Since the first grey hair appeared on the head of a hip cave chick, we women (and lots of men) have been colouring our hair and fretting over keeping the colouring a secret. Technology, that amazing animal that makes things quicker, better, faster and easier, has not left the field of hair colour unscathed. Chemicals have been replicated, split, and recombined to create more colours, brighter colours, longer lasting colours and faster colouring times. Some chemicals, as we all know, are delightful- the molecules in chocolate (and other happiness inducing treats) bind with receptors in our brain and all is bliss. Other chemicals are neither so bliss inducing nor are they safe. 

p-Phenylenediamine (PPD) is an aromatic amine compound used in almost every hair colour dye on the market, regardless of brand. The darker the colour, usually, the higher the concentrations. Even the so-called "natural" and "herbal" hair colours, while ammonia-free, contain PPD. (Psst, ammonia is a natural by-product! PPD is neither natural nor essential!!) So, really, what's the big deal? Medicines are advanced due to increased knowledge of synthesizing chemicals and trimming them down to their finest abilities, doesn't that mean hair colour has to be as advanced and as safe as the world of medicine? To put it simply, no.

Most of us that use henna as body art well know the issues associated with PPD mixed with henna, but many people out there using hair dye have no idea what is in the hair dye that causes them to break out, itch and suffer redness all over the head and neck every time they colour their hair. Or they do and due to a lack of alternatives, continue to suffer.
 

What is PPD and what is its connection to henna?

PPD is the main allergen identified in allergic reactions to decorative skin paintings.22   Para-phenylenediamine is a colourless/slightly pink, grey or yellow crystalline solid (lumps or powder). On oxidation, usually through exposure to air, it turns red, brown then finally black. PPD is essentially a dye and chemical intermediate.3   It may also been [sic] found in textile or fur dyes, dark coloured cosmetics, temporary tattoos, photographic developer and lithography plates, photocopying and printing inks, black rubber, oils, greases and gasoline.4   PPD is a low toxicity diamine used as a component of engineering polymers and composites, aramid fibers, hair dyes, rubber chemicals, textile dyes and pigments. PPD is selected for the outstanding properties it imparts, including high temperature stability, high strength, and chemical and electrical resistance.18 

Some particularly atrocious misinformation twists have led to PPD being described as a black mineral from the banks of the River Nile. This gives PPD an undeserved distinction as being both natural and exotic. Obviously, anyone who proposes this myth, knowing its falseness, is not only lying, but purposefully harming people.  PPD gained infamy from being an ingredient, used either pure or as an “additive” to henna, to create or give henna a black tattoo-like appearance. This is due to the ‘fad’ quality of henna as a temporary tattoo. Traditional artists and traditionally trained artists are aware that the words “henna” and “black” do not go together:
 

“Henna gives an orange/reddish-brown stain. Any product that calls itself black henna  must contain an ingredient in addition to pure henna to achieve its ebony color. In most cases, this added ingredient is PPD, that is also found in many black hair dyes. Another reason for using PPD additives is to speed up the tattooing process. While traditional henna staining takes 2-12 hours, a pure black tattoo can be achieved within an hour or two with the addition of PPD, and there will be a longer lasting effect as well. 

The findings of a mass spectrometry analysis of commercial black henna performed by Chung et al. demonstrated a major peak at the mass-charge ratio of 108.1, which corresponds exactly to the molecular weight of PPD. There was no line at the molecular weight 174.2, that of the active agent of pure henna. This was the first sophisticated, scientific proof of what almost every tattoo artist or supplier had known for years.” 1

In other words, there is no such plant as or plant that gives “black henna” and here we see scientific proof that it is the chemical called PPD that makes this phenomenon. It’s nothing to do with henna at all, other than a piggyback ride from a legitimate and healthy art form turned into a marketable and highly profitable scheme that harms people. Luckily, there are people speaking out on this to make the people who manufacture, sell and use PPD to be held liable for what they are doing.

