Anthony Goon - Academia.edu (original) (raw)
Papers by Anthony Goon
British Journal of Dermatology, 2000
Many patients with psoriasis are known to suffer from itch. However, the data available regarding... more Many patients with psoriasis are known to suffer from itch. However, the data available regarding itch and its characteristics in psoriasis are sparse. To examine the prevalence of pruritus and various related clinical characteristics in 101 patients with extensive psoriasis. A structured questionnaire was used. Generalized pruritus was a feature of psoriasis in 84% of the patients. In 77% of these it appeared on a daily basis. It involved all areas of the body, had prolonged duration and appeared mainly in the evening and at night. The pruritus significantly affected quality of life. Important daily factors that were found to exacerbate the itch were ambient heat (81%), skin dryness (80%), sweating (65%) and stress (55%). Important factors that were found to ameliorate itch were sleep (57%) and cold showers (55%). The pruritus was found to be unresponsive to most available antipruritics, including phototherapy. Itch intensity as reflected by a visual analogue scale did not correlate with Psoriasis Area and Severity Index scores; however, a highly significant correlation was obtained between the affective descriptors and itch intensity in the worst itch states (r = 0.6, P < 0.001). Pruritus is a common feature of psoriasis and affects quality of life.
Annals of the Academy of Medicine, Singapore
Leg ulcers are a chronic condition affecting the older population. In Singapore, the use of topic... more Leg ulcers are a chronic condition affecting the older population. In Singapore, the use of topical traditional Chinese medicaments (TTCM) is common amongst those older than 65 years of age. We study the role of TTCM as contact sensitisers in patients with chronic venous leg ulcers and its impact in the clinical management of these patients. Patients with chronic leg ulcers attending the Wound and Ulcer Clinic at the National Skin Centre (NSC) between October 2005 and April 2006 were patch-tested to the NSC TTCM series. They were also patch-tested for other allergens from the NSC Standard Series, Medicament Series, Steroid Series and wound dressings. A total of 44 patients were patch-tested. Seventeen of the 44 (38.7%) patients were using or had used at least 1 TTCM. Seven patients (15.9%) had at least 1 positive patch test (PT) reading to TTCM, giving a sensitisation rate of 41% (7 of 17). A significantly high proportion of the patients, 94.1% (16 of 17) with a positive history of ...
Contact Dermatitis, 2008
ABSTRACT We will analyze incidence of allergy to nickel, cobalt, chromate and gold for 2001–3 and... more ABSTRACT We will analyze incidence of allergy to nickel, cobalt, chromate and gold for 2001–3 and compare this with previous studies in the same centre (1992–92, 1986–90, 1984–85) to look for changing trends in metal allergy in Singapore. We have noted that the prevalence of nickel and chromate allergy in our centre is rising again.
British Journal of Dermatology, 2002
Although pruritus is a predominant symptom of chronic idiopathic urticaria (CIU) its clinical cha... more Although pruritus is a predominant symptom of chronic idiopathic urticaria (CIU) its clinical characteristics have not been explored. To characterize the clinical pattern and sensory and affective dimensions of the itch experience, utilizing a comprehensive itch questionnaire. A structured questionnaire based on the McGill pain questionnaire was used in 100 patients suffering from CIU randomly recruited from a tertiary referral centre. All 100 patients recruited with CIU completed the questionnaire. In 68 patients pruritus appeared on a daily basis. Most patients experienced their pruritus at night and in the evening (n = 83), and 62 reported difficulty in falling asleep. Pruritus involved all body areas, but mostly the arms (n = 86), back (n = 78) and legs (n = 75). Accompanying symptoms were a sensation of heat in 45 patients and sweating in 15. Most patients (n = 98) were prescribed antihistamines (mainly sedating), of whom 34 experienced long-term relief. The sensation of itch was reported to be stinging (n = 27), tickling (n = 25) and burning (n = 23). Seventy-six patients found their pruritus bothersome, 66 annoying and 14 complained of depression. The itch intensity at its peak was more than double that felt after a mosquito bite. The worst itch scores of those who felt depressed were significantly higher than of those who did not (P = 0.018). There was a positive correlation between the sensory and affective scores during worst itch (P < 0.001). This study describes the itch experienced in CIU, highlighting sensory and affective dimensions. The itch questionnaire was found to be a valuable tool for evaluating pruritus in CIU and its unique features.
