Neograft | 703-844-0184 | Alexandria, Va 22306 | Hair Restoration | FUE | Hair Loss treatment | Fairfax, Va 22306 | Hair Dyes and allergies – PPD | Hair Care | Hair Loss Center


703-844-0184 | Hair restoration | Neograft Hair Transplantation | FUE | Hair loss Doctor | Alexandria, Va 22306  Call for appointment


Hair dyes not only color the hair but sometimes color the hair follicle openings or “pores”. This causes the hair follicle openings to appear as brown globules. Not all hairs effectively take up pigment – a few grey non-dyed hairs can be seen in this photo.


hair dye

Hair Dye Colors the Openings of Hair Follicles

Hair dye can sometimes alter the up close appearance of the scalp. Hair dyes can deposit on the scalp given the appearance of hyperpigmentation. In addition, the hair follicle openings or “pores” can take up pigment simulating the appearance of “dots.”

Hair dye is generally safe for most patients with hair loss. However one must be aware that freshly dyed hair may take on a slightly altered appearance. This photos shows brown dots coating hair follicles in a patient with frontal fibrosing alopecia (FFA).


hair dye



Hydrogen peroxide inhibits hair growth in lab models


This has been a question that has been discussed for some time. I have become increasingly interested in this topic as it is clear to me that at least for a small proportion of patients – hair salon visits can negatively affect their hair. Many people of course are fine and unaffected by hair dye. For others, however, the process of dyeing and bleaching can cause significant problems, including hair loss.

There are many potential reasons why someone using hair dye can raise concerns about hair loss that is potentially related to the dye. It is clear that the use of hydrogen peroxide in many dyes can induce “oxidative stress.” This oxidative stress is toxic to cells.

A New Study Examines the Effect of H202 on Hair

Researchers from Korea set out to examine the effect of hydrogen peroxide on growing hair follicles in a laboratory setting. The researchers isolated hairs from a patient and grew them in a petrie dish. Then hydrogen peroxide at various concentrations was added. Results showed that H2O2 inhibited growth of hair follicles in a concentration dependent manner and did so by inhibiting a pathway inside cells known as the GSK3- beta pathway.

The evidence is accumulating that hydrogen peroxide has a growth inhibitory effect in vitro (in cultured and controlled conditions in a laboratory). More studies are needed to understand if and how hydrogen peroxide actually affects growing hair follicles deep under the scalp and whether the thick and someone resilient skin layer actually allows hydrogen peroxide to get under the skin to affect dermal papillae or “DP.” For now, if a patient truly feels that hair dye is affecting the hair, I advise searching for alternate means to color hair which avoids hydrogen peroxide. For many patients however, hair dye use continues to be unproblematic.


Colouring Hair When Hair Dyes are a Problem

In general, temporary type dyes are safer/better tolerated than semi-permanent and semi-permanent are better tolerated than permanent. The richness of the colors and how pleased patients are seems to go in the opposite order: permanent dyes create some of the nicest color effects.  There are a number of dyes which are PPD free and free of ammonia, parabens, silicone, formaldehyde. There are several companies. For patients with a lot of issues, henna can be considered. Also, I find that many patients improve their tolerance with pre-shampooing with clobetasol propionate based shampoos (i.e. Clobex shampoo) the day before (or morning before). In general though, I have a pretty low threshold for recommending a patch test to rule out allergy in patients with problems to hair dyes.


Ohn et al. Hydrogen peroxide suppresses hair growth through down regulation of beta catenin. Journal of Dermatological Science 2018.

Hydrogen peroxide (H2O2) suppresses hair growth

Hydrogen peroxide inhibits pigment synthesis


Hydrogen peroxide (also known as “H2O2”) is a well known bleaching agent and disinfectant. It is a household item for many people.

Hydrogen peroxide is also found in hair – and in fact accumulates in white and gray hair. It inhibits the synthesis of pigment known as melanin.



Schallreuter KU, et al. The redox–biochemistry of human hair pigmentation.  Pigment Cell Melanoma Res. 2011

The redox – biochemistry of human hair pigmentation


Chemical injury can lead to scarring alopecia

hair highlights.png

Hair dyes, highlights and bleaching can rarely lead to chemical injury. It’s not common of course but the story is always the same: within seconds to minutes of applying a hair dye or highlights, the patient complains of intense burning and/or pain and requests the product to be removed. Hours to days later hair loss starts and within a week or two the patient has permanent hair loss (such as shown in the figure to the right). I have seen this type of scalp injury phenomenon many, many times and I do even feel that it is increasing world-wide.