An important factor to remember about PPD is that it is cheap. You can buy very cheap black hair dye and mix it with henna (or use it pure if you are that much of a @#$%!) and make lots of money. However, caveat emptor to anyone reading this with ulterior motives- I can guarantee you won’t make enough to cover your butt when you are sued. 

Honestly, what is so wrong with it? 
I mean, reputable companies use it, right?

Many phenylenediamines are demonstrated to be mutagenic and carcinogenic per numerous studies.16   Mutagenic, as defined by http://www.thefreedictionary.com: capable of inducing mutation (used mainly of extra cellular factors such as X-rays or chemical pollution.) At its most innocent, PPD might inflict a person with a nasty welt-like reaction that itches and burns. At its most malignant, PPD has been associated with death. Yes, you read that right: death. 
 

“We present a patient with rhabdomyolysis dermatological findings and  renal failure that occurred after use of a commonly available hair dye preparation. This 41 year old woman … approximately 1-2 weeks prior to the admission, she dyed her hair for the first time in her life … Shortly thereafter, she noticed itching and pain near her hairline. This was followed by blistering of the skin in this area and then lesions on the neck, interior chest and abdomen. There were no other risk factors for rhabdomyolysis in her history. Para-Phenylenediamine is the ingredient in the hair dye that has been associated with rhabdomyolysis … Although absorption through the skin apparently can cause local skin reactions, a life-threatening occurrence as described above is not well known.” 2

Please note the last line. Life threatening occurrences are not well known. Some people will use the rarity of dangerous situations to defend the use of PPD in their product. Some marketers and “appliers” (‘black henna artist’ would have to be a misnomer of sorts!) prefer to tell clients that mild reactions are common and no big deal. They recommend an anti-itch cream, but blow it off as no big deal. They fail to mention the sensitization issues. This is ignoble and serves to prove the point that the use of PPD is purely to market something with no respect for the people who use it nor any care for what might happen to them. Though not an uncommon viewpoint in the capitalist mindset, it isn’t something that people in the know are going to let slide. This issue not about cosmetic and technical grades- it is about a substance that does more harm than good when used in an illegal and uncontrolled manner and the public should be informed as to the extent of the harm. Not to mention the fact that PPD is neither promoted for use on the skin or legal to use on the skin! 

The issue needs to be brought to the forefront- and it appears that the connections between hair dye and cancers are getting attention. As attention as  was brought to PPD being combined with hair dye to create “black henna,” we hope that attention will be focused on the PPD itself- at least to the point of perhaps of offering alternatives to those sensitized to PPD, and those avoiding PPD. More focus on traditional dyeing practices would be ideal as well. In regards to henna used with PPD- to manufacture hair dye is one thing. To buy hair dye, mix it with henna and market it as something that does not exist, that’s different! 

Even DuPont, makers of PPD, warn against using it on the skin.18   Would you buy medicines mixed from someone down the street? Of course not! But “black henna” manufacturers do exactly this. To know the whole story one needs to know exactly what PPD is and why it isn’t even completely safe in its regulated field- only when one knows the full story can one make an informed decision. Connections, even tenuous ones, between PPD and dangerous, life threatening consequences are not to be taken lightly!
 

A 27-year-old Japanese man with no past history of liver disease was admitted to our hospital due to liver abnormalities. The patient was diagnosed with drug-induced hepatitis, as the three episodes of hepatitis occurred just after repeated use of hair dye. After cessation of the hair dye use, abnormal liver function tests improved to within the normal range. Although hair dyes contain various hepatotoxic compounds, hair dye is not known to cause drug-induced hepatitis. Thus, in cases of liver abnormality of unknown origin, the history of hair dye use should be investigated.13

Over the past few years there has been much discussion amongst lichenologists concerning the dangers inherent in using para-Phenylenediamine. It is known to be carcinogenic but recent evidence seemed to suggest that the dangers were remote and that it was only a very weak carcinogen. However, the latest work on this compound indicates that it should be treated by lichenologists with great care. Articles in The Times (January 6 and 22) and the British Journal of Dermatology emphasise the inherent dangers of para-Phenylenediamine. An especial danger is present in its easy absorption through the skin. A study in the United States found that people who used this, or similar products, as permanent hair dye can triple their risk of bladder cancer. 14

What happens to people who use it?

