Contact allergy to lanolin: temporal changes in prevalence and association with atopic dermatitis

Contact Allergy Screening for Atopic Dermatitis

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are common inflammatory skin diseases in both children and adults that present similarly and often coexist. Patch testing is the gold standard for establishing the diagnosis of ACD and can often help distinct between the 2 conditions. Patch testing is more challenging in patients with underlying AD due to potential for angry back reactions. In this review, we discuss the current evidence and guidelines regarding the screening for contact allergies in patients with AD. We also discuss the most frequent relevant allergens in adults and children with atopic dermatitis.

Sensitization to Lanolin in North-Eastern Italy, 1997-2021: Prevalence, Risk Factors and the Impact of Occupation

Background: Direct skin contact with items containing lanolin can induce sensitization and development of contact dermatitis (CD). This multi-centric study investigated prevalence of lanolin sensitization among 30,269 outpatients from North-Eastern Italy patch tested during 1997-2021. Methods: European baseline and extended Triveneto series were applied on the upper part of patients' back and removed after 48 h. Risk factors for lanolin sensitization were investigated by multiple logistic regression analysis, reporting adjusted odds ratios (aOR) with 95% confidence interval (95%CI). Results. Overall lanolin patch test positive ratio (PTPR) was 1.64% (=501/30,629), with variability over time and by research center. The body area most frequently affected by CD were hands (36.32%), followed by face (19.52%) and legs (8.09%), with a lanolin PTPR of 1.68%, 1.37% and 3.07%, respectively. Prevalence of occupational CD was 8.24%, and 1.83% patients with occupational CD patch tested positive against lanolin. Lanolin sensitization was significantly higher in males (aOR = 1.34; 95%CI: 1.08; 1.65) and among patients with leg CD aged 49-60 years (aOR = 2.34; 95%CI: 1.20; 4.57) or older than 60 (aOR = 4.21; 95%CI: 2.59; 6.85). Sub-group analysis confirmed the significantly higher sensitization rate of older patients with leg CD, with much stronger effect size in females 61+ years old (aOR = 5.33; 95%CI 2.87; 9.89) than males in the same age group (aOR = 2.92; 95%CI: 1.34; 6.39). Moreover, female house painters were more likely to test positive to lanolin. Conclusions: The variability of lanolin PTPR over time and by research center endorsed the ongoing debate on the relevance of the respective skin reaction. Clinicians assessing patients with dermatitis should collect information on potential risk factors for lanolin sensitization, particularly use of skin care products containing the hapten. Occupational exposure to lanolin-containing varnishes should also be considered.

Lanolin

Lanolin is a complex mixture of high molecular weight esters, aliphatic alcohols, sterols, fatty acids, and hydrocarbons that has been widely used for centuries for its emollient properties. The purification of crude lanolin into lanolin wax and the processing of this wax into various derivatives began in 1882 and continue to this day with newer highly purified anhydrous lanolins. Controversy as to lanolin's allergenicity began in the 1920s and remains an issue. The most appropriate patch test preparation(s) for detecting allergy remain disputed. Detection of lanolin-induced contact dermatitis in diseased skin by patch testing on normal skin may lead to false negative results. Patients with a positive patch test to lanolin may tolerate use of lanolin on normal skin. Although lanolin is a weak sensitizer and the frequency of contact allergy to it in the European population reportedly is 0.4%, there are high-risk concomitant conditions: stasis dermatitis, leg ulcers, perianal/genital dermatitis, and atopic dermatitis (AD). Children and the elderly are also at greater risk of developing contact allergy to lanolin, partly because of comorbidities (AD and stasis dermatitis/leg ulcers, respectively). Finally, in the United States, non-Hispanic white patients are more likely than their non-Hispanic black counterparts to be lanolin allergic.

Lanolin Allergic Reactions: North American Contact Dermatitis Group Experience, 2001 to 2018

BACKGROUND

Lanolin is an important cause of allergic contact dermatitis.

OBJECTIVES

The aims of this study were to describe the epidemiology of lanolin allergy and to assess trends in patch test reactions to lanolin over time.

