Acta Derm Venereol 2006; 86: 509–514 INVESTIGATIVE REPORT Allergic Contact Dermatitis Due to β-blockers in Eye Drops: a Retrospective Analysis of Multicentre Surveillance Data 1993– 2004 Uta JAPPE1, Wolfgang UTER2, Cristiane A. MENEZES de PÁDUA2, Rudolf A. HERBST3 and Axel SCHNUCH4 1Department of Dermatology, University of Heidelberg, 2Department of Medical Informatics, Biometry and Epidemiology, University of Erlangen, 3Department of Dermatology and Allergology, Klinikum Bayreuth GmbH, and 4Information Network of Departments of Dermatology (IVDK), University of Goettingen, Germany Topically applied ophthalmic drugs are a potential cause β-blockers) (1, 2). Contact allergy after topical admini- of allergic contact dermatitis of the periorbital region. stration of anti-glaucoma agents is apparently rare. The objectives of this study were to assess the frequency β-blockers (timolol, metipranolol, levobunol, betaxolol, and spectrum of contact allergy to topically applied and carteolol (Fig. 1) are used in cases of pathologically β-blocker containing eye drops. Data of the Information increased intraocular pressure and manifest glaucoma, Network of Departments of Dermatology (IVDK) collect- because of their efficacy and relatively low incidence of ed between 1993 and 2004 was analysed. Out of 112,430 systemic side-effects, such as hypotension, bradycardia patch-tested patients, 332 had been tested with their and bronchospasm (3, 4). own topical anti-glaucoma eye drops containing dif- However, local adverse events in terms of skin reac- ferent β-blockers because of suspected allergic contact tions also occur. Initially, it may be difficult to distin- dermatitis. The frequency of positive test reactions was guish between irritant contact dermatitis and allergic related to exposure intensity, as estimated by annual pre- scription rates in Germany. A total of 43/332 (12.95%) showed at least one positive patch test reaction. Positive reactions were observed to products containing timolol (n = 21), metipranolol (n = 13) and levobunolol (n = 11) without conceivable cross-reactivity. Whereas exposure to β-blocker-containing eye drops remained stable over the years, as estimated by the prescription rates, a slight, non-significant increase in positive patch-reactions to these substances was noted. This is the first systematic analysis of a large set of data on patients’ own β-blocker topical medications, the results indicating that contact allergy should be considered as important, if rare, adverse event caused by this family of drugs. Key words: allergic contact dermatitis; β-blocker; cross-reaction; eye drops; eyelid dermatitis; glaucoma; own medicaments. (Accepted June 8, 2006.) Acta Derm Venereol 2006; 86: 509–514. Uta Jappe, MD, MSc, Department of Dermatology, Uni- versity of Heidelberg, Voßstrasse 2, DE-69115 Heidelberg, Germany. E-mail: [email protected] Cutaneous reactions to ophthalmic drugs are usually mild and transitory. Causative agents include preserva- tives (e.g. thimerosal or benzalkonium chloride) and a large number of pharmaceutical compounds (antibio- tics, sympathomimetics, sympatholytics, cholinergics, cholinolytics, antiallergics, antivirals, local anaesthetics, local antihistamines, corticosteroids, antiphlogistics, and Fig. 1. Chemical structure of various β-blockers. © 2006 Acta Dermato-Venereologica. ISSN 0001-5555 Acta Derm Venereol 86 DOI: 10.2340/00015555-0162 510 U. Jappe et al. contact dermatitis. Allergic contact conjunctivitis and noted that, according to current guidelines (22) all tests were dermatitis from eye drops have previously been found read until D3. In several instances, but not routinely, readings were continued until D7. to be due to preservatives, especially benzalkonium While standardized patch test series have routinely been applied chloride, sodium EDTA and thimerosal (5, 6). However, in virtually all the patients considered, this analysis focuses on according to recent reports in the literature, the culprit patients’ own medications (Table I) and those ingredients of agents have changed over the years: the pharmacologi- relevant eye drop brands available as standardized, commercial cally active ingredients now seem to play the major role allergens (Table II). as contact sensitizers, whereas preservatives usually remain negative in diagnostic allergy testing (7–10). Data handling and statistics Moreover, allergic reactions to ophthalmic drugs are Data analysis was done using the statistical program system SAS probably more frequent than described in the literature (version 8.2, SAS Institute, Cary, NC, USA) (20). Important so far. Diagnostic efforts to identify an alternative agent demographic characteristics of a patch test population are summed-up by the MOAHLFA