The CDC lists p-Phenylenediamines as being known as one of many contact allergens. The NIOSH Pocket Guide to Chemical Hazards lists exposure routes as through inhalation, skin absorption, ingestion, skin and/or eye contact. Symptoms listed are: Irritation pharynx, larynx; bronchial asthma; sensitization dermatitis. 

There seems to be a small misconception that you will react immediately to PPD, so if it doesn’t burn/sting or otherwise present an effect immediately, one is safe from any reaction. This is not true and it’s a dangerous myth! PPD is known for its short sensitization period- that means you might not get or see an immediate reaction, but the next time you get a “black henna” tattoo or otherwise come in contact with PPD you could have an extremely bad reaction. PPD elicits not only contact hypersensitivity but immediate-type hypersensitivity.10

Not only that, but the sensitization issue seems to be much larger for another little known reason: Subjects have been shown to react to lower concentrations of metabolic breakdown products of PPD than to the actual PPD molecule itself.21   In the simplest terms, this means that PPD breaks down in your body in a sort of digestive process. These smaller amounts are more sensitizing than the actual PPD is when it first comes in contact with you! That’s probably a notable factor in the sensitizing issue. As it breaks down, it is, in effect, stronger and more likely to cause cross sensitizations with other products, including but not limited to PABA based sunscreen that people wishing to prevent skin cancer often use.
 

“Another important issue that should be addressed is the very short sensitization period  involved. In our cases of temporary tattoo reactions, as well as in many other reported ones, it took 3 to 4 days for the reactions to develop. It is generally accepted that the induction of allergic contact dermatitis takes at least 7-10 days when a new antigen is introduced.” 1

Even those who market “black henna” and PPD as completely safe warn consumers who get a reaction to never use the stuff again. That’s because sensitization is a life long issue. The application of PPD may lead to active sensitization to black clothing, printer's ink, Fax ink, hair dye, fur dye, leather dye, and photographic products.9  You may also have to avoid the following:
 

PABA-based sunscreens or creams, Azo® or disperse textile dyes, other dye chemicals, Sulfa drugs, semi permanent hair dyes, some “caine” drugs such as benzocaine,  sulfonamides,  Para-aminosalicylic acid (p-aminosalicylic acid),  diaminodiphenylmethane (epoxy hardener), para-aminodiphenylamine (p-amino-diphenylamine),  paratoluenediamine (p-toluenediamine),   2,4-diaminoanisole,  ortho-aminophenol (o-aminophenol),  black rubber products,  and sulfones.

The crazy part is that unless you are intimately knowledgeable about the manufacture of these products you may not even know when you are coming into contact with a potential unsafe product! And make no mistake, this isn’t as simple as “don’t apply black henna” or “don’t use hair dye too much” – it’s a matter of not ever breathing/touching/wearing/working with/using these substances or anything used with them again! That’s what they mean by the phrase contact dermatitis. 

The instant of contact creates a reaction. p-Phenylenediamine hair dye dermatitis is common in Singapore. PPD  hair dyes are preferred for colouring, as they impart a long-lasting jet-black colour.5  PPD is a potent skin sensitizer; it can cause angio-neurotic edema, collapse, and renal failure in severe cases.6 Severe cases of immediate type hypersensitivity to PPD described in which the patients developed severe edema, irritation of the eyes and face and also difficulty in breathing.7   p-Phenylenediamine has been reported to increase the formation of liver tumors in mice. 8  Numerous MSDS report that repeated and/or prolonged exposure can cause asthma. Acute exposure to high levels of p-Phenylenediamine may cause severe dermatitis, eye irritation and tearing, asthma, gastritis, renal failure, vertigo, tremors, convulsions, and coma in humans.29

Yes, I know, you are thinking, well I’m not going to inhale it all the time and I don’t colour my hair all the time. Would you inhale just a little toxic gas coming from an industrial waste company? No?! It’s “ok” if you just do it once or twice… 