International journal of dermatology, 2002
Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical cha... more Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical characteristics have not been explored. To characterize the clinical pattern and sensory and affective dimensions of the itch experience utilizing a comprehensive itch questionnaire. A structured itch questionnaire based on the McGill pain questionnaire was given to 102 Chinese patients with known atopic dermatitis. There were 100 patients with atopic dermatitis who fully filled the questionnaire. In 87% of the patients pruritus appeared on a daily basis. It had a prolonged duration (mean duration 10.7 7.3 years). It involved all body areas mostly in the lower limbs (83%), flexures (76%), upper limbs (71%) and neck (65%). Itch intensity during its peak was nearly twice higher than the itch of a mosquito bite. Itching was most frequent at night (65%), and 84% of patients reported of difficulty falling asleep. Daily life activities which increased the severity of itch were sweat in 96%, dryne...
Journal of the American Academy of Dermatology, 2001
Contact Dermatitis, 2008
No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates... more No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates in patch tested populations have been published. To determine the prevalence of acrylate/methacrylate allergy in all patients tested to the baseline patch test series. Five acrylate/methacrylate allergens (2-hydroxyethyl methacrylate, methyl methacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, and 2-hydroxypropyl acrylate) were included in the baseline series for at least 2 years in Malmö and Singapore. Thirty-eight patients in total had reacted to acrylate/methacrylate allergens in the baseline series during the study period in both populations. In Malmö, there were 26 (1.4%) patients with positive patch tests to acrylate/methacrylate allergens, 14 of whom had relevant reactions. In Singapore, there were 12 (1.0%) patients with positive patch tests to acrylate/methacrylate allergens, but only 1 had relevant reactions. If we had not added acrylate/methacrylate allergens to the baseline series, we would not have patch tested 13/26 (50%) of the positive reactors in Malmö and 11/12 (92%) of the positive reactors in Singapore. The overall proportion of missed positive reactors would have been 24/38 (63%). The prevalence of acrylate/methacrylate allergy in our patch tested dermatitis populations is 1.4% in Malmö and 1.0% in Singapore.
Contact Dermatitis, 2006
Contact allergy to dental allergens is a well-studied subject, more so among dental professionals... more Contact allergy to dental allergens is a well-studied subject, more so among dental professionals than dental patients. 1632 subjects had been patch tested to either the dental patient series or dental personnel series at the department of Occupational and Environmental Dermatology, Malmö, Sweden. Positive patch tests to (meth)acrylate allergens were seen in 2.3% (30/1322) of the dental patients and 5.8% (18/310) of the dental personnel. The most common allergen for both groups was 2-hydroxyethyl methacrylate (2-HEMA), followed by ethyleneglycol dimethacrylate (EGDMA), triethyleneglycol dimethacrylate, and methyl methacrylate. 47 (29 dental patients and 18 dental personnel) out of these 48 had positive patch tests to 2-HEMA. All 30 subjects who had a positive reaction to EGDMA had a simultaneous positive reaction to 2-HEMA. One dental patient reacted only to 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA). From our data, screening for (meth)acrylate contact allergy with 2-HEMA alone would have picked up 96.7% (29/30) of our (meth)acrylate-allergic dental patients and 100% (18/18) of our (meth)acrylate-allergic dental personnel. The addition of bis-GMA in dental patients would increase the pick-up rate to 100%.