METHODS

This study used a retrospective analysis of patients patch tested with lanolin alcohol 30% or Amerchol L-101 50% in petrolatum by the North American Contact Dermatitis Group between 2001 and 2018 (n = 43,691).

RESULTS

Overall, 1431 (3.3%) had a positive reaction, and 1238 (2.8%) were currently relevant. Prevalence of lanolin allergy was 4.63% between 2011 and 2018 (P < 0.0001). Most lanolin-allergic patients had + (52%) reactions; 18%, and 6% had ++ and +++ reactions, respectively. Common primary anatomic sites of dermatitis were the hands (20.7%), scattered/generalized distribution (19.6%), and face (17.0%). Allergic reactions to lanolin were more common in children (4.5%) than in adults (3.2%, P = 0.0018). Compared with nonallergic patients, lanolin-allergic patients were more likely to have history of eczema or hay fever, male sex, older than 40 years, or Black race (P < 0.05). Common lanolin sources were personal care products and drugs/medications. Only 2.24% of the positive reactions were linked to occupation.

CONCLUSIONS

Lanolin sensitivity was common. Reactions were often clinically relevant and linked to personal care products and medications.

The Added Value of Patch Testing Beyond the Baseline Tray

BACKGROUND

The patch test is the standard for diagnosing allergic contact dermatitis. Standardized trays allow the examination of the most prevalent allergens, whereas customized trays are more appropriate for addressing specific allergens and require expertise. They are therefore usually performed in specialized clinics.

METHODS

We assessed the results of 4355 patch tests performed between 2012 and 2020 in a contact dermatitis clinic located in a large tertiary medical center. All patients were tested using the European baseline series and additional trays as clinically indicated. We assessed the frequency of relevant positive reactions outside the European baseline series. We then examined the added value and number of tests (NNTs) that need to be performed to elicit one relevant positive reaction per tray and common allergens.

RESULTS

Nine hundred fifty-four patients (21.9%) had 1 or more positive relevant reactions; 43.3% tested positive for an allergen outside the European baseline series (OEBS). The acrylate and fragrance trays were highly represented among the positive and relevant reactions OEBS with NNTs of 4.4 and 6.8, respectively. 2-Hydroxyethyl methacrylate is the most prevalent allergen OEBS and is considered a marker for acrylate sensitivity with a high rate of cross-reactions and concordance rate of 85%, justifying its addition to the EBS in 2018. Other highly represented allergens include chloramphenicol, 2-hydroxyethyl acrylate, and Amerchol L-101, a lanolin derivative. The cosmetics and textile trays, although often tested, have relatively low added values of 3.7% and 2.3%, respectively. Surprisingly, the cutaneous adverse drug reaction series tray (CAD-1000) yielded no positive reactions, whereas testing the patients' medication yielded positive results in 10.9% of the cases.

CONCLUSIONS

Expanded patch testing is crucial to accurately diagnose allergic contact dermatitis and almost doubles the number of patients with relevant positive reactions. Acrylate sensitivity is an emerging epidemic with a high positive reaction rate and low NNT, as is sensitivity to the allergens in the fragrance tray. 2-Hydroxyethyl methacrylate is a reliable marker for acrylate sensitivity with a concordance rate of 85%. Chloramphenicol is a common culprit and should be added to the standard tray in countries with a high usage rate. A low NNT was also observed when testing the patients' own cosmetics and medications; this should, therefore, be encouraged. The textile tray yielded a relatively high NNT; however, it should be performed when clinically indicated in the absence of a reliable marker in the EBS.