Now, I know you aren’t going to try eating or otherwise consuming hair dye. You probably know you aren’t either. But I bet you aren’t going to consume bug spray or anti-freeze either, right? Children sometimes do, and that makes this important: 
 

"Poisoning by a mixture of henna dye and para-phenylenediamine dyes led to the hospitalization of 31 Sudanese children between 1984 and 1989. There was a characteristic clinical presentation. All children presented with an acute and severe angioneurotic oedema and 15 of the cases required emergency tracheostomy for respiratory obstruction. Acute renal failure occurred in five children who recovered after peritoneal dialysis. Mortality was high, all 13 deaths occurring within 24 hours of presentation. Hypotensive shock gave a poor prognosis. It is possible that similar cases may be occurring unrecognized where henna is traditionally used. A programme of public education and restriction of para-phenylenediamine is urgently required in The Sudan and other affected nations. Ingestion was accidental in 12 children, deliberate in 10 and homicidal in three cases. Cutaneous absorption was likely in the remaining six."12

The other thing it can do is leave your career choices limited! Don’t think of becoming a hairdresser. You’ll also have to avoid contact with everything that PPD sensitizes to. Believe it or not, that’s a wide arena that also includes rubber, leather and textile dyes, among many industrial jobs. After the blisters and welts heal, that’s a final blow:
 

"On contact with the skin a cleavage of the molecule at the azo bridge occurs. One of the fragments produced is PPD. Thus, young people must shelve the idea of some profession where they cannot avoid contact with PPD." 17

Beyond that, you know it’s bad when lawyers get involved. The Nottingham based Associated Personal Injuries Lawyers issued an August 2003 press release warning women of hair dye chemical risks:
 

“Although serious adverse reactions to PPD are relatively rare, anyone using dyes containing this chemical should be aware of the risks. Yet how many women have even heard of PPD, let alone know enough to be wary of it? … Backing APIL’s campaign to raise awareness of the risks associated with PPD, Mrs. Walker [trichologist and expert witness] called for hair dye packaging and manufacturers’ literature to specify very clearly the adverse signs to look for when actually applying the dye to the hair. And she stressed: ‘It is so important that anyone using hair dye carries out tests for sensitivity every time they use them.’” 25

APIL member Alan Care is particularly concerned about the possible effects of PPD and calls for box labeling on products containing PPD and wishes to see more pressing information about sensitivity testing in the instruction leaflets enclosed. In the press release he speaks of one claim involving an adverse reaction so severe that doctors suspected a tropical disease and the client was placed in an isolation ward.25
 

Does it hurt everyone or just some people?
 

We experienced 38 cases of beauticians with occupational allergic contact dermatitis in a 4 year 7 month period from January 1990 to September 1994. We diagnosed them based on their past histories, onset situations, clinical features and patch test results. The subjects included 7 males and 31 females. Twenty (53%) of the 38 cases developed their skin disorders within 3 months after beginning their jobs. Thirty five out of 38 cases were patch tested with products used and allergens relevant to their occupation. … Fifteen cases out of 29 tested showed allergic reactions to hair dye products. As to ingredients of hair dye products, oxidative dyes such as para-phenylenediamine (PPD)…  reacted frequently : PPD caused positive reactions in 27 (79.9%) out of 34 tested. 15

No, PPD doesn’t hurt everyone, just like cigarettes don’t cause all smokers to get cancer. This question is misleading- especially with a younger audience who share a mindset of absolutes- if it doesn’t hurt *every* one then it probably won’t hurt me! The point is, PPD is not regulated for use on the skin and certainly not in its purest forms. When you buy henna that is laced with PPD you are not getting something that is regulated to be a standardized amount in every single box. In fact, you might be getting something that is far more concentrated than the box of hair dye you are trying to get away from. Out of the frying pot, into the pan. Take the guesswork out of deciding whether PPD will harm you, your clients or your friends: avoid it entirely and then you’ll know that it won’t. 

