Haptens, Proteins, and Atopic Dermatitis. / Haptenos, proteínas y dermatitis atópica.

Atopic dermatitis is a chronic inflammatory disease that is multifactorial in nature. Allergic contact dermatitis and protein contact dermatitis are allergic conditions that may occur in the context of atopic dermatitis and be the cause of exacerbations. Although the prevalence of allergic contact dermatitis is similar in atopic patients and the general population, these 2 conditions are frequently associated because atopic inflammation disrupts the skin barrier. Skin tests are therefore recommended in atopic individuals. Dupilumab could be useful for treating allergic contact dermatitis if it is mediated by type 2 helper T cells but could exacerbate inflammation if mediated by TH1 cells: further study is needed before conclusions can be drawn. Although the mechanism by which exposure to environmental proteins exacerbates atopic dermatitis remains under discussion, such exacerbations are routinely seen in clinical practice. Prick testing is recommended in symptomatic atopic dermatitis. When prick-test findings are positive, patients should be advised to avoid the culprit substances.

Pruritus in Dermatology: Part 2 - Diseases and Their Treatment. / Prurito en dermatología. Enfermedades y su tratamiento. Parte 2.

Pruritus is the main symptom of many dermatologic and systemic diseases. Atopic dermatitis, psoriasis, contact dermatitis, urticaria, lichen simplex chronicus, mycosis fungoides, scars, autoimmune diseases, kidney or liver diseases among others are all associated with itch that may require different approaches to management. Although antihistamines seem to be the first line of therapy, in reality their role is limited to urticaria and drug-induced reactions. In fact, the pathophysiologic mechanisms of each of the conditions covered in this review will differ. Recent years have seen the emergence of new drugs whose efficacy and safety profiles are very attractive for the management of pruritus in clinical practice. Clearly we are at a critical moment in dermatology, in which we have the chance to be more ambitious in our goals when treating patients with pruritus.

Contact Allergy in Patients with Rosacea. / Sensibilización alérgica de contacto en pacientes con rosácea.

BACKGROUND AND OBJECTIVE: Rosacea is a chronic acneiform skin disorder in which impaired skin barrier function can lead to sensitization to allergens. We aimed to analyze contact allergies in our patients with rosacea. MATERIAL AND METHODS: Retrospective cohort study of all patients who underwent patch testing in our skin allergy clinic between May 1991 and May 2019. RESULTS: A total of 200 patients with rosacea were referred to our clinic for patch testing during the study period; they represented 2.1% of all patch tested patients in the period. Eighty-one percent were women (mean age, 44.7years). At least 1positive patch test was recorded for 46.5%; 15% were of current relevance. The most frequent positive reaction was to nickel (26%), followed by cobalt chloride (6.5%), isothiazolinones (6%), p-phenylenediamine (5.5%), fragrance mixII (5%), and thimerosal (3.5%). The most common currently relevant patch test reactions were to isothiazolinones in 10 of the 200 patients (5%); to phenylenediamine, fragrance mixII, and toluensulfonamide formaldehyde resin in 4 patients (2%) each; and to tixocortol and fragrance mixI in 2 patients (1%) each. The allergen groups most often implicated were metals (of current relevance in 12.6%) and drugs (of current relevance in 25.8%). Preservatives and fragrances were the next most common allergen groups, and 70.8% and 43.7% of the positive reactions in these groups, respectively, were of current relevance. Cosmetics were the most frequent source of sensitization, followed by topical medications - notably corticosteroids and antifungal agents. CONCLUSIONS: We emphasize the high prevalence of allergic contact dermatitis in patients with rosacea, a finding which supports patch testing, especially if eruptions worsen when these patients use cosmetics and topical medications.

Epidemiological, Clinical, and Allergy Profile of Patients With Atopic Dermatitis and Hand Eczema: Evaluation of the Spanish Contact Dermatitis Registry (REIDAC). / Perfil epidemiológico, clínico, y alérgico en pacientes con dermatitis atópica y dermatitis de las manos. Evaluación del Registro Español de Dermatitis de Contacto (REIDAC).

