On The Topic Of Hair Bleach

By Kelcie Brown 

Being a creative grooming organization, the NAPCG supports and encourages creatively grooming and coloring domestic pets… as long as the safety and the comfort of the animal are not sacrificed. While most creative coloring products are safe, there are a few that raise concern. Bleach, or a “hair lightener” product, is one such example, which is why the NAPCG does not support or condone the use of bleach on pets. Note that this refers to hair bleach, which is a peroxide bleach.1,2 This is not the same as a household cleaner, which typically contains a chlorine bleach (sodium hypochlorite being the most common).3 While household bleaches present health hazards all their own, this discussion and the references contained within pertain specifically to hair bleach.

This is understandably a controversial topic, as no one wishes to be accused to endangering their pet. However, although it has never been the intentions of the organization to condemn any specific person or group, we remain convicted in our stance against the use of bleach and will continue educating groomers and pet owners alike to the risks involved, risks that include exposure to harsh chemicals, such as hydrogen peroxide.

Hydrogen peroxide is the key ingredient in hair bleach formulas. It is the oxidizing agent that reacts with the hair to remove color1,2. Unfortunately, the reaction conditions required for destroying the naturally occurring chromophore are so extreme that side reactions occur simultaneously2. That is, bleach degrades structural proteins and can be particularly damaging since hair has a high protein content. 2 Jeong, et al4 states, “These hair treatments [bleaching] can lead to hair and skin damage which could result in a loss of the cuticle of the hair and the stratum corneum in the skin.” This means that, even when used “properly” (more on that later), bleach damages the hair it lightens and can damage the skin as well.2,4

Damaging the hair does not, arguably, physically hurt a dog, but I ask – What outcome could be so desirable that it is worth damaging the coat? Is it not the job of the groomer to care for the skin and the coat? That, of course, is a matter of ethics rather than safety. Regardless, inhalation of and contact with hydrogen peroxide pose many risks that ARE a matter of safety.

At the lowest concentrations found in hair bleach (3%), hydrogen peroxide can cause skin irritation via contact and respiratory irritation via inhalation5. Exposure to higher concentrations (>10%) may cause pulmonary irritation, blistering, and ulceration or perforation of the cornea5. Additionally, it can damage DNA structure and lead to cell death6. Lastly, and most importantly, the CSTEE specifically mentioned that dogs appear to be especially sensitive to the effects of hydrogen peroxide1, which is important for anyone who has used hair bleach themselves to consider. I know few people who do not notice the effects of bleach fumes; imagine the effect that must have on dogs, who are even more sensitive than we.

Next on the ingredient list are persulfates. Ammonium persulfate, potassium persulfate, and sodium persulfate are the most commonly used persulfate salts and are included in hair bleaching products to increase the reaction rate7-9. Persulfates are, arguably, even more hazardous than hydrogen peroxide, as they can induce a number of responses (both respiratory from inhalation and cutaneous from direct contact) including allergic eczematous contact dermatitis, localized edema, irritant contact dermatitis, localized contact urticarial, generalized uricarial, rhinitis, and asthma7-9. These symptoms have been reported as both immediate and delayed reactions to exposure to persulfate-containing hair bleach solutions8, meaning a dog may appear unharmed during a bleaching session but exhibit painful symptoms at a later time.

Furthermore, the NICNAS10 has concluded, “Over time, the airways and skin can become more sensitive to persulfates, so that less exposure is needed to produce a reaction. Once acquired, this sensitivity can be a life-time response,” and stated “Ammonium and Potassium Persulfate are classified as Hazardous Substances. The Report recommends that Sodium Persulfate be added to the list.”

Lastly on the topic of persulfates, De Vooght et al11 concluded that ammonium persulfate can initiate an asthmatic response in mice after a single airway exposure.

After reviewing this information, some may argue that bleach is not dangerous if applied correctly, but there is no “proper” way to apply bleach to a dog, as bleaching products were not created or intended for use on dogs.  Additionally, I present these cases of chemical burns that occurred at professional hair salons:

  • A 12 year-old girl experiences a “well circumscribed, erythematous ulceration with one purulent focus with an adjacent smaller similar ulceration” two weeks after a professional highlight treatment.12
  • A 13 year-old girl underwent a similar experience showing a “well circumscribed ulceration with prominent overlying granulation tissue and no visible hair within the ulceration“ five weeks after professional hair highlighting.12
  • After a 12 year-old girl underwent a professional bleaching session, “necrosis appeared on the scalp, leading to a sharply demarcated crust, which after a few weeks became detached together with the hair, leaving an oval-shaped ulcer measuring 9×9 cm. Plastic surgery with excision of the ulcer base and placing of a skin graft was performed.”13
  • A 16 year-old female underwent her routine highlighting procedure at her local hair salon. Two weeks later, “she was noted to have two well-demarcated, circular full-thickness burns with central ulceration at the top of her scalp.”14
  • Hoekstra et al8 lists 8 case studies involving reactions to persulfates from salon-related incidents, as well as 24 case studies documenting occupational injuries caused by exposure to persulfates.

