Experimental inhalation of fragrance allergens in predisposed subjects: effects on skin and airways

Hair Product Allergy: A Review of Epidemiology and Management

Allergy to hair products is an increasingly common issue among people given the exposure to these products on a daily basis. Allergic reactions could be in the form of delayed-type contact dermatitis or the form of immediate-type hypersensitivity reactions. Hair products contain many ingredients and chemicals that patients may have allergies to, but common allergens are hair dyes, fragrances, persulfate salts, ammonium thioglycolate, coconut fatty acid derivatives, and acrylates. Allergy to hair dye is the most common followed by other allergens such as fragrances and persulfate salts. We discussed testing for hair dye allergy along with suggestions for alternative hair dyes that patients may use. Allergy to topical scalp medications is also seen in patients using those products. Allergy to topical minoxidil is seen more often due to the increased use of minoxidil sprays and foams among patients to increase hair growth. We will discuss in this review the diagnosis and alternatives for patients with minoxidil allergy. Hairdressers are at higher risk of allergy to hair products compared to the general population due to prolonged exposure to allergens and specific measures should be implemented to minimize the hazards of exposure.

Exposure limits for indoor volatile substances concerning the general population: The role of population-based differences in sensory irritation of the eyes and airways for assessment factors

Assessment factors (AFs) are essential in the derivation of occupational exposure limits (OELs) and indoor air quality guidelines. The factors shall accommodate differences in sensitivity between subgroups, i.e., workers, healthy and sick people, and occupational exposure versus life-long exposure for the general population. Derivation of AFs itself is based on empirical knowledge from human and animal exposure studies with immanent uncertainty in the empirical evidence due to knowledge gaps and experimental reliability. Sensory irritation in the eyes and airways constitute about 30-40% of OELs and is an abundant symptom in non-industrial buildings characterizing the indoor air quality and general health. Intraspecies differences between subgroups of the general population should be quantified for the proposal of more 'empirical' based AFs. In this review, we focus on sensitivity differences in sensory irritation about gender, age, health status, and vulnerability in people, based solely on human exposure studies. Females are more sensitive to sensory irritation than males for few volatile substances. Older people appear less sensitive than younger ones. However, impaired defense mechanisms may increase vulnerability in the long term. Empirical evidence of sensory irritation in children is rare and limited to children down to the age of six years. Studies of the nervous system in children compared to adults suggest a higher sensitivity in children; however, some defense mechanisms are more efficient in children than in adults. Usually, exposure studies are performed with healthy subjects. Exposure studies with sick people are not representative due to the deselection of subjects with moderate or severe eye or airway diseases, which likely underestimates the sensitivity of the group of people with diseases. Psychological characterization like personality factors shows that concentrations of volatile substances far below their sensory irritation thresholds may influence the sensitivity, in part biased by odor perception. Thus, the protection of people with extreme personality traits is not feasible by an AF and other mitigation strategies are required. The available empirical evidence comprising age, lifestyle, and health supports an AF of not greater than up to 2 for sensory irritation. Further, general AFs are discouraged for derivation, rather substance-specific derivation of AFs is recommended based on the risk assessment of empirical data, deposition in the airways depending on the substance's water solubility and compensating for knowledge and experimental gaps. Modeling of sensory irritation would be a better 'empirical' starting point for derivation of AFs for children, older, and sick people, as human exposure studies are not possible (due to ethical reasons) or not generalizable (due to self-selection). Dedicated AFs may be derived for environments where dry air, high room temperature, and visually demanding tasks aggravate the eyes or airways than for places in which the workload is balanced, while indoor playgrounds might need other AFs due to physical workload and affected groups of the general population.

Effects of increased recirculation air rate and aircraft cabin occupancy on passengers' health and well-being - Results from a randomized controlled trial

BACKGROUND

Aircraft cabins are special environments. Passengers sit in close proximity in a space with low pressure that they cannot leave. The cabin is ventilated with a mixture of outside and recirculated air. The volume of outside air impacts the carbon footprint of flying. Higher recirculation air rates could be considered to save energy and divert less kerosene from producing thrust.