Occurrence of Allergens in Cosmetics for Sensitive Skin

Sensitive skin is characterized by symptoms such as stinging and tingling in response to stimuli that usually do not cause unpleasant sensations. Epidemiological studies show that individuals with sensitive skin are more prone to developing skin allergies, although the link between both conditions is unknown. Aiming to evaluate the presence of allergens in facial-skin products for sensitive skin, a pool of 88 cosmetic products from international brands marketed in pharmacies and parapharmacies was analyzed. A list of allergens identified in product labels was compiled and grouped according to their function. Fragrances were the most common allergens, followed by skin-conditioning agents, surfactants, and preservatives. Fragrances presenting the highest use percentages were linalool, benzyl alcohol, geraniol, and citronellol. Overall, the majority of cosmetic formulations were absent of fragrance allergens, being present only in 7% of products. Other allergens were found in most products (95%). This finding should be interpreted with caution, since many of these compounds are rare sensitizers and studies demonstrating their risk for individuals with sensitive skin are lacking. With this study, useful information for health professionals is provided to support their advice and to help consumers choosing cosmetic products.

Lipsticks History, Formulations, and Production: A Narrative Review

A considerable amount of literature has been published on several aspects of lipsticks production. To date, there is no collation of studies related to lipsticks production that has been published. This review was conducted to examine information about the history of lipsticks; ingredients used in the preparation of lipsticks, focusing on the natural and chemical ingredients; methods of preparation for the lipsticks; and the characterization of the lipsticks. A literature search for English language articles was conducted by searching electronic databases including Web of Science, Scopus, PubMed, and Google Scholar. Overall, the evidence indicates that lipsticks have been used since ancient times and are among the highest demand cosmetics. The findings of this review summarize those of earlier studies that explained the use of different types of ingredients in the manufacturing processes of lipsticks. It highlights the importance of using green technology and ingredients to fabricate lipsticks to avoid potential side effects such as skin irritation and allergy reaction.

Management of full-thickness skin grafts

Full-thickness skin grafts are a commonly used reconstructive method following Mohs micrographic surgery. The literature varies on the most appropriate methods of suturing and securing grafts as well as best practices to dress the graft postoperatively. Our objective was to review various approaches to management of full-thickness skin grafts, including suturing the graft, securing the graft, and topical emollient use on the graft postoperatively. It was found that absorbable sutures, plain gut, provide preferable outcomes with full-thickness skin grafts. The tie-over bolster is the most-used method for securing skin grafts after placement, although several other methods have demonstrated efficacy, including the polyurethane foam, sandwich, and quilting suture methods. While various topical emollients are used in the immediate postoperative period, plain white petrolatum is the least likely to form allergic contact dermatitis.

Pediatric Allergic Contact Dermatitis

Allergic contact dermatitis (ACD) affects up to 20% of adults and children, although children are infrequently patch tested. Available data suggest that children and adults, with or without atopic dermatitis, have the same prevalence of ACD. Patch testing is the gold standard for evaluation of ACD. The Pediatric Baseline Series was recently published by expert consensus for use in pediatric patch testing, with additional allergens tested as guided by history. This article examines methods of patch testing and up-to-date data on pediatric ACD. The top allergens are reviewed, and avoidance strategies are discussed.

Prevalence and Trend of Allergen Sensitization in Adults and Children with Atopic Dermatitis Referred for Patch Testing, North American Contact Dermatitis Group Data, 2001-2016

BACKGROUND

The association between atopic dermatitis (AD) and allergic contact dermatitis (ACD) is controversial.

OBJECTIVE

To analyze the prevalence, reaction strength, and trends of the most commonly positive and relevant allergens in patients with AD referred for patch testing.

METHODS

This was a retrospective analysis of 38,482 patients from the North American Contact Dermatitis Group, 2001 to 2016.

RESULTS

Most adults (56.0%) and children (52.8%) with a history of AD had a final diagnosis of ACD. Adults (66.5% vs 65.6%; χ², P = .1459) and children (61.4% vs 62.3%, P = .7074) with or without a history of AD had similar proportions of one or more allergic patch test reactions. Adults with a history of AD had a greater number of allergic patch test positive reactions than those without it (2.0 ± 2.4 vs 1.9 ± 2.3; t test, P < .0001), whereas children did not (1.5 ± 1.8 vs 1.4 ± 1.6; P = .3839). Nickel sulfate, methylisothiazolinone, formaldehyde, fragrance mix I, sodium gold thiosulfate, and thimerosal were the most common allergens in adults and children with a history of AD. In multivariable logistic regression models, adults with versus without a history of AD had increased odds of reacting to 10 of the top 25 North American Contact Dermatitis Group screening allergens. Most allergens had similar strengths of reaction in adults or children with and without a history of AD or a current AD diagnosis; cobalt, fragrance mix I, and propylene glycol had weaker reactions. In multivariable logistic regression, adults with versus without an AD history had increased odds of relevance for 10 of the 25 most currently relevant allergens, whereas children with an AD history did not have increased relevance for any specific allergens.