Keene15 makes mention that the number of complaints concerning hair dyes reported to the Food and Drug Administration suggests that these types of burns occur more commonly than what is recorded and notes that cases such as those listed above are almost certainly chemical in nature, rather than thermal, meaning the ingredients contained within the bleaching solution are to blame rather than overheating during application.

Professional hair stylists have been thoroughly trained to properly apply bleach, and yet, as mentioned, these cases are surprisingly common. Despite this, bleach remains prevalent in the human hair industry because we are capable of understanding the risks involved and of making a conscious choice to have our hair colored however we desire. Dogs cannot choose to be exposed to these risks, nor do they benefit from being bleached.

It is important to maintain perspective in this situation. Some say topical flea products are dangerous, and therefore, we should not condone their use. Flea products do, indeed, present health hazards, but those hazards are considered by most to be less severe than the flea infestations they prevent. In that case, the preventative care is greater than the risks incurred. There is absolutely no outcome of bleaching that is medically beneficial to an animal.

A few groomers choose to disagree with the organization’s stance against bleach on the grounds that dogs have been bleached in the past with no ill effects, offering this as evidence in favor of bleaching. However, the lack of recorded cases of hair bleach injuring dogs does not necessarily indicate its safety, as bleach is not a common practice in either the show world or the grooming world. Additionally, imagine the negative responses a groomer would receive from both those who support bleach and those who are against it were they to openly admit to harming their dog during a purely cosmetic procedure. Therefore, it is understandable, although not condonable, for a groomer to conceal it, especially in the show world, where bleaching is explicitly against the rules.

Let us not forget, too, that it is possible for ill effects to occur that are not necessarily noticeable, such as general airway discomfort or the development of asthma. Additionally, as mentioned earlier, persulfates are sensitizing, meaning a reaction could occur where there had been none in the past. Therefore, a dog is just as at risk of reaction whether it is the first time it has been bleached or the hundredth time it has been bleached. In fact, repeated exposure to hair bleach is a major concern for hairdressers and has lead to many chronic health complications8, 11, which shows that problems may arise, even if an initial reaction does not occur.  

Even if there are dogs that have not suffered and will never suffer any adverse reaction to bleach, the available research indicates that there is a significant risk for harm. This does not mean that it always results in injury, simply that the chances of injury are too high for its use to be justified. This is important because there is a small risk for a dog to have an allergic reaction to any grooming-related product, but it is not such a significant risk nor is the risk so severe as to warrant the ban of those products. If you have reviewed the literature but still ask where the line is drawn between a significantly dangerous product and one that has a very slight chance of causing a reaction, then consider how many grooming products contain such lengthy warning and safety advisory labels as bleach.  Consider, too, how many other products we apply to a dog’s coat that require us to wear gloves to prevent chemical burns on our hands.

The last argument I wish to address is that of the unnatural color removers – those who bleach not to remove natural color pigmentation but to remove dye or stains. I have heard some insist that the lower concentrations (~3%) used are less harmful, and this is true, but that does not mean that lowering the concentration removes all risk of harm, especially when considering that bleaching tearstains, in particular, exposes the most vulnerable part of a dog’s body to persulfates and hydrogen peroxide. The fumes are near its airways; its eyes are awfully close to the mixture; and the bleach is applied extraordinarily close to the skin, including the very delicate tear ducts.  There are enzyme-based solutions that may require more regular usage than bleach but do not compromise the dog’s safety, so why expose a dog’s face to these products when other, safer alternatives exist?

In conclusion, the information provided from the listed references and the accompanying discussion of this information irrefutably demonstrate the significant dangers of using hair bleach. It is the opinion of the NAPCG that the potential for injury caused by bleach is such to warrant the ban of its use from creative grooming competitions and that it should not be used on a pet for any purpose. However, if anyone chooses to disagree with this information, perhaps they at least understand why the organization has taken the stance it has.

For my final words in this discussion, I would like for my readers to consider – When dogs cannot choose to be exposed to the dangers of bleaching and they do not benefit from the outcome, what purpose could there be for bleaching a dog that does not arise from a human’s selfish desires, especially when safer alternatives exist?

Note: Please keep questions or inquiries professional and remain patient while awaiting a response.