OBJECTIVES

To investigate whether higher recirculation air rates in aircraft cabins negatively affect passengers' health and well-being and if occupancy plays a role in this.

METHODS

In a 2 (occupancy: full and half-occupied) X 4 (ventilation regime) factorial design with stratified randomization, participants were exposed in an aircraft segment in a low-pressure tube during a 4-h simulated flight. Ventilation regimes consisted of increasing proportions of recirculated air up to a maximum CO₂ concentration of 4200 ppm. Participants rated comfort, health symptoms, and sleepiness multiple times. Heart rate (variability), as stress marker, was measured continuously.

RESULTS

559 persons representative of flight passengers regarding age (M = 42.7, SD = 15.9) and sex (283 men) participated. ANCOVA results showed hardly any effect of both factors on self-reported health symptoms, strong main effects of occupancy on comfort measures, and interaction effects for sleepiness and physiological stress parameters: Participants in the half-occupied cabin hardly reacted to increased recirculation air rates and show overall more favorable responses. Participants in the fully occupied cabin reported higher sleepiness and had stress reactions when the recirculation air rate was high.

DISCUSSION

This large-scale RCT shows the importance of occupancy, a previously neglected factor in indoor air research. The proximity of other people seems to increase stress and exacerbate reactions to air quality. Further studies on causal pathways are needed to determine if recirculation air rates can be increased to reduce the carbon footprint of flying without detrimental effects on passengers.

Analysis of Fragrance Allergens in Personal Care Products, Toys, and Water Samples: A Review

Fragrance allergens (FAs) refer to these volatile or semi-volatile fragrance compounds that can cause irritation and negative reactions. A large number of emerging FAs are widely used in household goods, and cause contact allergy or allergic contact dermatitis in eczema population and the general population. It shows an increasing prevalence and is regarded as a concern to public health. Recently, more and more studies have focused on the analytical methods of FAs in a variety of samples with different matrices. Therefore, a systematic and comprehensive overview of recent progress of analysis of FAs in various samples is needed. In this review, the physical and chemical properties, applications, hazards, and the recent advances of sample preparation and determination methods of common FAs in personal care products, toys, and water samples are systematically and comprehensively summarized. Meanwhile, this review also discusses the advantages and limitations of different sample pretreatment and detection methods, thus offering a deep-going discussion of the development and future trends in this area.

Selected essential oils and their mechanisms for therapeutic use against public health disorders. An overview

Today, the numbers of people suffering from lifestyle diseases like diabetes, obesity, allergies and depression increases mainly in industrialised states. That does not only lower patients' quality of life but also severely stresses the health care systems of these countries. Essential oils (EO) have been in use as therapeutic remedies for centuries against various complaints, but still their effectiveness is being underestimated. In the last decades, a great number of controlled studies have supported efficacy of these volatile secondary plant metabolites for various therapeutic indications. Besides others, EO has antidepressant, anti-obesity, antidiabetic, antifirogenic and antiallergic effects. In this review the pharmacological mechanisms for selected EO are summarised and discussed with the main attention on their impact against public health disorders. Additionally, toxicity of these oils as well as possible drug interactions is presented.

Fragrance inhalation and adverse health effects: The question of causation

The toxicology of fragrance materials is largely well understood. Although most are benign, a minority have the potential to cause adverse health effects, notably allergic contact dermatitis resulting from skin sensitization. As a consequence, industry guidelines have banned certain materials and strictly limited the use of others. Recently, data have been published that have been interpreted to suggest that inhalation of fragrances is associated with the occurrence of a variety of health effects, ranging from headaches to asthma attacks. In this review, the evidence basis for these assertions is examined critically and the biological basis and mechanistic plausibility for causation by fragranced products of these health effects is explored. This review concludes that respiratory effects, including irritation and allergy appear highly unlikely to occur by this route. While some sensory/psychosomatic effects are possible, this does not explain the very high rates of adverse effects reported in the recently published questionnaire studies, which this review concludes are more likely to be attributed to methodological weaknesses. Ultimately, it is concluded that adverse health effects arising from fragrance inhalation are uncommon and remain to be identified and confirmed by methodologically rigorous epidemiological investigations supported by a convincing biological and mechanistic basis.