Contact Dermatitis, 2012
Although acrylate/methacrylate allergy has been frequently reported, until now patch testing with... more Although acrylate/methacrylate allergy has been frequently reported, until now patch testing with this group of allergens has been unwieldy, requiring the application of large supplementary series in most centres. To formulate and evaluate two mixes of acrylate/methacrylate allergens in three centres (Malmö, Singapore, and Leuven). All patients tested with the baseline series during the study period were also patch tested with the mixes. Mix 1 consisted of: triethyleneglycol diacrylate (TREGDA) 0.1% wt/wt, 2-hydroxyethyl methacrylate (2-HEMA) 1.0% wt/wt and ethyleneglycol dimethacrylate 1.0% wt/wt in petrolatum. Mix 2 consisted of: TREGDA 0.1% wt/wt and 2-HEMA 2.0% wt/wt in pet. The separate components of the two mixes were also tested simultaneously. There were 25 (5 males; 20 females) positive reactions to mix 1 with 16 in Malmö, 8 in Singapore, and 1 in Leuven. Positive reactions to mix 2 were seen only in Malmö, in 8 female patients. Thus, the positive reaction rate for mix 1 was 8.3% overall (Malmö 7.7%, Singapore 18.6%, and Leuven 2.1%), and that for mix 2 was 2.7% overall (Malmö 3.8%, Singapore 0%, and Leuven 0%). Of the 16 positive reactions to mix 1 in Malmö, only 4 were considered to be true allergic reactions, as the component allergen testing gave totally negative results in 12/16. For mix 2, only 3/8 positive reactions were considered to be true allergic reactions, as the component testing was negative in 5/8. Many doubtful (10-20%) and positive but non-allergic reactions were recorded, leading to early termination of the study. Although this was an unsuccessful attempt to formulate an acrylate/methacrylate mix, our experience will be useful for those embarking on future attempts to do this.
Dermatitis
Contact allergy to acrylates and methacrylates is not uncommon. The allergy is confirmed by patch... more Contact allergy to acrylates and methacrylates is not uncommon. The allergy is confirmed by patch-testing patients with commercial patch-test preparations. To investigate acrylate and methacrylate allergens used for patch testing in nine different dermatology departments from Europe, America, Asia, and Australia. The acrylate and methacrylate (methyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, ethylene glycol dimethacrylate, and triethylene glycol diacrylate) allergen samples were analyzed with high-performance liquid chromatography to measure the allergen content. Variation in measured versus stated concentrations was seen in these samples. The ratio of measured to stated concentrations ranged from 0.11 to 1.1. Only 22 (63%) of 35 samples were within the arbitrary acceptable limits of 80 to 120% of the stated concentrations. The results may have implications for individual diagnosis and prevention and when test results from various centers are compared.
International journal of dermatology, 2002
Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical cha... more Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical characteristics have not been explored. To characterize the clinical pattern and sensory and affective dimensions of the itch experience utilizing a comprehensive itch questionnaire. A structured itch questionnaire based on the McGill pain questionnaire was given to 102 Chinese patients with known atopic dermatitis. There were 100 patients with atopic dermatitis who fully filled the questionnaire. In 87% of the patients pruritus appeared on a daily basis. It had a prolonged duration (mean duration 10.7 7.3 years). It involved all body areas mostly in the lower limbs (83%), flexures (76%), upper limbs (71%) and neck (65%). Itch intensity during its peak was nearly twice higher than the itch of a mosquito bite. Itching was most frequent at night (65%), and 84% of patients reported of difficulty falling asleep. Daily life activities which increased the severity of itch were sweat in 96%, dryne...
Dermatitis (formerly American Journal of Contact Dermatitis), 2004
Although chlorhexidine is a widely used substance, allergic contact dermatitis from chlorhexidine... more Although chlorhexidine is a widely used substance, allergic contact dermatitis from chlorhexidine has rarely been reported. Our objective was to study all cases of allergic contact dermatitis from chlorhexidine that were seen at St John&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Institute of Dermatology from January 1983 to June 2002. The case records of all patients with positive patch-test reactions to chlorhexidine during the study period were retrieved. The clinical presentation, strength, and relevance of the positive patch-test results as well as possible sources of exposure were studied. There were five cases of allergic contact dermatitis from chlorhexidine during the study period; three of these patients had positive patch-test reactions to chlorhexidine that were of current relevance. The possible sources of exposure included Hibisol, Hibiscrub, a chlorhexidine spray, and peri- and postoperative antiseptic solutions. We concluded that allergic contact dermatitis from chlorhexidine is rare. However, when it occurs, it may cause a severe dermatitis reaction.