Management Chemical Injury to the Scalp

The most important thing to do in these situations of potential chemical irritation is remove whatever chemical could be causing the reaction. The dye or highlight must be removed, neutralized and rinsed off.  In my opinion a dermatologist should be consulted for management and monitoring. Rarely skin necrosis can occur from ehuberant reactions. One can not predict on day 1 whether the patient will have hair loss and whether any hair loss will be permanent. This will not be clear until day 14-28. In the short term one must management skin health, prevent infection, and limit and control inflammation. These are within the skills of a dermatologist.  A biopsy may be considered to determined the type of inflammation and evaluate for scarring if it is unclear.


Hair transplantation or Surgical Correction: Best methods for Camouflaging Chemical Injury

Too often I hear it said in these scarring alopecias that a biopsy was done and because the biopsy said the disease was inactive the patient proceeded to surgery. Keep in mind that we determine if a scarring alopecia is inactive by simply following what it does over time. Relying on a biopsy alone to determine if it is acitve is not a good idea for most people. If the area of hair loss has not changed at all in any way shape or form (same size area) and is not itchy and has no burning or pain thena biopsy supports it is inactive.  Even if a biopsy says the scarring alopecia is inactive but the area is expanding over time and is itchy or red… it is not inactive. This is a common scenario and a common error in managing scarring alopecia.

One needs to wait 12-24 months for a scarring alopecia before surgery. Photos need to be done every 2-3 months in my opinion even for chemical burn related hair loss. If the photos look the same when placed side by side over a one year period, one can say the scarring alopecia is probably quiet.  Rarely, this can be shortened to 6 months for chemical injury but one year is a safer waiting period to be confident there is no evidence of a slowly progressive scarring alopecia in evolution.


Is waiting really necessary when planning surgery in scarring alopecia?

All this background waiting and monitoring needs to be done before surgery. It sounds excessive and time consuming and unnecessary- but it is far from it. Surgery for scarring alopecia can be highly successful provided it’s done in the right patient. Too often, it is not done on the right patient… and then it does not work well or does not work at all and physicians, patients and the medical community as a whole loses confidence in the value of surgical restoration options.


Options for Restoration

The only way to restore the appearance is surgical. Medical options do not help improve density once the area is permanently scarred. If the area is small surgery via a plastic surgeon can be a great option. Many burns from hair dyes are in the form of small coin shaped patches. A flap (rotational flap etc) can work wonders and may be superior to hair transplanting. For this a surgeon is needed with skill in such flaps. The above patient would be a good candidate for a flap.

For hair loss that occurs more diffusely (and not in the above mentioned classic hair dye chemical burn patches), hair transplants can sometimes ca a good option. In my opinion, the key factor in choosing a surgeon is their experience and dedication to hair transplantation. The actual credentials is not so important to me and some of the world’s top surgeons are a range of family physicians, dermatologists, plastic surgeons, former emergency room physicians. If her or she is dedicated solely to hair transplanting and has performed a large number surgeries and has been doing it for many years and has a good before and after album of scar procedures, then it may be worth a visit to speak to that surgeon.



PPD allergy and “Cross Reactions”

Paraphenylenediamine (“PPD”) is the major allergen contained in hair dye. Allergy to PPD is increasing around the world and many are dyeing their hair at younger and younger ages. Individuals who are allergic to their hair dye may develop scalp swelling and blistering. However, many do not and only develop reash on the eyelids, ears, neck, forehead or face.  Reactions to PPD can be serious and life threatening and one must take these issues very seriously to avoid progression from a mild hair dye allergy to a severe life threatening reaction. Patch testing is a type of testing that can identify potential allergens  that a person is reacting to.

Allergy to PPD means one must educate themselves …. and others!

Individuals who an allergy to PPD also frequently react to other compounds as well. These include parabens, black rubber mix, sunscreens (ie PABA sunscreens), various dyes (especially yellow and ornage azo dyes and analine), benzocaine/procaine anesthetics. Many patients with PPD allergy react to henna tattoos because these also contain some amount of PPD. In addition, there are certain medications that patients with PPD allergy best avoid. Individuals with PPD allergy may develop severe generalized reactions followed use of thiazide diuretics (hydrochlorothiazide), sulfonylureas (diabetes medications), celocoxib, and sulfonamide antibiotics.



There have been recent reports in the news of women having serious reactions to a specific ingredient found in some hair dyes.  The ingredient is paraphenylenediamine or “PPD” for short.  Many patients have asked me about these articles appearing in various newspapers reports.

PPD is commonly found in permanent and semi-permanent hair dyes. It is used to help give a hair dye a dark color that doesn’t easily wash out.  PPD also gives hair dyes a natural, realistic color.

