A retrospective analysis of contact allergy to lanolin

BACKGROUND: Lanolin is often stated to be an important sensitizer but some of the available literature is based on the analysis of high-risk patients. OBJECTIVES: To analyse the frequency of contact allergy to lanolin (wool alcohols) in a central London teaching hospital patch-test population. METHODS: Review of 24,449 patients recorded on our database during 1982--96 who were tested with a standard series containing 30% wool alcohols. RESULTS: The mean annual rate of sensitivity to this allergen was 1.7%. The wool alcohols-allergic group contained a higher proportion of females (P < 0.05), and the mean age of both males and females (48.4 and 49.2 years) was higher than that of non-wool alcohols-allergic patients (41.4 and 35.9 years; P < 0.0005). There was no difference in atopic eczema status between these groups. The highest prevalence of allergy to wool alcohols was among patients with lower leg dermatitis (6.0%; 95% confidence interval, CI 4.46--7.54), followed by those with anogenital dermatitis (3.23%; 95% CI 1.81--4.65). There was an unexplained decline in the rate of positive patch tests to Amerchol L-101. However, some patients who reacted to this were negative with wool alcohols, so it may be a useful additional test reagent. The mean rates of allergy to Eucerin (0.65% per annum) and 50% hydrogenated lanolin in petrolatum (1% per annum) were low, and we no longer use these as test reagents. CONCLUSIONS: This study illustrates that lanolin sensitization has remained at a relatively low and constant rate even in a high-risk population (i.e. patients with recent or active eczema).     

The relevance of chlorhexidine contact allergy

Background. Chlorhexidine is used for disinfection of skin and mucosae in medicine and dentistry. Prolonged exposure may lead to contact sensitization and allergic contact dermatitis or stomatitis. Objectives. The purpose of this study was to analyse the sources of chlorhexidine exposure and sensitization, and to obtain data on the prevalence of sensitization and chlorhexidine‐related contact allergy. Patients and methods. From 1999, patch testing was performed with chlorhexidine digluconate (0.5% aq.) on 7610 general dermatology patients with suspected contact allergy at the Turku University Hospital Dermatology Department. The medical records were reviewed concerning the patients' exposure to chlorhexidine. Results. A positive patch reaction to chlorhexidine was seen in 36 patients (0.47%). Current dermatitis or stomatitis caused by chlorhexidine‐containing topical medicaments was seen in 5 patients. Chlorhexidine sensitization contributed to the current dermatitis in 11 patients. A history of earlier exposure to chlorhexidine‐containing products was recalled by only 16 sensitized patients, whereas no exposure was revealed in 4 cases. Conclusions. Chlorhexidine‐containing corticosteroid creams, skin disinfectants and oral hygiene products are principal sources of chlorhexidine contact sensitization. Exposure to chlorhexidine in cosmetics may lead to delayed improvement of eczema in sensitized patients, emphasizing the importance of identifying the potential cosmetic sources.     

Cheilitis caused by contact allergy to cocamidopropyl betaine in '2-in-1 toothpaste and mouthwash'

A 10-year-old girl presented with a 2-year history of severe cheilitis. Despite cessation of any lip-licking behaviour her symptoms continued to worsen, with only minimum relief from therapeutic measures. Patch testing proved strongly positive to cocamidopropyl betaine, which was noted to be present in the patient's '2-in-1 toothpaste and mouthwash'. Her cheilitis settled after avoidance of this product. Cocamidopropyl betaine, a surfactant, is a common allergen in hairdressers; however, this case highlights the importance of excluding a contact allergy to this product in patients with intractable cheilitis.     

Cheilitis caused by contact allergy to anethole in spearmint flavoured toothpaste

A 63-year-old woman presented with a 6-year history of persistent cheilitis. Minimal improvement was achieved with therapeutic measures. Patch testing was positive to anethole, a flavouring used in her toothpaste. Her cheilitis resolved after cessation of the flavoured toothpaste. This case demonstrates the importance of considering contact allergy to toothpaste flavours in patients with cheilitis.     

Exposure to metallic gold in patients with contact allergy to gold sodium thiosulfate

Gold allergy is common, with approximately 10% of patients patch tested because of eczematous disease being positive to gold sodium thiosulfate (GSTS). However, clinical relevance seems to be rare. The aim of this prospective double-blind study was to demonstrate the effects of exposure to metallic gold, in this case earrings, in gold-positive patients. 60 female patients with pierced earlobes test-positive to GSTS were included in the study. The patients were randomized into 2 groups, 30 patients receiving earrings with a surface layer consisting of 24-carat gold and 30 patients earrings with a surface layer of titanium nitride, virtually indistinguishable from gold. The patients wore the earrings for 8 weeks. During the study, any dermatitis on the earlobes, as well as on other body sites, was registered. The skin reactions observed were weak but, in total, 17 of the 60 patients had a skin reaction (local or remote) during the study, 12 of whom had received gold earrings and 5 titanium (p<0.05). 11 patients had a reaction on the earlobes, 7 of whom had received gold earrings and 4 titanium (NS). With these facts it is hard to exclude that exposure to gold jewelry can be clinically relevant in persons hypersensitive to gold.     

