Lanolin: The 2023 American Contact Dermatitis Society Allergen of the Year.

In 2023, lanolin was named the American Contact Dermatitis Society Allergen of the Year. Despite its widespread use in personal care products and industrial goods, lanolin is thought to be a rare sensitizer in patients with healthy skin; however, those with chronic inflammatory skin conditions are at a higher risk for allergic contact dermatitis (ACD) to lanolin. The proper patch test formulation for lanolin is a source of contention. In this article, we discuss ACD to lanolin with a focus on its paradoxical nature and the subtleties to consider when patch testing to this controversial allergen.

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.

Contact Allergens in Prescription Topical Ophthalmic Medications.

BACKGROUND/OBJECTIVE: Both active and inactive ingredients in topical ophthalmic agents may cause allergic contact dermatitis. Here, we examined ingredients in prescription topical ophthalmic medications available in the United States. METHODS: A comprehensive list of topical ophthalmic medications was generated using AccessPharmacy. Categories included antiglaucoma, antibiotic, antibiotic/corticosteroid, corticosteroid, antiviral, antifungal, mydriatic, and miotic agents. For each formulation, ingredients were investigated using the National Institutes of Health US National Library of Medicine database and/or manufacturer websites. Counts and proportions were calculated for inactive ingredients, including those in the American Contact Dermatitis Society (ACDS) Core 90 Allergen Series. RESULTS: Two hundred sixty-four unique prescription ophthalmic medications met the inclusion criteria. The most common ACDS Core 90 allergen/cross-reactor inactive ingredient was benzalkonium chloride (68.1%, 180/264), followed by sorbates (11.7%, 31/264), parabens (6.8%, 18/264), sodium metabisulfite (3.8%, 10/264), propylene glycol (3.0%, 8/264), and lanolin (3.0%, 8/264). Approximately 21% (20.8%, 55/264) of products had no ACDS Core 90 allergens/cross-reactor inactive ingredients. The most common ACDS Core 90 allergen/cross-reactor active ingredients were aminoglycoside antibiotics, bacitracin/polymyxin B, and corticosteroids. Important non-ACDS Core 90 allergens included inactive ingredients, such as EDTA 28.0% and thimerosal 2.7%, as well as active ingredients, especially ß-blockers. CONCLUSIONS: Benzalkonium chloride, sodium metabisulfite, propylene glycol, and lanolin were common inactive ingredient allergens. Most ophthalmic categories had low allergen formulations available for patients with contact allergy.

Iatrogenic allergic contact dermatitis in the (peri)anal and genital area.

BACKGROUND: Allergic contact dermatitis (ACD) from topical medication often occurs in occluded areas, for example, with wound treatment, but also in certain body locations, such as the anogenital area. OBJECTIVES: To investigate the demographics and specific lesion location of patients with ACD from topical drugs applied onto the (peri)anal/genital area, and to identify the respective causal topical pharmaceutical products and ingredients involved. METHODS: From January 2000 to December 10, 2018, 532 patients were tested with the baseline series, sometimes with additional series, and the topical medication used along with the ingredients. The relevant data were extracted from our electronic databases developed in-house. RESULTS: Forty-four patients (9%) out of 473 patients suffering from lesions in the (peri)anal/genital area had positive patch test results to topical drug preparations and/or their ingredients, sometimes in association with cosmetics for intimate hygiene. The most frequent sensitizing active principles were local anaesthetics and corticosteroids, while wool alcohols and to a minor extent benzoic acid were the most frequent culprits among the vehicle components and preservative agents, respectively. CONCLUSIONS: The local conditions (eg, occlusion, sweating, moist) in the anogenital area may favour skin sensitization to topical medication used to treat various skin diseases.

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.

Allergic Contact Dermatitis to Operating Room Scrubs and Disinfectants.