As women, we are well acquainted with the concepts of suffering for beauty. Many women will suffer if they think they will get even a small percentage of positive results later. There are those that continue to use PPD based dyes, even knowing that it is the culprit for their reactions. When it comes to hair colour itself, it doesn’t always affect everyone in a negative manner, but those whom it does affect, usually continue to use the product irregardless:

 
“… She took great care to minimize contact with her scalp. With these precautions she was able to continue dyeing her hair without problems. However, on those occasions when she happened to miss any one of the precautionary steps, she would develop a pruritic eczematous rash within a day.”5

Every time they colour, these people put themselves at risk for countless PPD reactions. PPD can cause angioneurotic edema, collapses and renal failure in severe cases.23   And that’s just what it is doing in this generation- what happens down the road as more people are sensitized to PPD?  In one study it was found that 2-methoxol-p-phenylenedyamine, a component of oxidative hair dyes, causes necrosis of skeletal muscle (gastroenemius, diaphragm and tongue) in rats.24

Simply put, "commercial hair dye products are known to cause hypersensitivity in certain individuals and several mutagenic phenylenediamines (PPD) found in hair products have been reported to be carcinogenic in animals.”19  Not to branch off into linguistics, but the passive voice construction up there, “are known to cause” is a commonly used grammatical device to shift focus, and often blame. Back on track, it’s not much different than cigarettes, really. 
 

Co-sensitizations to para-phenylenediamine were present in most subjects sensitized to DO3 (Disperse Orange 3) at 66% and PAAB at 75% … Apart from the hands and the face, the neck and the axillae were the most frequently involved skin sites. … in patients with hand dermatitis and in those working as hairdressers, sensitization to DO3 and PAAB was more frequent.”20 

If it is so bad, why is it out there?!

This is such an innocent question, that it’d be cute if it weren’t for the naïveté and potential to harm behind it. Unhealthy products are sold freely everyday. 
 

“Sensitization by para-phenylenediamine(PPD) has been considered by some countries to be so great a hazard that its use in hair dyes was banned in Germany in the early 1900’s.  It was subsequently prohibited in France, and in 1964 in Sweden; however in Japan PPD is still used as a common component in hair dyes.”

We sip diet cokes that deplete our bones of calcium, we smoke cigarettes that destroy our lungs, we eat cookies that are full of fats that prevent our systems from operating properly, we spray chemicals on our yards that mimic hormones and create havoc in yet to be born children, we breathe fumes that destroy our brain cells and we imbibe liquids that course through our blood wreaking havoc upon every cell they touch. This knowledge doesn’t stop us from doing things we know to be bad for us. It also doesn’t stop manufacturer’s from selling a “quality” product! 

The fact is that everything that is out there that is bad for us puts money in someone’s pocket. That’s why that someone put the product out there for use. They deny that it could be harmful as that would stop the money from coming in! Instead of wondering why such bad things happen, spend your time getting informed about everything. From bad cookies, to alcohol to hair colour- it’s up to you to decide what you’ll do with your body, your time, your life and your money. 

Summary

Now you know the story behind PPD- you know it’s an unsafe substance, though mostly regulated. If you are using hair colour and having reactions, stop already! If you aren’t, you might still want to rethink the stuff.  It’s not necessary for colouring your hair, so there is no reason to use it- certainly not if you are already sensitized and react every time you do use it. 

How on earth then are you to colour your hair? There are so many ways! Let this website tell you! First, there is a reason so many people out there have dried out, broken off, falling out hair. They expose it to elements and harsh chemicals and don’t take proper care of it. Elements are a whole different story, but chemicals aren’t. Hair care and colouring is basically simple. In a world of technological advancement occurring every half hour, we want the most complex things out there. But the basics worked for millennia before the synthetic chemicals and will continue to do so. 

Take a look at the pics on this site of hair that is thick, healthy and glossy and commit to changing your ways and your tresses!