Dose-time relationships for elicitation of contact allergy to para-phenylenediamine

Skin-sensitizing chemicals exhibit dose-response relationships for the elicitation of contact dermatitis. Previously, considerable work has been carried out in which the elicitation of allergic skin reaction has been examined as a function of the applied concentration. However, the relationship between exposure time, dose and response has not been explored in any depth. The present work has extended our initial assessment of the relationship between both exposure time and concentration for para-phenylenediamine (PPD) in a group of 19 PPD-allergic volunteers. The results clearly demonstrate that a relationship exists between both exposure time and concentration. Positive responses to PPD were directly proportional to exposure time: at 5 min 16% responded; at 15 min, 38%; at 30 min, 50%; and at 120 min, 69%. A similar direct relationship was found between concentration of PPD and response: after 120 min, 22% of patients had responded to 0.01%, and 69% to 1% PPD. All exposures for 1 and 2 min were negative. Subsequent evaluation using repeated 5 min open application testing demonstrated a cumulative effect, as after 8 days 39% of the panel reacted, more than double the number that reacted to a single occluded 5-min treatment. It was noted that there was marked subject variability in exposure time and dose required to elicit an allergic response. These results are of relevance for the general interpretation of patch test data, especially with regard to risk assessment.     

Allergic contact dermatitis to plant extracts in patients with cosmetic dermatitis

Cosmetic contact allergy is commonly seen in patients undergoing patch testing, with fragrance one of the most frequently implicated ingredients. Many cosmetics contain plant extracts either as a fragrance or for medicinal properties. With a vogue for natural products there is an increase in their use. We have performed a prospective study over a 2-year period looking at the prevalence of contact allergy to plants in patients diagnosed with cosmetic dermatitis. In addition, we have performed a review of the products of two popular cosmetic companies, examining product labelling and the prevalence of use of plant extracts. We suggest that patients allergic to fragrance be advised to avoid plant extracts, which are separately labelled, in their personal care products.     

Occupational contact allergy to (meth)acrylates

Among 13,833 patients suspected of contact dermatitis examined during the years 1978-1999, occupational contact allergy to (meth)acrylates was diagnosed in 31 patients. The 3 most common sensitizers were ethyleneglycol dimethacrylate (17 positive patch tests), 2-hydroxyethyl methacrylate (14) and triethyleneglycol dimethacrylate (6). The aim of this report was to assess the different occupations and industries responsible for occupational sensitization to (meth)acrylates. 14 of the 31 patients work in the dental sector, either as a dentist or as a student of dental technology, where (meth)acrylate-containing dental prostheses and dental composites are mainly responsible for allergy to (meth)acrylates. An increasing trend in dermatological problems related to the expansion of the use of (meth)acrylates is clearly reflected in the patient population of our dermatology department.     

The cause of the Chinese sofa/chair dermatitis epidemic is likely to be contact allergy to dimethylfumarate, a novel potent contact sensitizer

Background  A small epidemic of severe contact dermatitis cases related to newly acquired sofas and chairs has surpassed the news threshold in Finland and the U.K.
Objectives  To study affected patients and to identify the cause.
Methods  Five patients with contact dermatitis related to a newly purchased chair or sofa were studied. Furniture samples were analysed by gas chromatography–mass spectrometry. Compounds were identified using a mass spectrum library and measured semiquantitatively. Patch tests were performed with commercial standard allergens, furniture upholstery and chemicals found in the analysis.
Results  Patch tests with commercial allergens did not solve the problem. Up to 470 μg kg⁻¹ of dimethylfumarate was found in chairs. The patients showed strong positive patch test reactions to upholstery fabric samples and to dimethylfumarate, down to a level of 1 p.p.m. in the most severe case.
Conclusions  The cause of the Chinese sofa/chair dermatitis epidemic is likely to be contact allergy to dimethylfumarate, a novel potent contact sensitizer.     

Fragrance contact allergy in Iran

Background Fragrances are considered as one of the most common causes of allergic contact dermatitis. About 1–4% of the general population suffer from fragrance contact allergy (FCA). Objectives To determine the frequency of FCA and its clinical relevance in a sample of Iranian patients with history of contact and/or atopic dermatitis from January 2004 to December 2008. Methods Standardized patch testing with 28‐allergen screening series recommended by the German Contact Dermatitis Research Group and European Standard Series was used at six dermatological clinics in Iran. Fragrance allergens comprised of fragrance mix I (FM I), Myroxylon pereirae (MP; balsam of Peru), Lyral^®, turpentine and FM II. Results Fragrance contact allergy was detected in 7.2% of the patients. The frequency of positive reactions to FM I, MP and FM II were 3.7% (41/1105), 2.8% (32/1135) and 1.1% (3/267) respectively. 82.4% of the reactions to fragrance allergens were clinically relevant. The most common involved areas were hands (68.4%) and face (35.4%). Fragrance allergy predominantly affected women aged more than 40 years (P = 0.008). Positive reaction to more than two allergens was significantly higher in FCA patients compared with other contact dermatitis patients (P < 0.0001), and FM I, nickel and MP were the most frequent allergens in these patients. Conclusions Despite less frequency of FCA in comparison with some European countries, its clinical relevance in Iranian patients seems to be high. It mostly affects the hands and the face predominantly in women aged more than 40 years.     

The prognosis of occupational contact dermatitis in 2004

The prognosis of occupational contact dermatitis (OCD) takes into account the extent of healing, effect on quality of life and employment, and financial costs for both the individual and the wider community. We reviewed 15 studies published between 1958 and 2002, reporting the complete clearance of dermatitis (range of 18-72%). 9 of the 15 studies reported a clearance rate of between 18 and 40%. Improvement was reported as an outcome in 3 studies between 1991 and 2002 (range of 70-84%). A number of common variables were identified as of possible influence. These include age, sex, atopy, patient knowledge, disease aetiology, duration of symptoms and job change; clinical, financial and social issues are also described. All of these factors need to be considered when managing a patient with OCD. Improved patient knowledge and early diagnosis may be associated with improved prognosis, whereas job change does not make a significant difference. Some patients will develop persistent post-occupational dermatitis, which has important implications for prognosis and workers' compensation. Only a small proportion of eligible patients receive workers' compensation, even though financially supported healing time soon after diagnosis may result in an improved prognosis.