BACKGROUND: Hand eczema is common in patients with atopic dermatitis (AD), but few studies have described the characteristics of these patients in large, representative populations from different geographic regions and occupational settings. OBJECTIVE: To describe the epidemiological, clinical, and allergy profile of patients with hand eczema who underwent patch testing and compare patients with and without AD. METHODS: Analysis of data from the Spanish Contact Dermatitis Registry, a multicenter registry of patients who undergo patch testing in Spain. RESULTS: We included 1466 patients with hand eczema who were patch tested between January 2018 and June 2020. Those with AD were younger and had had symptoms for longer before testing. They were also more likely to have been exposed to occupational triggers (38% vs 53% for patients without AD). The only profession for which significant differences were found was hairdressing. The most common allergens were nickel sulfate, methylchloroisothiazolinone/methylisothiazolinone, cobalt chloride, potassium dichromate, fragrance mixes I and II, and formaldehyde. The most common diagnoses were allergic contact dermatitis (24% vs 31% in patients with and without AD, P=.0224) and irritant contact dermatitis (18% and 35% respectively, P<.001). CONCLUSIONS: AD is common in patients with predominant hand eczema who undergo patch testing. Patients with hand eczema and AD have different clinical and epidemiological characteristics to hand eczema patients in general and their final diagnosis following patch testing is also different.

Contact Dermatitis to Allergens in the Spanish Standard Series: Patch Test Findings in the South of Gran Canaria. / Dermatitis de contacto a alérgenos de la Batería Estándar Española en población del sur de Gran Canaria.

BACKGROUND AND OBJECTIVES: Contact dermatitis is a common reason for consultation in dermatology. Sensitization levels and frequency, however, vary from one population to the next. The aim of this study was to review patch test results showing sensitization to allergens in the Spanish standard series in the Canary Islands, where a large proportion of the population works in tourism. MATERIAL AND METHODS: Retrospective, descriptive study of data from the dermatology department's contact dermatitis unit at Complejo Hospitalario Universitario Insular in Las Palmas de Gran Canaria, Spain. We studied results recorded for patients patch tested with the Spanish standard series between January 2005 and June 2018. RESULTS: Data for 1568 patients were studied; 71.6% were women, and overall rates of atopy (14.2%) and occupational dermatitis (15.8%) were low. Most patients with a positive test (65.2%) were older than 40years. The main allergens eliciting positive reactions were nickel (36.5%), methylchloroisothiazolinone/methylisothiazolinone (11.9%), methylisothiazolinone (11.8%), paraphenylenediamine (7.5%), and potassium dichromate (6.3%). CONCLUSIONS: Contact sensitization rates were higher than those reported elsewhere in Spain for most of the allergens studied. The differences were particularly notable for nickel, methylchloroisothiazolinone/methylisothiazolinone, and paraphenylenediamine.

Preservatives in Personal Hygiene and Cosmetic Products, Topical Medications, and Household Cleaners in Spain. / Conservantes en productos de higiene y cosméticos, medicamentos tópicos y productos de limpieza doméstica en España.

INTRODUCTION: Preservatives are added to cosmetic, household cleaning, and other industrial products to prevent the growth of microorganisms. Unfortunately, exposure to these substances can cause sensitization. MATERIAL AND METHODS: Between January and June 2015, we analyzed the ingredients of 2300 products commercially available in Spain to identify the frequency of a wide variety of preservatives in different product categories. We analyzed 1093 skin care and cosmetic products sold exclusively in pharmacies (dermocosmetics), 458 household cleaning and personal hygiene and cosmetic products sold in supermarkets, 636 topical medications, and 113 cosmetic products sold in a herbal shop. RESULTS: Phenoxyethanol, citric acid, sodium benzoate, and potassium sorbate were very common in all the cosmetic product categories. Parabens were present in 16.1% of dermocosmetic products, 14.45% of cosmetic products available in supermarkets, 0.88% of cosmetic products available in the herbal shop, 5.18% of topical medications, and in none of the cleaning products. Isothiazolinones were identified in 2.56% of dermocosmetic products, 18% of cosmetic products in supermarkets, 7.9% of cosmetic products in the herbal shop, 63.63% of household cleaners, and in none of the topical medications. Formaldehyde releasers were detected in 5.76% of dermocosmetic products, 6.42% of cosmetic products sold in supermarkets, 7.96% of cosmetic products sold in the herbal shop, 3.93% of topical medications, and 16.74% of household cleaners. CONCLUSIONS: Evaluation of the presence of preservatives in everyday products allows us to indirectly estimate exposure levels to each one. Measures restricting the use of the most problematic preservatives need to be strengthened.