Appendix

Alternative names for para-phenylenediamine:

PPD or PPDA, Phenylenediamine base, p-Phenylenediamine, 4-Phenylenediamine, 1,4-Phenylenediamine, 4-Benzenediamine, 1,4-Benzenediamine, para-Diaminobenzene (p-Diaminobenzene), para-Aminoaniline (p-Aminoaniline), Orsin™, Rodol™, Ursol™, 2 - Nitro - 1,4 - diaminobenzene, Dye GS, Durafur Brown 2R, Fouramine 2R, 1,4 - Diaminonitrobenzol (German), 1,4 - Diamino - 2 - nitrobenzene, C.I. Oxidation Base 22, Fourrine Brown 2R, NCI - C02222, 4 - Amino - 2 - nitroaniline, 2 - Nitro - 1,4 - benzenediamine,  Fourrine 36, o - Nitro - p - phenylenediamine, 2 - Nitro - 1,4 - phenylenediamine, Nitro - p - phenylenediamine, 2 - Nitro - p - phenylenediamine, Oxidation Base 22, Ursol Brown RR, C.I. 76070, Zoba Brown RR, 2 - Nitro - 4 - aminoaniline,

Chemical information: 

Formula:4-Phenylenediamine base - C6H8N2 
Cass number: 106-50-3 
Cross reactions: Azo and aniline dyes, Benzocaine, Procaine, Para-aminobenzoic acid (PABA), Para-aminosalicylic acid, Sulfonamides, Carbutamide, HydroDIURII 
Appearance: White to slightly red solid crystals that darken on exposure to air. 
Sensitizer: intermediate, partially oxidised PPD 
Patch Test: 2% PPD in petrolatum 
 

Bibliography & Works Cited:

Personal experience with hair dye and henna

1 Wolf, MD, Ronni; Wolf MD, Danny; Matz, Hagit; Orion, Edit. “Cutaneous Reactions to Temporary Tattoos” Dermatology Online Journal

2 Lava, N.S; Dollar, J. “Hair dye-induced rhabdomyolysis” Albany Medical College, Albany, NY

3 Farrow, Catherine. “Hair Dye and Henna Tattoo Exposure” Emergency Nurse, Jun2002, Vol. 10 Issue 3, p19, 5p
 In addition to local effects, there is the risk of systemic toxicity. Transcutaneous absorption of PPD is rapid and may lead to systemic effects including angioedema, gastro-intestinal disturbances, tremors, drowsiness, convulsions, dyspnoea, liver atrophy, acute renal failure, cardiac arrest and death (Brown et al 1987, Yagi et al 1991, Abdulla and Davidson 1996). However, systemic effects appear more likely to develop following chronic topical application. Ingestion Although there is some dose-effect relationship, it is not clear if hypersensitivity and sensitisation reactions are the major contributing factors to morbidity from oral exposure to PPD. There are two phases of toxicity following PPD ingestion (Shemesh et al 1995). Phase 1: The onset of effects is usually within four to six hours after ingestion. The more severe the poisoning, the earlier the onset of effects (Chugh et al 1982, Suliman et al 1983, Yagi et al 1991). Effects include numbness and 'burning' of the mouth and throat; epigastric pain and gastritis, persistent vomiting (vomitus may be brown), which may lead to dehydration. Angioedema, rapid, progressive swelling of the lips, tongue (which may be protruding and wooden-hard), face, eyes, oropharynx and neck develops. This swelling may lead to upper airway obstruction with dysphagia, respiratory distress or failure and cyanosis, exophthalmus (protrusion of eyeball) and/or optic neuritis and permanent blindness. Phase 2: The onset of effects is usually within the first 12 hours after ingestion (Suliman et al 1983), if Phase 1 is survived, and may be prolonged for several weeks (Yagi et al 1991). Effects include dark urine (a characteristic chocolate or reddish brown colour), oliguria or anuria, acute tubular necrosis and acute renal failure. Muscle pain and tenderness, rigidity, rhabdomyolysis, intravascular haemolysis and drowsiness may also occur. ECG changes may include tachycardia, QRS prolongation, and tall, tented T-waves (Chugh et al 1982). Mild pyrexia, hepatitis, convulsions, coma, bronchopneumonia, and sudden cardiac arrest are less frequently reported. Hypotensive shock and irreversible ventricular fibrillation are associated with a poor prognosis (Ashraf et al 1994). Death usually occurs within 24 hours post-ingestion and may be caused by airway obstruction, acute renal failure or cardiac arrest. Blood analyses may reveal abnormalities including raised serum osmolality, hyperkalaemia, methaemoglobinaemia, creatinine kinase, haemoglobinaemia, increased plasma urea concentration (usually peaks three days post-ingestion), and metabolic acidosis. Also, raised serum ALT and LDH (lactate dehydrogenase), anisocytosis and poikilocytosis (erythrocytes of variable size and shape, respectively). Urinalysis has revealed raised urine osmolality with proteinuria, haematuria, haemoglobinuria, myoglobinuria and albuminuria (Chugh et al 1982, Suliman et al 1983, Averbukh et al 1989). Ocular exposure PPD causes mucous membrane irritation with lacrimation, but no caustic or injurious effects are anticipated unless the individual is hypersensitive to it (Grant and Schuman 1993). As with other routes of exposure, hypersensitivity is spontaneously present in some individuals and readily developed in many others. Acute inhalation Inhalation of PPD may cause asthma attacks, bronchospasm, and inflammation of the pharynx and larynx. These effects are more usually as a result of sensitivity reactions following previous exposure(s) to PPD. Chronic dermal exposure Lethargy, myalgia, purple-ish discoloration of gums and teeth, anorexia, gastro-intestinal disturbances, liver and spleen enlargement, subacute atrophy of the liver, jaundice, chronic renal failure, progressive neurological symptoms and coma have all been attributed to chronic exposure to PPD (Yagi et al 1991).