Despite making the news recently, there is nothing new about allergic reactions to PPD.  It is well known that PPD can cause some sort of allergic reactions in about 5% of users. These allergic reactions vary from skin rashes & blisters (a phenomenon called allergic contact dermatitis)  to hives (a phenomenon called contact urticaria) to serious anaphylactic reactions and rarely even death.  Reactions can occur as a few days to a week or more after application of a hair dye.  These reactions tend to occur on the second, third or fourth application rather than on the very first.

Health Canada has banned the use of PPD in cosmetic products that are applied directly to the skin.  For example, PPD is banned in black henna tattoos which are sometimes known as holiday tattoos because vacationers may have these dark richly pigmented tattoos applied while enjoying a vacation.  However, PPD is not banned in hair dyes.  PPD is allowed in hair dyes provided the product labelling contains a warning about possible allergic reactions. On its website, Health Canada states

PPD is an acceptable ingredient for use in hair dyes that are rinsed off after a maximum of 30 minutes. When used correctly, hair dye does not come directly into contact with skin for prolonged periods of time.

Allergic reactions to PPD include red skin rashes, itching, blisters, open sores, and scarring within 2 to 10 days following application. These allergic reactions may also lead to sensitivities to other products such as hair dye, sun block and some types of clothing dyes.


My general advice for individuals considering dyeing their hair:

1) Read the instructions on the package carefully.  If there are no instructions, don’t buy the product.

2) Be sure to do a “patch test”. Apply a small amount (size of a penny) to an area on the skin. An area such as behind the ear or on the forearm is a particularly good spot.

3) Let it dry.

4) If immediate redness develops, the individual may be ‘irritated’ by the product. This usually does not indicate an allergy.

5) Wait 72 hours (3 days) and do another check of the area where the dye was applied.

6) If there is no reaction, then the test is said to be “negative”. Individuals who have a “negative” test are unlikely to develop an allergic reaction when they use a hair dye.

7) If the individual develops redness, scaling and/or blisters in the area where the patch test was applied, they may be truly allergic to the PPD chemical.  Use of the hair dye is not recommended. Take a picture of the reaction. Make an appointment with a physician knowledgeable about hair dye allergy to discuss further.

8) In general, semi-permanent dyes have less PPD than permanent dyes, so try to use them first to see if you can achieve your desired color.  To even further reduce your exposure to PPD, try to use  the lightest color possible. Highlights or low lights can be used too because these don’t touch the scalp. Consider experimenting with natural colors, which don’t contain PPD


Many individuals ask if they could be allergic to their hair dye.   The answer is more likely to be “no” than “yes”, but it is possible to be allergic to hair dyes.    In North America, over 60 million consumers color their hair.  Allergic reactions to hair products are probably under reported so we don’t know the exact prevalance.

There are four main types of hair dyes on the market: gradual, temporary, semi-permanent and permanent. The most popular types of hair dyes are the permanent dyes and the permanent dyes are the most likely types of hair coloring products to cause allergy. Individuals who are allergic to hair dyes sometimes develop a rash on the neck, forehead, eyelids, ears or even the hands.   The scalp may be red, crusted and oozing fluid.   Individuals with severe hair dye allergies may also feel unwell.

The main culprit in permanent dyes to cause allergic reactions is a chemical called para-phenylenediamine, or “PPD” for short. Other chemicals in hair dyes may also cause allergic reactions.  Specialized allergy testing called patch testing, can sometimes be used to confirm if an individual is allergic to their hair dye.



Premature graying

By age 50 about 50 % of the population has a good amount of grey hair. But what about those who develop grey hair in the 20s and 30s?

The term “premature graying” refers to graying of hair that happens before the age of 25 in Caucasians and before age 30 in black men and women. From time to time, I evaluate patients in my hair loss clinic who start graying in the teens or twenties.


What are the causes?

Many, many factors influence hair graying – especially genetics. Some individuals simply have the genetic predisposition to develop grey hair. Other causes also need to be considered including thyroid abnormalities, pituitary problems, and deficiency of vitamin B 12.

Smoking too can cause early graying of hair. In fact, 20 years ago, a study in the British Medical Journal showed that smokers are about two to four times more likely to have grey hair. A recent study supports a possible link between low iron, calcium and vitamin D but that needs to be further investigated.

Autoimmune conditions like alopecia areata, vitiligo as well as premature aging syndromes (like a condition called Werner’s) can cause affected individuals to develop early graying.



Overall, early graying of hair is fairly common and not usually associated with any underlying problem. That said, a full workup is needed for graying that fits the definition of premature graying.


Leave a Reply

Your email address will not be published. Required fields are marked *