Psychological and cognitive effects of laser printer emissions: A controlled exposure study

The possible impact of ultrafine particles from laser printers on human health is controversially discussed although there are persons reporting substantial symptoms in relation to these emissions. A randomized, single-blinded, cross-over experimental design with two exposure conditions (high-level and low-level exposure) was conducted with 23 healthy subjects, 14 subjects with mild asthma, and 15 persons reporting symptoms associated with laser printer emissions. To separate physiological and psychological effects, a secondary physiologically based categorization of susceptibility to particle effects was used. In line with results from physiological and biochemical assessments, we found no coherent, differential, or clinically relevant effects of different exposure conditions on subjective complaints and cognitive performance in terms of attention, short-term memory, and psychomotor performance. However, results regarding the psychological characteristics of participants and their situational perception confirm differences between the participants groups: Subjects reporting symptoms associated with laser printer emissions showed a higher psychological susceptibility for adverse reactions in line with previous results on persons with multiple chemical sensitivity or idiopathic environmental intolerance. In conclusion, acute psychological and cognitive effects of laser printer emissions were small and could be attributed only to different participant groups but not to differences in exposure conditions in terms of particle number concentrations.

Effects by inhalation of abundant fragrances in indoor air - An overview

Odorous compounds (odors) like fragrances may cause adverse health effects. To assess their importance by inhalation, we have reviewed how the four major abundant and common airborne fragrances (α-pinene (APN), limonene (LIM), linalool (LIL), and eugenol (EUG)) impact the perceived indoor air quality as odor annoyance, sensory irritation and sensitization in the airways. Breathing and cardiovascular effects, and work performance, and the impact in the airways of ozone-initiated gas- and particle phase reactions products have also been assessed. Measured maximum indoor concentrations for APN, LIM and LIL are close to or above their odor thresholds, but far below their thresholds for sensory irritation in the eyes and upper airways; no information could be traced for EUG. Likewise, reported risk values for long-term effects are far above reported indoor concentrations. Human exposure studies with mixtures of APN and LIM and supported by animal inhalation models do not support sensitization of the airways at indoor levels by inhalation that include other selected fragrances. Human exposure studies, in general, indicate that reported lung function effects are likely due to the perception rather than toxic effects of the fragrances. In general, effects on the breathing rate and mood by exposure to the fragrances are inconclusive. The fragrances may increase the high-frequency heart rate variability, but aerosol exposure during cleaning activities may result in a reduction. Distractive effects influencing the work performance by fragrance/odor exposure are consistently reported, but their persistence over time is unknown. Mice inhalation studies indicate that LIM or its reaction mixture may possess anti-inflammatory properties. There is insufficient information that ozone-initiated reactions with APN or LIM at typical indoor levels cause airway effects in humans. Limited experimental information is available on long-term effects of ozone-initiated reaction products of APN and LIM at typical indoor levels.

Work-related asthma among professional cleaning women

The job of cleaning has developed dynamically as a working service, and women constitute the majority of all professional cleaning workers. Cleaners are at an increased risk of work-related asthma (WRA). This study characterizes work-related respiratory symptoms reported by female cleaners, evaluates any associated factors of WRA, and shows diagnostic management of medical certification. The study group comprised 50 professional cleaning women referred to our Occupational Diseases Department due to suspicion of occupational asthma (OA). A questionnaire, skin prick tests, serum specific IgE antibodies, and specific inhalant challenge were performed in all of the participants. Work-related asthma was recognized in 46% of symptomatic cleaners, of whom 15 were considered as having work-exacerbated asthma (WEA) and 8 as having OA. Sensitization to latex and disinfectants played an important role as a causative agent in OA of cleaners.

RIFM fragrance ingredient safety assessment, isoeugenol, CAS Registry Number 97-54-1

The use of this material under current use conditions is supported by the existing information. This material was evaluated for genotoxicity, repeated dose toxicity, developmental toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity, skin sensitization potential, as well as, environmental safety. Repeated dose toxicity was determined to have the most conservative systemic exposure derived NO[A]EL of 37.5 mg/kg/day. A gavage 13-week subchronic toxicity study conducted in mice resulted in a MOE of 5769 while considering 38.4% absorption from skin contact and 100% from inhalation. A MOE of >100 is deemed acceptable.