4 Ngan, Vanessa. “Allergy to Para-phenylenediamine” http://www.dermnetnz.org/index.html 

5 Chan, Yuin-Chew; Ng, See-Ket; Goh, Chee-Leok. “Positive patch-test reactions to para-phenylenediamine, their clinical relevance and the concept of clinical tolerance” National Skin Centre

6 Abdulla KA, Davidson NM. “A Woman who Collapsed after Painting Her Soles” Lancet 1996: 348: 658 

7 Calman, CD. Hair Dye Reaction “Contact Dermatitis” Newsletter 1967; 1:16 

8 Chung, K; Murdock, C; Stevens, S; Li, Y; Wei, C; Huang, T; Chou, M. “Mutagenicity and Toxicity studies of P-Phenylenediamine and its derivatives” Toxicology Letters 81, 1995, 23 - 32 1995 

9 Devos, Van Der Valk. “The Risk of Active Sensitization to PPD Contact Dermatitis” 2001, 44, 273 - 275 Department of Dermatology, University Hospital Nijmegen, The Netherlands 

10 Edward EK Jr; Edward EK. “Contact Urticaria and Allergic Contact Dermatitis caused by Paraphenylenediamine” Cutis 1984, 34: 87-8 
"PPD elicits not only contact hypersensitivity but imediate-type hypersensitivity.10

12 Hashim S; Hamza Y; Yahia B, Khogali F; Sulieman G. “Poisoning from Henna Dye and Para-phenylenediamine Mixtures in Children in Khartoum” Annals of Tropical Pediatrics 12, 3 - 6 

13 Tokumoto Y; Horiike N; Onji M; Ueda T; Kumagi T; Abe M; Michitaka K. “Drug-induced hepatitis due to repeated use of hair dye” Third Department of Medicine, Endoscopy Center, Ehime University School of Medicine, Ehime.