Hipersensitivity Reactions to Corticosteroids.

Corticosteroids are widely used drugs in the clinical practice, especially by topic application in dermatology. These substances may act as allergens and produce immediate and delayed hypersensitivity reactions. Allergic contact dermatitis is the most frequent presentation of corticosteroid allergy and it should be studied by patch testing in specific units. The corticosteroids included in the Spanish standard battery are good markers but not ideal. Therefore, if those makers are positive, it is useful to apply a specific battery of corticosteroids and the drugs provided by patients. Immediate reactions are relatively rare but potentially severe, and it is important to confirm the sensitization profile and to guide the use of alternative corticosteroids, because they are often necessary in several diseases. In this article we review the main concepts regarding these two types of hypersensitivity reactions in corticosteroid allergy, as well as their approach in the clinical practice.

The Spanish standard patch test series: 2016 update by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC). / Actualización de la serie estándar española de pruebas alérgicas de contacto por el Grupo Español de Investigación en Dermatitis de Contacto y Alergia Cutánea (GEIDAC) para 2016.

The Spanish standard patch test series, as recommended by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC), has been updated for 2016. The new series replaces the 2012 version and contains the minimum set of allergens recommended for routine investigation of contact allergy in Spain from 2016 onwards. Four haptens -clioquinol, thimerosal, mercury, and primin- have been eliminated owing to a low frequency of relevant allergic reactions, while 3 new allergens -methylisothiazolinone, diazolidinyl urea, and imidazolidinyl urea- have been added. GEIDAC has also modified the recommended aqueous solution concentrations for the 2 classic, major haptens methylchloroisothiazolinone and methylisothiazolinone, which are now to be tested at 200ppm in aqueous solution, and formaldehyde, which is now to be tested in a 2% aqueous solution. Updating the Spanish standard series is one of the functions of GEIDAC, which is responsible for ensuring that the standard series is suited to the country's epidemiological profile and pattern of contact sensitization.

Corticosteroid hypersensitivity studies in a skin allergy clinic.

INTRODUCTION: Corticosteroids can cause hypersensitivity reactions, particularly delayed-type allergic reactions. A new classification system for testing hypersensitivity to corticosteroids distributes the drugs into 3 groups according to molecular structure; patients are classified according to whether they are allergic to agents in 1 or more of the groups. We aimed to describe the clinical characteristics of corticosteroid-allergic patients treated at our clinic and apply the new classification system to them; we also compared these patients' characteristics to those of others treated at our clinic. MATERIAL AND METHODS: Retrospective study of cases of delayed-type corticosteroid hypersensitivity treated in the skin allergy clinic of a tertiary level hospital over an 11-year period. RESULTS: We reviewed the records of 2857 patients, finding 33 with at least one positive patch test result showing corticosteroid hypersensitivity. Atopic dermatitis and hand involvement were less common in our corticosteroid-allergic patients. All were allergic to a group 1 corticosteroid (most often, budesonide, the culprit in 87.9%). Testing with a specific corticosteroid series revealed that 14 (42.4%) were also allergic to corticosteroids in group 2 and/or group 3. None were allergic exclusively to group 2 or group 3 agents. Twenty-one patients were exposed to a corticosteroid cream from a group their patch test results indicated allergy to; 13 of them (61.9%) did not develop a hypersensitivity reaction. CONCLUSIONS: The Spanish standard series only contains group 1 corticosteroids. In the interest of improving allergy management, we recommend testing with a specific corticosteroid series and a patient's own creams whenever patch testing with a standard series reveals a hypersensitivity reaction to corticosteroids.

Update on allergic contact dermatitis due to methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone.