BACKGROUND: Both surgical personnel and patients undergoing procedures are exposed regularly to different antiseptic chemicals in various forms. Little is known about the ingredients in these antiseptics and the risk these products may provoke allergic contact dermatitis. OBJECTIVE: The aim of the study was to identify and characterize common allergens in surgical scrubs and patient surgical cleansers that health care workers and surgical patients may encounter in the perioperative period. METHODS: DailyMed website was searched using numerous terms for surgical disinfectants. Products used for health care worker handwashing/scrubbing or patient surgical cleansing/disinfecting were included. Each product's ingredients were recorded; those found on the 2017 American Contact Dermatitis Society (ACDS) Core Allergen Series were noted from each product. CONCLUSIONS: A total of 1940 products were identified, of which 267 were included in the analysis. A total of 66.3% contained iodine, 25.8% contained chlorhexidine digluconate, and 2.6% contained chloroxylenol. Within the group analyzed, 1586 ingredients were identified. Of these, 241 were ACDS Core Series allergens. Most products contained a single ACDS allergen. There were significant differences in allergens based on product type and active ingredient, with iodine-containing products having the fewest number of allergens. The most common ACDS allergens found were cocamide diethanolamide (22.5%), fragrance (21.7%), lanolin (19.5%), propylene glycol (6.7%), alkyl glucosides (6.0%), and sorbic acid derivatives (5.6%).

The Low Prevalence of Allergic Contact Dermatitis Using a Petrolatum Ointment Containing Lanolin Alcohol

Lanolin alcohol is a high cholesterol containing naturally derived material used as a skin protectant in wound healing petrolatum-based ointments. It is a highly purified fraction of lanolin wool wax that has been identified as a possible cause of allergic contact dermatitis. This 3-center study enrolled 499 subjects who underwent a variety of in-office surgical procedures followed by application of a wound healing ointment containing lanolin alcohol without antibiotics. No allergic contact dermatitis was identified in the 499 subjects who completed the study. The lack of allergic contact dermatitis observed may be due to the proprietary highly purified lanolin alcohol utilized in the study formulation. This is not the lanolin alcohol preparation found on the standard dermatology patch test tray. Not all lanolin alcohols are equal. This is an important consideration when examining the reported incidence of allergic contact dermatitis to lanolin alcohol and the absence of allergic contact dermatitis demonstrated in this research. J Drugs Dermatol. 2019;18(10):1002-1004.

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.

Safety Assessment of Polyether Lanolins as Used in Cosmetics.

The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) assessed the safety of 39 polyether lanolin ingredients as used in cosmetics. These ingredients function mostly as hair conditioning agents, skin conditioning agent-emollients, and surfactant-emulsifying agents. The Panel reviewed available animal and clinical data, from previous CIR safety assessments of related ingredients and components. The similar structure, properties, functions, and uses of these ingredients enabled grouping them and using the available toxicological data to assess the safety of the entire group. The Panel concluded that these polyether lanolin ingredients are safe in the practices of use and concentration as given in this safety assessment.

Prevalence of Contact Allergens in Personal Care Products for Babies and Children.

BACKGROUND: Personal care products marketed for babies and children are often regarded as "safe" or "gentle." However, little is known about the prevalence of contact allergens in these types of products. OBJECTIVE: This study assessed the prevalence of important sensitizers in personal care products marketed for babies and children. A secondary objective of this study was to determine whether a product's cost correlates with content of sensitizing ingredients. METHODS: The ingredient lists of 533 unique personal care products were analyzed for presence of fragrance, betaines, propylene glycol, methylchloroisothiazolinone, methylisothiazolinone, formaldehyde, lanolin, and neomycin. Price per ounce was determined for each product as well. CONCLUSIONS: Most personal care products for babies and children contain 1 or more sensitizers. Products containing more sensitizers tend to cost less than those without any sensitizing ingredients.