14 Dobson, Frank S. “The Problems and Dangers of Using Para-Phenylenediamine” http://users.argonet.co.uk/users/jmgray/pdprob.htm British Lichen Society

15 Yoshimi Kato Ritsuko;  Hayakawa Mari Suzuki. “Occupational contact dermatitis in beauticians” Environ Dermatol 4 :25-29, 1997 

16 Ames, B.N; Kammen, H. O; and Yamasaki, E. “Hair Dyes are Mutagenic: Identification of a Variety of Mutagenic Ingredients” Proc. Natl. Acad. Sci., USA, 72, 2437 - 2433  1975 

17 Hausen, Professor Bjorn “Henna/p-Phenylendiamin-Kontaktallergie: Folgenschwere Dermatosen nach Henna-Tätowierungen” Dermatological Research Centre, Germany http://www.aerzteblatt.de/v4/archiv/artikel.asp?id=27955

18 DuPont website http://www.dupont.com/specintermediates/ppd.html
 DuPont does not recommend and will not knowingly offer or sell p-phenylenediamine (PPD) for uses involving prolonged skin contact. Such uses may involve, but are not limited to, products formulated with henna for tattoo applications or other skin coloration effects. This use of PPD in prolonged skin contact application has the potential to induce allergic skin reactions in sensitive individuals.

19 Al-Tufail, M; Mahier, T; Tate, J; Haq, A. “Rapid Identification of Phenylenediamines in Traditional Hair Dyes by Gas Chromatography-Mass Spectrometry” Department of Pathology and laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia 
 Ten samples of commercial hair dye had an average p-PD level of 7.7% with individual samples ranging form 0.04 to 66.5%.

20 Seidenari S; Mantovani L; Manzini B.M; Pignatti M. “Cross-sensitizations between azo dyes ansd para-amino compound” Department of Dermatology, University of Modena Contact Dermatitis 1997 36/2 91-97 – summary
 Cross-sensitizations between azo dyes and para-amino compounds can partially be explained on the basis of structural affinities.

21 Blohm SG; Rajka G. “The Allergenicity of Paraphenylenediamine Acta Dermatolo-Venercologica” 1970: 50: 51-4 

22 Nikkels, AF; Henry, F; Pierard. Allergic Reactions of Decorative Skin Paintings” European Academy of Dermatology and Venereology,  2001 15, 140-2 

23 Le Coz, C.J. “Risques des peintures cutanées ou tatouages labiles au «henné noir»” Revue Francaise d'Allergogie et d Immunologie Clinique Volume: 41, Issue: 5, August, 2001. pp. 504-509. 

24 Munday R; Manns E. “Muscle Necrosis in Rats Induced by 2-Methoxy-p-phenylenediamine” Food and Chemical Toxicology 37 1999 561-564 

25 Yokozeki, H; Watanabe, K; Katayama, I; Nishioka, K. “gd T cells assist ab T cells in the adoptive transfer of contact hypersensitivity to para-phenylenediamine” Journal of Investigative Dermatology Volume: 108, Issue: 4, April, 1997. pp. 641. 

26 APIL “Lawyers Warn Women of Hair Dye Chemical Risks” http://www.apil.com August 2003

27 “Aromatic Amines: An Assessment of the Biological and Environmental Effects” Committee on Amines, Board on Toxicology and Environmental Health Hazards, Assembly of Life Sciences, National Research Council 1981 71

28 CDC “NIOSH Pocket Guide to Chemical Hazards” http://www.cdc.gov/niosh/npg/npgd0495.html http://www.cdc.gov/niosh/ipcsneng/neng0805.html 

29 EPA “Technology Transfer Network Air Toxics Website: p-Phenylenediamine” http://www.epa.gov/ttn/atw/hlthef/phenylen.html
 

Disclaimer!

I wrote this from my perspective, based on my own experiences and the references above. Any misquotations, misunderstandings or errors are mine and mine alone. 

I make no claims about what p-Phenylenediamine does or does not do, I am not an expert on the substance. 

I made my decision to stop using hair dyes with PPD based on my own anecdotal reactions to the stuff. I completely stopped using it after a couple of reactions. Also, the realization that the same PPD I harped against for henna body art was the stuff most likely to be causing my reactions. 

That said, PPD is not documented as unsafe or cancer causing, quite the contrary. That does not imply that it is safe or that it does not cause cancer, but studies found that it was safe enough for use and no clear links between it and cancer exist. 

Accordingly, the blame for henna and PPD mixes lies with the people who market products mixed against the recommendations of the companies who manufacture PPD.