The combination of methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) is widely used as a preservative in cosmetics, household, and industrial products. Furthermore, MI at a concentration of 100 ppm has been permitted in cosmetic products since 2005. Recently, a considerable increase in cases of contact dermatitis to both MCI and MI have been noted, and this warrants closer monitoring by relevant authorities and, probably, stricter legislation. In fact, MI at a test concentration of 2000 ppm was recently included in the European baseline patch test series. The clinical manifestations of allergy to MCI/MI and MI are highly variable and diagnosis is often missed. In the standard patch test series of the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC), MCI/MI is tested at 100 ppm, but at this concentration, up to 50% of cases might go undetected. Furthermore, our data indicate that MCI/MI at 200 ppm would make it possible to diagnose more cases of contact allergy to MI. To improve the diagnosis of contact allergy to MCI/MI and MI, we believe that the test concentration of MCI/MI should be increased to 200 ppm in the GEIDAC standard series and that MI should be added in the GEIDAC standard series.

Postsurgical contact dermatitis due to povidone iodine: a diagnostic dilemma.

We present 7 cases of postsurgical contact dermatitis due to povidone iodine. The diagnosis was based on the clinical manifestations, the history of exposure, the site of the lesions, and the results of patch tests. This type of dermatitis can develop in the area of surgery or at distant sites exposed to povidone iodine during the surgical intervention. Patch tests with 10% povidone iodine in petrolatum were positive in all patients. Based on the results of the same tests in a control group, we recommend the use of petrolatum rather than water as the vehicle for the diagnosis of this form of contact dermatitis. Repeated open application tests with a commercially available solution of povidone iodine were negative. We conclude that the presence of the solution under occlusion during surgery is necessary both for the symptoms to develop and for the diagnosis to be made. This condition may be underdiagnosed.

Acute skin lesions after surgical procedures: a clinical approach.

In the hospital setting, dermatologists are often required to evaluate inflammatory skin lesions arising during surgical procedures performed in other departments. These lesions can be of physical or chemical origin. Povidone iodine is the most common reported cause of such lesions. If this antiseptic solution remains in contact with the skin in liquid form for a long period of time, it can give rise to serious irritant contact dermatitis in dependent or occluded areas. Less common causes of skin lesions after surgery include allergic contact dermatitis and burns under the dispersive electrode of the electrosurgical device. Most skin lesions that arise during surgical procedures are due to an incorrect application of antiseptic solutions. Special care must therefore be taken during the use of these solutions and, in particular, they should be allowed to dry.

Candidate Allergens for Inclusion in the Spanish Standard Series Based on Data from the Spanish Contact Dermatitis Registry. / Alérgenos candidatos para ser incluidos en la serie estándar española a partir de los datos del Registro Español de Dermatitis de Contacto.

BACKGROUND: Standard patch test series must be updated using objective data on allergen sensitization. The Spanish standard series was last updated in 2016 and the European series in 2019, and the inclusion of several emerging allergens needs to be evaluated. MATERIAL AND METHODS: We conducted a prospective, observational, multicenter study of consecutive patients from the registry of the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC) who were patch tested in 2019 and 2020 with linalool hydroperoxide, limonene hydroperoxide, 2-hydroxyethyl-methacrylate, benzisothiazolinone, octylisothiazolinone, textile dye mix (TDM), sodium metabisulfite, propolis, bronopol, Compositae mix II, diazolidinyl urea, imidazolidinyl urea, decyl glucoside, and lauryl glucoside. RESULTS: We analyzed data for 4654 patients tested with diazolidinyl urea, imidazolidinyl urea, and bronopol, and 1890 tested with the other allergens. The values for the MOAHLFA index components were 30% for male, 18% for occupational dermatitis, 15% for atopic dermatitis, 29% for hand, 6.5% for leg, 23% for face, and 68% for age > 40 years. Sensitization rates above 1% were observed for 7 allergens: linalool hydroperoxide, 2-hydroxyethyl-methacrylate, benzisothiazolinone, limonene hydroperoxide, TDM, sodium metabisulfite, and propolis. Three allergens had a current relevance rate of over 1%: linalool hydroperoxide, 2-hydroxyethyl-methacrylat, and limonene hydroperoxide. Benzisothiazolinone and TDM had a relevance rate of between 0.9% and 1%. CONCLUSIONS: Our results indicate that 7 new allergens should be considered when extending the Spanish standard patch test series. The data from our series could be helpful for guiding the next extension of the European baseline series.