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

BACKGROUND: Lanolin has been tested as lanolin alcohols (30% pet.) in baseline patch test series since 1969, and this has shown clinically relevant allergic contact dermatitis cases. OBJECTIVES: To investigate the temporal development of lanolin allergy (i.e. positive reaction to lanolin alcohols and/or Amerchol™ L-101), and the association between contact allergy to lanolin and patient characteristics from the MOAHLFA index. METHODS: A retrospective observational study of consecutively patch tested dermatitis patients (n = 9577) between 1 January 2004 and 31 December 2015 with lanolin alcohols 30% pet. and Amerchol™ L-101 50% pet. was performed. RESULTS: The prevalence of lanolin allergy increased from 0.45% in 2004 to 1.81% in 2015. In age-adjusted and sex-adjusted analyses, weak, significant associations were found between atopic dermatitis and lanolin and lanolin alcohols allergy, respectively, but no association with Amerchol™ L-101 allergy was found. Among 9286 dermatitis patients who were tested with both allergens, 108 had a positive test reaction to either lanolin alcohols or Amerchol™ L-101, whereas only 29 patients had positive test reactions to both markers. CONCLUSIONS: The prevalence of lanolin contact allergy has increased over a 12-year period, and inclusion of Amerchol™ L-101 will increase the chance of detecting lanolin contact allergy. Patch testing with lanolin is helpful in atopics with dermatitis and suspected cosmetic allergy.

Debunking the Myth of Wool Allergy: Reviewing the Evidence for Immune and Non-immune Cutaneous Reactions.

Although wool is commonly believed to cause irritant (non-immune) and hypersensitivity (immune) cutaneous reactions, the evidence basis for this belief and its validity for modern garments have not been critically examined. Publications from the last 100 years, using MEDLINE and Google Scholar, were analysed for evidence that wool causes cutaneous reactions, both immune-mediated (atopic dermatitis exacerbation, contact urticaria, allergic contact dermatitis) and non-immune-mediated (irritant contact dermatitis, itch). Secondary aims of this paper were to examine evidence that lanolin and textile-processing additives (formaldehyde, chromium) cause cutaneous reactions in the context of modern wool-processing techniques. Current evidence does not suggest that wool-fibre is a cutaneous allergen. Furthermore, contact allergy from lanolin, chromium and formaldehyde is highly unlikely with modern wool garments. Cutaneous irritation from wool relates to high fibre diameters (≥ 30-32 µm). Superfine and ultrafine Merino wool do not activate sufficient c-fibres to cause itch, are well tolerated and may benefit eczema management.

The current spectrum of contact sensitization in patients with chronic leg ulcers or stasis dermatitis - new data from the Information Network of Departments of Dermatology (IVDK).

BACKGROUND: Patients with lower leg dermatitis, chronic venous insufficiency or chronic leg ulcers have a high prevalence of contact sensitization. OBJECTIVES: To identify the current spectrum of contact allergens in these patients. PATIENTS AND METHODS: Data of the Information Network of Departments of Dermatology on 5264 patients with the above diagnoses from the years 2003 to 2014 (study group) were compared with data on 4881 corresponding patients from 1994 to 2003 (historical control group) and with a current control group without these diagnoses (n = 55 510). RESULTS: Allergic contact dermatitis was diagnosed less frequently in the study group than in the historical control group (25.9% versus 16.9%; p < 0.001), and contact sensitization to most allergens had declined. The allergen spectrum, however, was largely unchanged. Important allergens are Myroxylon pereirae (balsam of Peru) (14.8% positive reactions), fragrance mix I (11.4%), lanolin alcohol (7.8%), colophonium (6.6%), neomycin sulfate (5.0%), cetearyl alcohol (4.4%), oil of turpentine (3.1%), and paraben mix (2.6%). Patch testing with additional series showed sensitization to Amerchol L-101 (9.7%), tert-butyl hydroquinone (8.7%), framycetin sulfate (5.0%), and gentamicin sulfate (3.1%). CONCLUSIONS: Topical preparations for treating the above-mentioned conditions should not contain fragrances, Myroxylon pereirae, and colophonium. The special allergen spectrum has to be considered in patch testing.

Potential Allergens in Disposable Diaper Wipes, Topical Diaper Preparations, and Disposable Diapers: Under-recognized Etiology of Pediatric Perineal Dermatitis.

