2. Materials and Methods
Search tool and strategy
Study design: A retrospective bibliometric analysis was used.
Inclusion criteria: All the documents published between 1957 and April 2021 were included in the study. All the manuscripts were considered in this study including letters to the editor and note.
Exclusion criteria: Manuscript published after April 2021 were excluded from the study.
To acquire articles on the adverse effects of cosmetics across time, the Scopus database (
https://www.scopus.com, 24 April 2021, Elsevier, Amsterdam, The Netherlands) was used. “Scopus
® is the world’s largest abstract and citation database for peer-reviewed literature, with the most comprehensive analysis of published papers in the field of health science” [
9]. The descriptive bibliometric analysis was carried out using Scopus’s built-in functions. (“Distribution of types of documents and the most prolific publications, authors, institutions, and countries”). In March 2021, the search was performed using the keywords “cosmetics” and “adverse effects” as a search term to retrieve all possible papers aggregated within the group from the Scopus
® database. For the trend analysis of the average number of articles, pages, references, organizations, authors and citations each year, we exported all information with reference records (all article editors and references) from the Scopus database in CSV format into Microsoft Excel (Redmond, WA, USA), and used Excel’s Generate Text feature and its statistical functions to determine yearly averages. We also produced bibliometric network maps that depicted the most commonly used keywords, as well as the relationships and connections between countries. In this research, we used the freeware resource VOSviewer (Centre for Science and Technology Studies, Leiden University, Leiden, The Netherlands) to create bibliometric network visualization maps. The role of the software is connecting the nodes in the network to the clusters; thus, in a way, a cluster is a set of nodes that are loosely related. As the value of this parameter grows, the number of clusters also increases. Each cluster is represented accordingly by a color. The terms that are more important have larger circles, and terms that were strongly related to each other were closer. Lines between terms indicate, by thickness, a stronger link between the two terms [
10,
11].
4. Discussion
The global cosmetic industry is estimated to be worth about
$20 billion dollars today [
12]. The cosmetic industry has seen tremendous growth in the last 20 years, resulting in a wide variety of products to protect and moisturise skin, as well as fight inflammation and signs of ageing [
13]. The cosmetics industry is a highly creative industry and contributes significantly to national and regional economies around the world [
14]. Innovation is one of the basic principles in this field. Women, in particular, use beauty products that may contain harmful cosmetic ingredients [
12].
“Cosmetics are preparations that are applied directly to the human skin, hair, and nails, however, recent concerns about their safety have been increasing”. Metals in cosmetics may be retained and absorbed into the bloodstream, causing harmful effects in various organs [
15]. Preservatives, stabilisers and mineral pigments are applied to cosmetic products to improve their consistency and quality. In order to obtain a better shine in some mineral pigments, glitter and dye are added to these products. Any of these substances can cause allergic reactions, irritation and harm to human health [
5]. Acute toxicity, skin irritation, eye irritation, skin sensitization, sub-acute toxicity, mutagenicity/genotoxicity, type IV hypersensitivity, contact urticaria and other adverse effects can occur due to the use of cosmetics [
16]. Irritant contact dermatitis is the most prevalent problem associated with the use of cosmetics. [
17]. Perfumes, nail polish and other skincare items stay on the skin for longer periods of time and might cause allergic reactions [
18]. “Skin care products are [sic] a kind of umbrella term covering cleansing, changing appearance, perfuming, changing body odor, protecting and keeping the skin in good condition” [
19]. “Perfume is a mixture of fragrant essential oils or aroma compounds, fixatives and solvents, used to give the human body, animals, food, objects, and living-spaces an agreeable scent.” [
20]. “A fragrance consists of volatile chemicals with a molecular weight of less than 300 Da that humans perceive through the olfactory system” [
21].
Some of the common cosmetics products and their toxicities are:
Shampoos: Hydrogen peroxide solutions and ammonium persulfate, which are active chemicals in hair bleaching products, can trigger Types I and IV allergic contact reactions [
12].
Skin lightening agent: Hydroquinone (HQ), a skin lightening agent, has been identified as one of the most dangerous substances. Reports of ochronosis and possible mutagenicity have been discovered. Ochronosis is a rare HQ side effect, characterised by a gradual darkening of the area to which a cream containing high concentrations of HQ has been applied for many years. It causes irritation, burning and redness of the skin [
22].
Henna dye, hair dye: Henna dye and hair dye contains the ingredient PPD (p-phenylenediamine) which can cause allergic reactions including blisters, surface oozing, weepy dermatitis, eczematous dermatitis, pruritic dermatitis, swelling and erythematous rashes on the skin [
23].
Deodorants or antiperspirants: Ingredients or fragrances which are present in deodorants or antiperspirants may cause allergic reactions. Fragrances enter the body, through the nose, directly into the brain and can cause headaches, fatigue, dizziness and irritation to eyes, nose and throat. When fragrances are found in the air, they can cause airborne contact dermatitis. Phthalates present in fragrances are suspected hormone disrupters. Fragrances which are present in perfumes can cause allergic reactions, headaches and asthma [
24].
The adverse effects associated with ingredients used in the formulation of cosmetics:
BHA and BHT: In moisturizers and lipsticks, synthetic chemicals such as BHA (butylated hydroxyl anisole) and BHT (butylated hydroxyl toluene) can cause allergic reactions to the skin. The International Agency for Research on Cancer has classified BHA as a human carcinogen. BHT in high concentrations can imitate hormones like oestrogen, and block the development of male sex hormones, causing reproductive problems [
12,
25]. When applied in high concentrations, moisturisers can irritate and exfoliate the skin [
18].