  1. Scientific Committee on Toxicity, Ecotoxicity, and the Environment (CSTEE) Opinion on the results of the Risk Assessment of: HYDROGEN PEROXIDE, HUMAN HEALTH EFFECTS, CAS No.: 7722-84-1, EINECS No.: 231-765-0
  2. Robbins, Clarence. Chemical and Physical Behavior of Human Hair. Fourth Edition. New York: Springer-Verlag New York, Inc, 2002.
  3. Rutala, W, and D Weber. “Uses of Inorganic Hypochlorite (Bleach) in Health-Care Facilities.” Clinical Microbiology Reviews. 10.4 (1997): 597-610.
  4. Jeong, M, C Lee, W Jeong, S Kim, and K Lee. “Significant damage of the skin and hair following hair bleaching.” Journal of Dermatology. 37. (2010): 882-887.
  5. Agency for Toxic Substances and Disease Registry (ATSDR), Hydrogen Peroxide, CAS: 7722-84-1
  6. “Hydrogen Peroxide.” International Agency for Research on Cancer (IARC) – Summaries & Evaluations. 71. (1990): 671.
  7. Fisher, A, and A Rooms-Goossens. “Persulfate Hair Bleach Reactions: Cutaneous and Respiratory Manifestations.” Arch Dermatol. 112. (1976): 1407-1409.
  8. Hoekstra, M, S Heide, P Coenraads, and M Schuttelaar. “Anaphylaxis and Severe Systemic Reactions Caused by Skin Contact with Persulfates in Hair-Bleaching Products.” Contact Dermatitis. 66. (2011): 317-322.
  9. “Final Report on the Safety Assessment of Ammonium, Potassium, and Sodium Persulfate.” International Journal of Toxicology. 20.3 (2001): 7-21.
  10. Australia. National Industrial Chemicals Notification and Assessment Scheme. Safety Info Sheet No. 18. 2001. <http://www.nicnas.gov.au/Publications/Information_Sheets/Safety_Information_Sheets/SIS_18_Ammonium_Potassium_And_Sodium_Persulfate_PDF.pdf>.
  11. De Vooght, V, M Cruz, et al. “Ammonium Persulfate Can Initiate an Asthmatic Response in Mice.” Thorax. 65 (2010): 252-257.
  12. Lund, J, R Unwala, L Xia, and V Gottleib. “Chemical Scalp Burns Secondary to the Hair Highlighting Process: Clinical and Histopathologic Features.”Pediatric Dermatology. 27.1 (2010): 74-78.
  13. Jensen, CD, Sosted H., “Chemical Burns To The Scalp From Hair Bleach And Dye.” Acta Derm Venereol 86 (2006): 461–462.
  14. Maguina, P, M Shah-Khan, G An, and M Hanumadass. “Chemical Scalp Burns After Hair Highlights.”Journal of Burn Care and Research. 28 (2007): 361-363.
  15. Keene, Sharon. “Scalp Necrosis and Scarring Alopecia Caused by Chemical Burns from Hair Highlighting Procedures.” Hair Transplant International Forum. 21.2 (2011): 44-47. Web. 1 Jul. 2012. <http://www.ishrs.org/members/forum-pdf/F2-2011.pdf>.


Additional resources:

  • http://www.hairfoundation.org/blog/hair-lightening-and-skin-damage/
  • Valks R, Conde-Salazar L, Malfeito J, et al. “Contact dermatitis in hairdressers, 10 years later: patch-test results in 300 hairdressers (1994 to 2003) and comparison with previous study.” Dermatitis 16 (2005): 28-31.
  • Munoz X, Cruz MJ, Orriols R, et al. “Occupational asthma due to persulfate salts: diagnosis and follow-up.” Chest 123 (2003): 2124-9.
  • Blainey AD, Ollier S, Cundell D, et al. “Occupational asthma in a hairdressing salon.” Thorax 41 (1986): 42-50.
  • Moscato G, Pignatti P, Yacoub MR, et al. “Occupational asthma and occupational rhinitis in hairdressers.” Chest 128 (2005): 3590-8.
  • Pepys J, Hutchcroft BJ, Breslin AB. “Asthma due to inhaled chemical agents: persulphate salts and henna in hairdressers.” Clin Allergy 6 (1976): 399-404.
  • Parra FM, Igea JM, Quirce S, et al. “Occupational asthma in a hairdresser caused by persulphate salts.” Allergy 47 (1992): 656-60.
  • Cruz MJ, De Vooght V, Munoz X, et al. “Assessment of the sensitization potential of persulfate salts used for bleaching hair.” Contact Dermatitis 60 (2009): 85-90.








  1. Way to go Kelcie! I know this took a long time to get together and you did an amazing job!

    • Thanks Ashley!

  2. I was cleaning my dogs hot spot with hydrogen peroxide at 5 in the morning, and didn’t realize i had spilled a large amount on her fur until 2 hours later. It was still wet. 2 days later her fur in that area has been falling out but the hotspot is gone and she is not itching. Do you think the hydrogen peroxide could have caused this?

  3. Awesome job! I shared this info with my clients so that THEY can be well informed on this subject! :D Thank you for all your hard work!


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