Foot Eczema in a Skin Allergy Unit: Retrospective Study of 13 Years. / Eczema en los pies en una consulta de alergia cutánea: estudio retrospectivo de 13 años.

INTRODUCTION: Foot eczema is a common complaint encountered by skin allergists. OBJECTIVE: To study a series of patients with foot eczema who underwent patch testing and describe their demographic profile, diagnoses, and the main allergens involved. MATERIAL AND METHODS: Cross-sectional observational study of all patients tested with the standard Spanish patch test series at a dermatology department over a period of 13 years (2004-2016). We studied patch test results and definitive diagnoses by comparing different subgroups of patients with foot eczema. RESULTS: Of the 3,265 patients included in the study, 308 (9.4%) had foot eczema, 176 (57.9%) had foot eczema only and 132 (42.1%) had concomitant foot and hand eczema. Positive patch test results were more common in patients with foot eczema only (positivity rate of 61.5% vs. 53.4% for foot and hand eczema). In the subgroup of patients with concomitant foot and hand involvement, patients aged under 18 years had a lower rate of positive results (51.3% vs. 64.6% for patients >18 years). Potassium dichromate was the most common allergen with current relevance in all subgroups. The main diagnosis in patients with foot involvement only was allergic contact dermatitis (49.1%). In the subgroup of patients with concomitant hand and foot eczema, the main diagnoses were psoriasis in adults (33.6%) and atopic dermatitis in patients aged under 18 years (60.0%). CONCLUSION: Patch tests are a very useful diagnostic tool for patients with foot eczema with or without concomitant hand involvement.

Diagnostic Tools to Use When We Suspect an Allergic Reaction to a Tattoo: A Proposal Based on Cases at Our Hospital. / ¿Qué procedimientos diagnósticos deberíamos realizar ante una sospecha de reacción alérgica a un tatuaje? Propuesta basada en nuestra casuística.

INTRODUCTION: Tattooing has become a popular practice in western countries, particularly among younger populations. Tattoos, however, can cause complications, such as infections, allergic or foreign-body reactions, and even systemic inflammatory responses. PATIENTS AND METHODS: We conducted a retrospective study of all patients seen for tattoo-related complications at our skin allergy unit between January 2002 and December 2016. RESULTS: We studied 23 patients. Nine of these experienced early complications, all related to infection. The other 14 patients developed late reactions. Ten were diagnosed with probable allergic contact dermatitis to ink, but the suspect allergen was identified in just 3 cases and confirmed in just 1 of these. There were 2 cases of cutaneous sarcoidosis, 1 case of foreign body granuloma, and 1 case of neuropathy. CONCLUSIONS: Complications resulting from tattoos are relatively common dermatology complaints. Drawing from our experience, we propose a diagnostic algorithm designed to guide dermatologists in evaluating different reactions to tattoos and prescribing appropriate treatment.

Allergic Contact Dermatitis Due to Paraphenylenediamine: An Update. / Actualización en la dermatitis de contacto alérgica por parafenilendiamina.

Paraphenylenediamine (PPD) is an amine that is mainly used as an ingredient in hair dyes and henna tattoos. The incidence of allergic contact dermatitis to PPD is increasing, particularly in younger patients. In this article, we review the main sources of PPD and the substances with which it can interact and present a practical algorithm for diagnosing and treating suspected cases of PPD allergy.

Haptenos, proteínas y dermatitis atópica / Haptens, Proteins, and Atopic Dermatitis

La dermatitis atópica (DA) es una enfermedad inflamatoria crónica multifactorial. La dermatitis de contacto alérgica (DCA) y la dermatitis de contacto por proteínas (DCP) son patologías alérgicas que pueden ser comórbidas a la DA y ser causa de algunas de las exacerbaciones. Aunque la DCA tiene una prevalencia similar en pacientes atópicos que en la población general, debemos considerarla una comorbilidad frecuente en la DA por la disrupción de la barrera cutánea. Por ello, se recomienda la realización de pruebas epicutáneas a los pacientes atópicos. Dupilumab podría ser útil para el tratamiento de la DCA mediada por vía Th2 y exacerbar aquellas que ocurren por vía Th1, aunque se precisan más estudios para establecer conclusiones. El mecanismo por el que la exposición a proteínas ambientales produce exacerbaciones en la DA es controvertido, pero es un fenómeno habitual en la práctica clínica diaria. Se recomienda estudio mediante prick test a pacientes con clínica sugestiva y recomendar conductas evitativas ante pacientes sintomáticos y pruebas positivas (AU)