Parabens: Preservatives are used to protect cosmetics from microbial contamination. The most commonly used preservative are parabens, which penetrate the skin and are suspected to interfere with hormonal functions. They imitate hormones like oestrogen and interfere with male reproductive function. When methylparaben is applied to the skin, it combines with other chemicals present in cosmetics, causing skin aging [
12,
26].
Siloxanes: Siloxanes are silicone-based chemicals that are used to soften and smooth a variety of cosmetic products. They are commonly used in facial treatments and moisturizers. Cyclotetrasiloxane and cyclopentasiloxane are two extensively used siloxanes that are hazardous to human health. Cyclotetrasiloxane is classified as an endocrine disruptor that interacts with human hormone function and, as a potential reproductive toxicant, may damage human fertility [
12,
27].
Adverse effects associated with heavy metals in cosmetics:
Heavy metals: Heavy metals present in cosmetics can accumulate in the body over a long period and can cause contact dermatitis, cancer, vomiting, reproductive disorders and headaches.
Lead: Lead is a heavy metal that can be found as an impurity in lipsticks and eye powders such as kajal, and has been associated with high blood lead levels in women and children, which are toxic to the body. Pregnant women are at higher risk because it can easily cross the placenta and reach the foetus’ brain. It can also be transferred to infants through lactating mothers’ milk [
12,
28].
Cadmium: Cadmium is a heavy metal that is present in most body and hair creams; it is absorbed into the body through dermal contact and stored in the kidney and liver. If ingested in high amounts it may lead to vomiting and severe stomach irritations. Exposure over a long time may lead to kidney damage [
12].
Mercury: Mercury is a major ingredient used in most creams, skin lightening soaps and eye makeup. It is found in cosmetics in organic and inorganic forms. Kidneys are the major site of deposition of inorganic mercury; kidney damage is a common side effect of the inorganic mercury found in lotions and skin whitening soaps. Inorganic mercury poisoning has been reported in the USA, Mexico, Africa and Europe [
29]. Because of health concerns, the US FDA has restricted nine ingredients from cosmetics, while the EU has banned over 1000 ingredients. The use of cosmetics should be limited, and people should be informed about the composition and application of cosmetics to reduce their harm [
30]. To promote changes in the manufacture, marketing and use of cosmetic products by the general population, it is critical to apply a standard cosmetovigilance over the world [
12,
31]. “Cosmetovigilance is a model of safety monitoring of cosmetics. It can be considered as one of the elements in public health activities” [
32]. This public health policy is a legal way of gathering information on the safety of cosmetics and their ingredients, in order to reduce the risks associated with cosmetics use [
12,
31].
Cosmetovigilance systems, in different countries, are as followed:
Europe: Cosmetics products sold in the European Union (EU) should meet stringent safety and quality requirements. The Cosmetics Regulation (EC) No. 1223/2009 of the European Union (EU) requires companies to collect and analyse reports of adverse health consequences (undesirable effects) from the cosmetic products they market [
33,
34].
Netherlands: The Netherlands Food and Consumer Product Safety Authority and the Netherlands Ministry of Health have agreed to monitor the adverse effects of cosmetics and have expressed a willingness to cooperate toward the establishment of a cosmetovigilance network [
34].
Canada: In Canada, healthcare professionals and consumers are encouraged to report side effects as per their Natural Health Products (NHP) Regulations, which started in January 2004. The NHP is in charge of ensuring that all cosmetic products are properly licenced, sufficient evidence for safety and efficacy is provided, appropriate labelling is provided, good manufacturing practises are followed, ADRs are reported, clinical trials related to cosmetic products are kept up to date and be the source of information for product recalls to all consumers. There are reporting forms, with which adverse events must be reported within 15 days [
35].
USA: In the USA cosmetics labelling and purity have been made necessary for the marketing of cosmetics by the US Food and Drug Administration. As a result, it is the responsibility of the cosmetics manufacturer in the United States to provide high-quality cosmetic products [
36].
Germany and Sweden: These are the two countries that have a formal cosmetovigilance system. In Germany, information on human health effects after exposure to any kind of substance, including cosmetics, is submitted to the BfR (Budensinstitut fur Risikobewertun) in Berlin. Sweden has a Cosmetovigilance Center, which was established in 1989. The Department of Cosmetics, which is part of the MPA (Medical Products Agency) located in Uppsala, is in charge of it. It represents the Swedish national authority, which is responsible for collecting ACRs reported by various professional categories/persons (mostly general practitioners and medical specialists) [
37].
India: Due to a lack of a well-organized reporting system in India, undesirable reactions to cosmetic products go unreported. Cosmetic-related adverse reactions have so far remained undetected. It is time for India to establish a formal cosmetovigilance system [
38].
Most of the authors and organisations on the top ten productive lists were from developed countries, according to our findings. We found that Harvard Medical School was first among the top ten institutions reporting research investigating adverse cosmetics effects (1.16) (
Table 4). We found that the maximum number of publications (513) are in the year 2015 (
Figure 4). There has been no study investigating the bibliometric features of literature on adverse effects related to cosmetics. So far, there has been no study in the literature with which to compare our results.