Fragrance allergic contact dermatitis

Fragrances are a common cause of allergic contact dermatitis in Europe and in North America. They can affect individuals at any age and elicit a spectrum of reactions from contact urticaria to systemic contact dermatitis. Growing recognition of the widespread use of fragrances in modern society has fueled attempts to prevent sensitization through improved allergen identification, labeling, and consumer education. This review provides an overview and update on fragrance allergy. Part 1 discusses the epidemiology and evaluation of suspected fragrance allergy. Part 2 reviews screening methods, emerging fragrance allergens, and management of patients with fragrance contact allergy. This review concludes by examining recent legislation on fragrances and suggesting potential additions to screening series to help prevent and detect fragrance allergy.

Fate and transport of fragrance materials in principal environmental sinks

Fragrance materials are widely present in the environment, such as air, water, and soil. Concerns have been raised due to the increasing utilization and suspected impact on human health. The bioaccumulating property is considered as one of the causes of the toxicity to human beings. The removal of fragrance materials from environmental sinks has not been paid enough attention due to the lack of regulation and research on their toxicity. This paper provides systematic information on how fragrance materials are transferred to the environment, how do they affect human lives, and what is their fate in water, wastewater, wastewater sludge, and soil.

Fragrance materials in asthma: a pilot study using a surrogate aerosol product

OBJECTIVE

Many household products contain fragrances. Little is known about exposure to fragrances on human health, particularly within the airways. This study aimed to evaluate how common household fragrance products (i.e. air fresheners, cleaning products) affect people with asthma, who frequently report sensitivity to these products. Many of these products have volatile organic compounds or semi-volatile organic compounds. This study evaluated nine fragrance materials in an aerosol formulation to assess effects on airway physiology, airway inflammation and symptom perception in normal controls and those with asthma.

METHODS

The effects of fragrances were evaluated in people without asthma, people with mild asthma and people with moderate asthma in a four-way crossover placebo-controlled study. Subjects were exposed twice to a fragranced aerosol and twice to a placebo aerosol (15 and 30 min each). Subjects completed a questionnaire for 29 symptoms during and up to 3 h after each exposure scenario. Spirometry was performed prior to and 3 h post-exposure; sputum induction was conducted 3 h post-exposure.

RESULTS

Nasal symptoms showed the greatest frequency of response in all three subject groups, and moderate asthmatics reported the greatest symptom severity and symptom types. No significant differences were noted in physiology or cellular inflammation.

CONCLUSION

A trend for increased symptoms was noted in moderate asthmatics, suggesting that asthma severity may play a factor in fragrance sensitivity.

The association between personal care products and lung function

PURPOSE

Chemical exposures are important determinants of respiratory health. The objective of the present study was to determine the association between the use of personal care products, which may contain respirable components, and lung function.

METHODS

Using questionnaire and spirometry data collected during the Canadian Health Measures population survey, the association was tested between 1-second forced expiratory volume (FEV(l)) and forced vital capacity (FVC) expressed as a percentage of predicted, and the frequency of use of personal care products categorized as eye makeup, fragrances, hairstyle products, lipstick, and scented body products.

RESULTS

Five thousand sixteen of the 5604 participants in the survey reported using at least one personal care product in the past 3 months. Among men and women, an interquartile increase in hairstyle products was associated with an approximate 2% decrease in both FEV(1) and FVC (P < .05). Among women, each product category was associated with a significant decrease in lung function with the largest observed effect being a 4.08% (95% confidence interval, 7.71-0.45) decrease in FVC associated with an interquartile range increase in the frequency of use of scented body products.

CONCLUSIONS

This study provides data suggesting that using personal care products may have a small adverse effect on lung function. Further research is warranted to investigate this possibility.