index (23). tolerated by the patient allergic to one β-blocker, led to Proportions (frequency of sensitization to β-blocker-contain- the observation of delayed-type cross-reactivity between ing eye drops) were supplemented with an exact 95% confidence levobunol and carteolol, levobunol and timolol, levo- interval (CI) based on the binomial distribution (24). The degree bunol and befunolol, befunolol and metipranolol, meti- of concordance between positive reactions to β-blockers (e.g. pranolol and 1-penbutolol, and befunolol and carteolol due to immunological cross-reactivity) or other patient’s own eye drops used as anti-glaucoma drugs was quantified using in several cases, the development of cross-reactions so Cohen’s kappa. far not being predictable (11–19). Furthermore, it is a question if previous exposure to the “cross-reacting” Share of the market analysis compound (and concomitant sensitization) was exclud- Information on ophthalmic specialties containing β-blockers on ed in every case of assumed cross-reaction. Thus, in the the German market from 1993 to 2004 was retrieved from a list present analysis, we aimed to describe the frequency and of drug specialties (25). The prescription rate of the major brand pattern of (cross-) sensitization to β-blocker eye drops specialties commercialized in Germany in the same period in among patients on topical treatment for glaucoma, who terms of “defined daily doses” (DDD) was determined based were patch-tested with their eye drops in the depart- on another reference (26). ments of IVDK (Information Network of Departments of Dermatology) (www.ivdk.org) – between 1993 and RESULTS 2004 because of suspected allergic contact dermatitis to these products. Important demographic characteristics of the subgroup of β-blocker positively patch-tested ophthalmic patients according to the MOAHLFA-index are: Males (n=16, MATERIALS AND METHODS 37.2%), Occupational dermatosis (n=0), Atopic Derma- titis (n=2, 4.7%), Hand dermatitis (n=0), Leg dermatitis Study population (n=0), Face dermatitis (n=34, 79.1%), >=40 years of From 1993 to 2004, 112,430 patients altogether were patch- Age (n=41, 95.3%) – note that information on site or tested in the departments of dermatology comprising the IVDK. The IVDK is a multicentre surveillance system on contact occupational causation may have referred to concurrent allergies, with more than 40 departments of dermatology in contact dermatitis due to other causes. Germany, Austria and Switzerland participating. Patch test In 59.4% of the patients, allergic contact dermatitis results and history of all patients tested are recorded electroni- to ophthalmics was “strongly suspected” prior to patch cally in a standardized way, and transferred regularly to the testing, based on the clinical picture at presentation IVDK data centre at the University of Goettingen (20). A total of 332/112,430 patients were on topical treatment with anti- and on past history. In contrast, in 32.1% of the cases, glaucoma drugs, suspected to have contact dermatitis to the eye patch-testing was performed only to rule out contact drops and thus patch-tested with these eye drops. Data analysis allergy. In 28 patients (8.5%), other reasons for patch- is based on these 332 patients. testing were given. Patch test procedure Table I. Patch tests results of 332 patients tested with their own Patch tests were performed according to the international β-blocker containing eye drops in the Information Network of guidelines of the ICDRG (21) further extended by the German Departments of Dermatology centres from 1993 to 2004 Contact Dermatitis Research Group (22). Commercially available patch test substances were obtained from Hermal β-blocker Patients Positive 95% CI (Reinbek, FRG); however, up to now, β-blocking agents are n n (%) not commercially available as pure test substance to the best Betaxolol 25 0 0.0–11.3 of our knowledge. Patch test exposure time was 2 days for Carteolol 13 0 0.0–20.6 250 of the 332 patients and one day for the remainder, according Levobunolol 84 11 (13.1) 6.7–22.2 to the routine test procedure in the respective centre. Results Metipranolol 86 13 (13.3) 7.2–21.4 presented on β-blockers are based on readings between D3 Timolol 189 21 (11.1) 7.0–16.5 and D7 after the application of patch test material. It should be CI, confidence interval. Acta Derm Venereol 86 Contact allergy to β-blockers in eye drops 511 Table II. Results of patch testing four common adjuvants of eye drops in patients positive for β-blockers (Group 1, n = 43) and patients tested with their own β-blockers 1993–2004 in the Information Network of Departments of Dermatology (readings 3 days after application of patch test) β-blocker positive (n = 43) β-blocker negative (n = 289) No. of patch