Atopic dermatitis is a chronic inflammatory disease that is multifactorial in nature. Allergic contact dermatitis and protein contact dermatitis are allergic conditions that may occur in the context of atopic dermatitis and be the cause of exacerbations. Although the prevalence of allergic contact dermatitis is similar in atopic patients and the general population, these 2 conditions are frequently associated because atopic inflammation disrupts the skin barrier. Skin tests are therefore recommended in atopic individuals. Dupilumab could be useful for treating allergic contact dermatitis if it is mediated by type 2 helper T cells but could exacerbate inflammation if mediated by TH1 cells: further study is needed before conclusions can be drawn. Although the mechanism by which exposure to environmental proteins exacerbates atopic dermatitis remains under discussion, such exacerbations are routinely seen in clinical practice. Prick testing is recommended in symptomatic atopic dermatitis. When prick-test findings are positive, patients should be advised to avoid the culprit substances (AU)

[Translated article] Haptens, Proteins, and Atopic Dermatitis / Haptenos, proteínas y dermatitis atópica

Atopic dermatitis is a chronic inflammatory disease that is multifactorial in nature. Allergic contact dermatitis and protein contact dermatitis are allergic conditions that may occur in the context of atopic dermatitis and be the cause of exacerbations. Although the prevalence of allergic contact dermatitis is similar in atopic patients and the general population, these 2 conditions are frequently associated because atopic inflammation disrupts the skin barrier. Skin tests are therefore recommended in atopic individuals. Dupilumab could be useful for treating allergic contact dermatitis if it is mediated by type 2 helper T cells but could exacerbate inflammation if mediated by TH1 cells: further study is needed before conclusions can be drawn. Although the mechanism by which exposure to environmental proteins exacerbates atopic dermatitis remains under discussion, such exacerbations are routinely seen in clinical practice. Prick testing is recommended in symptomatic atopic dermatitis. When prick-test findings are positive, patients should be advised to avoid the culprit substances (AU)

La dermatitis atópica (DA) es una enfermedad inflamatoria crónica multifactorial. La dermatitis de contacto alérgica (DCA) y la dermatitis de contacto por proteínas (DCP) son patologías alérgicas que pueden ser comórbidas a la DA y ser causa de algunas de las exacerbaciones. Aunque la DCA tiene una prevalencia similar en pacientes atópicos que en la población general, debemos considerarla una comorbilidad frecuente en la DA por la disrupción de la barrera cutánea. Por ello, se recomienda la realización de pruebas epicutáneas a los pacientes atópicos. Dupilumab podría ser útil para el tratamiento de la DCA mediada por vía Th2 y exacerbar aquellas que ocurren por vía Th1, aunque se precisan más estudios para establecer conclusiones. El mecanismo por el que la exposición a proteínas ambientales produce exacerbaciones en la DA es controvertido, pero es un fenómeno habitual en la práctica clínica diaria. Se recomienda estudio mediante prick test a pacientes con clínica sugestiva y recomendar conductas evitativas ante pacientes sintomáticos y pruebas positivas (AU)

Allergic Contact Dermatitis by Anatomical Regions: Diagnostic Clues. / Dermatitis de contacto alérgica por regiones anatómicas. Claves diagnósticas.

Allergic contact dermatitis (ACD) is a common disease in daily clinical practice, and its prevalence has increased in recent years. It is characterized clinically by varying degrees of erythema, vesiculation, flaking, and lichenification, though these signs can also be present in other eczematous diseases. Patch testing is the main diagnostic tool to confirm ACD, but its accurate interpretation requires correct correlation with the medical history (details of exposure) and physical examination. We provide a practical and instructive description of the most common clinical patters of ACD depending on the area affected. Knowledge of these patterns will not only help the clinician reach the diagnosis but will suggest possible allergens and forms of contact.