if you are uncertain, or know that you have sensitive skin, you should perform a skin test.
It is important to be aware that pure henna can only produce a orange/red/brown sort of colour.