CONCLUSIONS

Most patients referred for patch testing with AD history had a final diagnosis of ACD. Patients with AD history had a similar likelihood of having a positive patch test reaction as those without an AD history. Adults with an AD history had a higher number of positive patch test reactions.

Clinical relevance of positive patch test reactions to lanolin: A ROAT study

Background

Lanolin is often included when patch testing for common contact allergens. The clinical relevance of a positive patch test reaction to lanolin markers is, however, still a subject for debate.

Objectives

To evaluate Amerchol L101 as a marker of lanolin allergy and investigate the clinical impact of lanolin‐containing moisturizers on healthy and damaged skin using the repeated open application test (ROAT).

Methods

Twelve test subjects and 14 controls were patch tested with Amerchol L 101 and additional lanolin markers. Subsequently, a blinded ROAT was performed on the arms of the study participants for 4 weeks. Each participant applied a lanolin‐free cream base and two different lanolin‐containing test creams twice daily on one arm with intact skin and on the other arm with irritant dermatitis, induced by sodium lauryl sulfate (SLS).

Results

Eleven test subjects (92%) had positive patch test reactions to Amerchol L 101 when retested and one test subject (8%) had a doubtful reaction. None of the study participants had any skin reactions to the ROAT on intact skin and all participants healed during the ROAT on damaged skin.

Conclusions

Lanolin‐containing emollients do not cause or worsen existing dermatitis when performing ROAT in volunteers patch test positive to Amerchol L101.

Natural ingredients in cosmetic products-A suggestion for a screening series for skin allergy

BACKGROUND

Naturally derived cosmetic product ingredients of both plant and animal origin are being included increasingly in product formulations in order to cater to consumer preferences. They may be an overlooked cause of reactions to cosmetic products in some patients with dermatitis.

OBJECTIVES

To identify naturally derived cosmetic product ingredients with allergenic potential (type I and type IV) and propose a cosmetic screening test series.

METHODS

The study was conducted in two steps. The first step was a market survey using a nonprofit application helping consumers avoid problematic substances in cosmetic products. The application contained 10 067 cosmetic products that were label checked for naturally derived cosmetic product ingredients. The second step was a literature search to examine how frequently the naturally derived ingredients were described and related to allergic reactions in cosmetics or other topically administered products.

RESULTS

We identified 121 different naturally derived cosmetic product ingredients that were included in at least 30 cosmetic products. In total, 22 ingredients were selected for a screening test series.

CONCLUSIONS

We propose a supplemental patch test and a prick test screening series with naturally derived cosmetic product ingredients for patients with skin reactions to cosmetic products, aiming to identify a cause in more patients than is currently possible.

Allergic Contact Dermatitis Secondary to Moisturizers

Background: Moisturizers are cosmetic products used routinely to manage various skin conditions. Even though moisturizers are often thought to have minimal or no adverse reactions, allergic contact dermatitis (ACD) to these products can develop in some cases. Methods: We studied ingredients included in 3 of the most commonly used moisturizer brands, identified their presence in standard patch testing series, and evaluated their allergenic potential, categorizing the allergens as frequent or infrequent. The standard patch testing series used as reference were the Thin-layer Rapid Use Epicutaneous patch test (T.R.U.E. test), the North American Contact Dermatitis Group (NACDG) screening standard series, and the American Contact Dermatitis Society (ACDS) core allergen series. Results: Aveeno, Cetaphil, and Cerave products had a total of 12, 14, and 9 potential allergens, respectively, the majority of which were infrequent and not included in standard patch testing series. Conclusion: Being aware of the allergenic potential of commonly used moisturizers may help healthcare providers when evaluating patients with ACD. Further testing is recommended in a targeted manner when suspecting ACD with negative standard patch testing series or when ACD is refractory to treatment.