BACKGROUND: Allergic contact dermatitis in young children may be an under-recognized cause of perineal dermatitis. The diapered infant skin is uniquely susceptible to allergic contact dermatitis because of more permeable neonatal skin, a moist environment, frequent contact with irritants and resultant skin barrier breakdown, and exposure to topical products such as diaper wipes, diaper preparations, and disposable diapers. To our knowledge, potential allergens in these products have not been thoroughly catalogued or studied. OBJECTIVE: We explore and review potential allergenic ingredients in diaper wipes, topical diaper preparations, and disposable diapers. METHOD: We analyzed 63 diaper wipes, 41 topical diaper preparations, and the 3 top selling diaper brands available from two of the largest retailers in the United States. Each potential allergen is discussed, and epidemiologic studies of rates of sensitization to potential allergens in children are also reported. CONCLUSIONS: Botanical extracts, including members of the Compositae family, were the most commonly represented potential allergen in both diaper wipes and topical preparations. Other potential allergens identified with high frequency include α-tocopherol, fragrances, propylene glycol, parabens, iodopropynyl butylcarbamate, and lanolin. Frequent culprits such as formaldehyde releasers and methylchloroisothiazolinone/methylisothiazolinone were not prevalent in our analyzed products.

North American contact dermatitis group patch test results: 2011-2012.

BACKGROUND: Patch testing is an important diagnostic tool for assessment of allergic contact dermatitis (ACD). OBJECTIVE: This study documents the North American Contact Dermatitis Group (NACDG) patch-testing results from January 1, 2011, to December 31, 2012. METHODS: At 12 centers in North America, patients were tested in a standardized manner with a series of 70 allergens. Data were manually verified and entered into a central database. Descriptive frequencies were calculated, and trends analyzed using χ statistics. RESULTS: Four thousand two hundred thirty-eight patients were tested; of these, 2705 patients (63.8%) had at least 1 positive reaction, and 2029 (48.0%) were ultimately determined to have a primary diagnosis of ACD. Four hundred eight patients (9.6%) had occupationally related skin disease. There were 7532 positive allergic reactions. As compared with previous reporting periods (2009-2010 and 2000-2010), positive reaction rates statistically increased for 6 allergens: methylchloroisothiazolinone/methylisothiazolinone (5.0%; risk ratios [RRs]: 2.01 [1.60-2.52], 1.87 [1.61-2.18]), lanolin alcohol (4.6%; RRs 1.83 [1.45-2.30], 2.10 [1.79-2.47]), cinnamic aldehyde (3.9%; 1.69 [1.32-2.15], 1.53 [1.28-1.82]), glutaral (1.5%; 1.67 [1.13-2.48], 1.31 [1.00-1.71]), paraben mix (1.4%; 1.77 [1.16-2.69], 1.44 [1.09-1.92]), and fragrance mix I (12.1%; RRs 1.42 [1.25-1.61], 1.24 [1.14-1.36]). Compared with the previous decade, positivity rates for all formaldehyde-releasing preservatives significantly decreased (formaldehyde 6.6%; RR, 0.82 [0.73, 0.93]; quaternium-15 6.4% RR 0.75 [0.66, 0.85]; diazolidinyl urea 2.1%; RR, 0.67 [0.54, 0.84]; imidazolidinyl urea 1.6%, 0.60 [0.47, 0.77]; bronopol 1.6%; RR, 0.60 [0.46, 0.77]; DMDM hydantoin 1.6%; RR, 0.59 [0.54, 0.84]). Approximately a quarter of patients had at least 1 relevant allergic reaction to a non-NACDG allergen. In addition, approximately one-fourth to one-third of reactions detected by NACDG allergens would have been hypothetically missed by T.R.U.E. TEST (SmartPractice Denmark, Hillerød, Denmark). CONCLUSIONS: These data document the beginning of the epidemic of sensitivity to methylisothiazolinones in North America, which has been well documented in Europe. Patch testing with allergens beyond a standard screening tray is necessary for complete evaluation of occupational and nonoccupational ACD.