Parabens — A common allergen with lots of hype and no real harm
By Christen M. Mowad, MD
Sept. 4, 2019
Vol. 1, No. 26
Every year for the past 20 years, the American Contact Dermatitis Society (ACDS) has highlighted an allergen. Most often the particular allergen is selected because it is new and emerging, such as methylisothiazolinone in 2013. (1) Sometimes, it is because the allergen is well- known, but now has new exposure routes. Such was the case with nickel, the allergen of the year for 2008 because of exposure to both biomedical devices and cell phones. (2) Paraphenylenediamine, allergen of the year for 2006, was chosen because of new exposures via temporary tattoos. (3) Occasionally the ACDS highlights allergens because they are the subject of much discussion but are not believed to be significant — such was the case with thimerosal, the contact allergen of the year in 2002 and now with parabens, the contact allergen of the year for 2019. (4,5)
Parabens are very common preservatives that have been used in personal care products, food, and pharmaceuticals for decades. Recent data from the ACDS Contact Allergen Management Program (CAMP) revealed that 19% of all products contained parabens. (5) They have little allergenicity, especially when compared to other preservatives. Reactions to parabens are rare. The use of parabens has become commonplace because of their low toxicity, safety profile, and cost. The most commonly used parabens are methylparaben, ethylparaben, propylparaben, and butylparaben. They can be utilized either alone or in combination. (5)
Over the years there have been many concerns regarding paraben safety and adverse effects from paraben exposure. Some of these apprehensions include endocrine problems (estrogenic effects), cancer concerns (breast cancer via xenoestrogen-oncogenicity connection), fertility issues (decreased sperm counts), prenatal exposures (physical growth, sperm count, ovary weights, adipogenesis), mood (higher need of emotional support) and environmental issues. (6,7,8) There is much debate in the literature and the public regarding these concerns but the existing research does not suggest any confirmatory adverse effects associated with exposure to parabens. (6,7,8) Despite safety concerns from the public, parabens have been classified and generally regarded as safe. (8)
In addition to cutaneous exposure, we are also exposed to parabens systemically through foods, both natural and processed, as well as oral medications. (7) Parabens have a short half-life and are rapidly metabolized and excreted in the urine. (6) Systemic contact dermatitis from ingestion of parabens is very rare. Therefore, patients with paraben allergy should be instructed on how to avoid them topically but the need to avoid them in foods and oral medicines is not routinely indicated. (7)
Despite public concerns and the widespread use of parabens, the allergen rate is low. When patch tested, a paraben mix is typically used to screen for contact allergy, combining 4 or 5 individual parabens at varying concentrations. The North American Contact Dermatitis group reports allergenicity ranging from 0.5- 3.7% but most recently has been reported at 0.6%. (5) This is significantly lower than other preservative allergens typically tested for such as methylisothiazolinone which was most recently reported at 13.4% or quaternium 15 at 3.6%. (5) Notably, the voluntary cosmetic registry reported over 44,000 products using parabens and only 231 using quaternium-15. (9) Although only a voluntary report, this demonstrates the confidence industry has in paraben safety.
Despite public safety concerns, parabens have been used extensively for decades due to low toxicity, reduced cost, and chemical inertness. Studies have shown them to have low allergenicity rates, especially when compared to other preservatives, and there is no evidence-based data in the literature to support any safety concerns. This allergen of the year is widely used and has a lot of hype but no harm.
Point to remember: Parabens are widely used preservatives found in many over the counter products and foodstuffs, yet they have been found to have little allergenicity, toxicity, or safety concerns. Despite public concerns, there is no significant harm related to these allergens.
Our editor’s viewpoint
Warren R. Heymann, MD
Admittedly, contact dermatitis is not my area of expertise. I decided to do what everybody else does to learn more about a topic — I Googled “parabens safety and danger” and instantly had access to 172,000 results (no, I did not read them all!). Results ranged from “they are safe” to virtual conspiracy theories about their harm (mostly hormonal). In fairness, one gets the sense that safety reigns supreme. Quoting Reeder and Atwater (reference 7): “Although there have been consumer concerns regarding endocrine disruption or carcinogenicity associated with parabens, definite evidence of their harm is lacking in the scientific literature, and many studies confirm their safety. With their high prevalence in personal care products and low rates of associated contact allergy, parabens remain ideal preservative agents.” The ACDS is to be congratulated on choosing parabens as the “nonallergen” of the year. Sometimes you can get to the top for what you’re not.
1. Castenedo- Tardana MP, Zug KA. Methylisothiazolinone. Dermatitis Jan-Feb;24(1):2-6, 2013.
2. Kornik R, Zug KA. Nickel. Dermatitis 19(1): 3-8, 2008.
3. Deleo V. Contact allergen of the year: Paraphenylendiamine. Dermatitis 17(2):53-55, 2006.
4. Belsito DV. Thimerosal: Contact Nonallergen of the Year. Dermatitis 13(1): 1-2, 2002.
5. Fransway AF, Fransway PJ, Belsito DV et al. Parabens. Dermatitis 30(1):3-31, 2019.
6. Fransway AF, Fransway BS, BElstio DV et al. Paraben Toxicology. Dermatitis 30(1):32-45, 2019.
7. Reeder M, Atwater AR, Parabens: The 2019 Nonallergen of the Year. Cutis 103(4):192-193.
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