Contact Allergy-Emerging Allergens and Public Health Impact

Contact allergy (sensitisation) and allergic contact dermatitis (ACD) resulting from it have a considerable public health impact. For the present review, all pertinent articles were systematically searched via Medline and Web of Science™; additionally, all available issues of the journals "Contact Dermatitis" and "Dermatitis" were manually searched, covering the years 2018-2019, thereby extending and re-focusing a previous similar review. New allergens, or previously described allergens found in a new exposure context or of other current importance, are described in sections according to substance classes, e.g., metals, preservatives, fragrances. As a common finding in many investigations, a lack of information on product composition has been noted, for instance, regarding a newly described allergen in canvas shoes (dimethylthiocarbamylbenzothiazole sulfide) and, most notably, absence of co-operation from manufacturers of glucose-monitoring devices and insulin pumps, respectively. These latter devices have been shown to cause severe ACD in a considerable number of diabetic patients caused by the liberation of isobornyl acrylate and N,N'-dimethylacrylamide, respectively, as demonstrated by an international collaboration between dermatologists and chemists. Improved and complete ingredient labelling for all types of products, and not just cosmetics, must be put on the legislative agenda.

Diagnosing lanolin contact allergy with lanolin alcohol and Amerchol L101

Background

The prevalence of lanolin contact allergy in dermatitis patients varies from 1.2% to 6.9%. Different lanolin derivatives are used in patch testing.

Objectives

To determine which combination of lanolin derivatives is most effective in patch testing for the diagnosis of lanolin contact allergy.

Methods

A retrospective analysis of patients patch tested between 2016 and 2017 was performed. Patients were eligible if they had been tested with lanolin alcohol 30% pet., Amerchol L101 50% pet., and a supplementary series containing other lanolin derivatives. Lanolin alcohol and Amerchol L101 were tested in duplicate.

Results

Of 594 patients, 28.6% (95% confidence interval [CI]: 25.1%‐32.3%) had a positive patch test reaction to at least one lanolin derivative. Reactions to lanolin alcohol (14.7%, 95%CI: 11.3%‐18.2%) and Amerchol L101 (15.0%, 95%CI: 11.5%‐18.5%) were common in the routinely tested series. Reactions to other test preparations were significantly less frequent (P < 0.05). The addition of Amerchol L101 to lanolin alcohol significantly increased the number of positive cases (odds ratio 1.79, P < 0.001).

Conclusions

The combination of lanolin alcohol and Amerchol L101 is effective in patch testing for the diagnosis of lanolin contact allergy. Routinely testing with other lanolin derivatives may not be worthwhile, as it detects only a few additional patients.

Emollient treatment of atopic dermatitis: latest evidence and clinical considerations

Aim

To review current classes of emollients in the market, their clinical efficacy in atopic dermatitis (AD) and considerations for choice of an emollient.

Methods

PubMed Clinical Queries under Clinical Study Categories (with Category limited to Therapy and Scope limited to Narrow) and Systematic Reviews were used as the search engine. Keywords of ‘emollient or moisturizer’ and ‘atopic dermatitis’ were used.

Overview of findings

Using the keywords of ‘emollient’ and ‘atopic dermatitis’, there were 105 and 36 hits under Clinical Study Categories (with Category limited to Therapy and Scope limited to Narrow) and Systematic Reviews, respectively. Plant-derived products, animal products and special ingredients were discussed. Selected proprietary products were tabulated.

Conclusions

A number of proprietary emollients have undergone trials with clinical data available on PubMed-indexed journals. Most moisturizers showed some beneficial effects, but there was generally no evidence that one moisturizer is superior to another. Choosing an appropriate emollient for AD patients would improve acceptability and adherence for emollient treatment. Physician’s recommendation is the primary consideration for patients when selecting a moisturizer/emollient; therefore, doctors should provide evidence-based information about these emollients.