Indoor air pollutants in office environments: assessment of comfort, health, and performance

Concentrations of volatile organic compounds (VOCs) in office environments are generally too low to cause sensory irritation in the eyes and airways on the basis of estimated thresholds for sensory irritation. Furthermore, effects in the lungs, e.g. inflammatory effects, have not been substantiated at indoor relevant concentrations. Some VOCs, including formaldehyde, in combination may under certain environmental and occupational conditions result in reported sensory irritation. The odour thresholds of several VOCs are low enough to influence the perceived air quality that result in a number of acute effects from reported sensory irritation in eyes and airways and deterioration of performance. The odour perception (air quality) depends on a number of factors that may influence the odour impact. There is neither clear indication that office dust particles may cause sensory effects, even not particles spiked with glucans, aldehydes or phthalates, nor lung effects; some inflammatory effects may be observed among asthmatics. Ozone-initiated terpene reaction products may be of concern in ozone-enriched environments (≥0.1mg/m(3)) and elevated limonene concentrations, partly due to the production of formaldehyde. Ambient particles may cause cardio-pulmonary effects, especially in susceptible people (e.g. elderly and sick people); even, short-term effects, e.g. from traffic emission and candle smoke may possibly have modulating and delayed effects on the heart, but otherwise adverse effects in the airways and lung functions have not been observed. Secondary organic aerosols generated in indoor ozone-initiated terpene reactions appear not to cause adverse effects in the airways; rather the gaseous products are relevant. Combined exposure to particles and ozone may evoke effects in subgroups of asthmatics. Based on an analysis of thresholds for odour and sensory irritation selected compounds are recommended for measurements to assess the indoor air quality and to minimize reports of irritation symptoms, deteriorated performance, and cardiovascular and pulmonary effects.

Inhalation exposure of children to fragrances present in scented toys

When utilized in the perfuming of children's toys, fragrances capable of inducing contact allergy in human skin may also become bioavailable to children via the inhalation route. The aim of this study was to determine the area-specific emission rates of 24 fragrances from a plasticized PVC reference material that was meant to mimic a real plastic toy. This material was introduced into an emission chamber for 28 days at handling conditions or at worst-case conditions. As a result, fragrances can be separated into three categories according to their emission rates ranging from 0.0041 to 16.2 mg/m² × h, i.e., highly volatile, semivolatile, and low-volatile compounds. Compounds of the first and second categories were monitored with decreasing emission rates. Substances of the third category were detected with increasing emission rates over time. Further, higher temperatures led to higher emission rates. The emission concentration of fragrances from four real scented toys varied between 1.10 and 107 μg/m³ at day 1 in the test chamber. Therefore, short-term inhalation exposure to fragrances originating from toys was in the range of 0.53-2700 ng/kg BW/d for the children of age 1 and older. Long-term exposure to these fragrances was calculated in the range of 2.2-220 ng/kg BW/d.

PRACTICAL IMPLICATIONS

Besides household products and cosmetics, fragrances can be found in toys for children. Some fragrances are known contact allergens in the skin, but there is a lack of information on their effects in the human respiratory tract. Here, we analyzed and categorized fragrances present in a plasticized PVC reference material according to their emission profiles and volatility. We also demonstrate that volatile fragrances are being emitted from real toys and thus may get inhaled under consumer conditions to different extents.

Contact allergy and human biomonitoring--an overview with a focus on metals

Humans are widely exposed to chemicals. Today, there is an increased acknowledgement of the importance of measuring human and environmental exposures to man-made or refined chemicals. Different approaches have been applied over time, but during the past 25 years, there has been a general trend towards the use of human biomonitoring. A few studies have used human biomonitoring methodology to track contact allergens together with information on patch test reactivity. Hypothetically, the internal load of reactive chemicals might modify the immune response to haptens and the propensity to sensitize and elicit allergic contact dermatitis or develop tolerance. This review offers a general overview of human biomonitoring, including information about its typical application and methodology. Furthermore, studies that have attempted to perform simultaneous biomonitoring and patch testing are reviewed. It is concluded that all studies conducted until the present have focused on one or two routes of exposure (typically skin and oral exposure, but also skin and airway exposure), whereas no studies have investigated all routes at the same time. Also, there is a need for prospective studies, as all epidemiological studies so far have been cross-sectional.