Contact Dermatitis, 2010
Not all skin contact reactions present as eczema or dermatitis. There are several distinct nonecz... more Not all skin contact reactions present as eczema or dermatitis. There are several distinct noneczematous contact reactions which are more commonly seen. The mechanisms of these reactions are not clearly elucidated yet. It is very useful to clinicians to be able to identify these dermatoses as contact reactions so that they may be confirmed with patch testing and other unnecessary
Dermatitis : contact, atopic, occupational, drug
Preservatives are indispensable agents used to prevent bacterial and fungal contamination of cosm... more Preservatives are indispensable agents used to prevent bacterial and fungal contamination of cosmetics, personal care products, domestic preparations, and industrial products. We evaluated patch-test data at the National Skin Centre, Singapore, from 2006 to 2011 to identify the trends in preservative contact allergies. All patients with suspected contact dermatitis were patch tested to 4 preservatives within the modified European standard series. Patients were also tested with 7 preservatives from our special series if clinically indicated. Three thousand one hundred seventy-seven patients were tested to preservatives in the standard series. Sensitization frequencies were all greater than 1%: parabens (2.58%), methylchloroisothiazolinone/methylisothiazolinone (1.75%), quaternium 15 (1.43%), and methyldibromoglutaronitrile (1.2%). There was no change in trends in sensitization frequencies from 2006 to 2011, with no increase in sensitization frequency to methylchloroisothiazolinone/me...
The Journal of dermatology, 2012
Photodermatology, Photoimmunology & Photomedicine, 2013
Occupational Medicine, 2009
The restaurant industry is a rapidly growing sector in Singapore and workers in this industry are... more The restaurant industry is a rapidly growing sector in Singapore and workers in this industry are trained in culinary skills but not on recognition of safety and health hazards and their control measures. Anecdotal clinical evidence has suggested an increased prevalence of occupational dermatoses among restaurant workers. To determine the prevalence and risk factors for contact dermatitis and burns among restaurant, catering and fast-food outlet (FFO) staff. Workers were interviewed and then clinical examination and patch and/or prick tests were conducted in selected individuals. In total, 335 of 457 workers (73% response) were interviewed and 65 (19%) had occupational dermatitis or burns and were examined. Of these, contact dermatitis was the commonest diagnosis, with a 12-month period prevalence of 10% (35 workers) and 3-month period prevalence of 8% (26 workers). All 35 workers had irritant contact dermatitis (ICD) and there were no cases of allergic contact dermatitis. The adjusted prevalence rate ratios of risk factors for ICD were 2.78 (95% CI 1.36-5.72) for frequent hand washing &amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;20 times per day, 3.87 (95% CI 1.89-7.93) for atopy and 2.57 (95% CI 1.21-5.47) for contact with squid. The 3-month period prevalence for burns was 6% (20 workers). Ten workers had other occupational dermatoses such as work-related calluses, paronychia, heat rash and allergic contact urticaria to prawn and lobster. ICD and burns are common occupational skin disorders among restaurant, catering and FFO workers.
British Journal of Dermatology, 2000
Many patients with psoriasis are known to suffer from itch. However, the data available regarding... more Many patients with psoriasis are known to suffer from itch. However, the data available regarding itch and its characteristics in psoriasis are sparse. To examine the prevalence of pruritus and various related clinical characteristics in 101 patients with extensive psoriasis. A structured questionnaire was used. Generalized pruritus was a feature of psoriasis in 84% of the patients. In 77% of these it appeared on a daily basis. It involved all areas of the body, had prolonged duration and appeared mainly in the evening and at night. The pruritus significantly affected quality of life. Important daily factors that were found to exacerbate the itch were ambient heat (81%), skin dryness (80%), sweating (65%) and stress (55%). Important factors that were found to ameliorate itch were sleep (57%) and cold showers (55%). The pruritus was found to be unresponsive to most available antipruritics, including phototherapy. Itch intensity as reflected by a visual analogue scale did not correlate with Psoriasis Area and Severity Index scores; however, a highly significant correlation was obtained between the affective descriptors and itch intensity in the worst itch states (r = 0.6, P &amp;lt; 0.001). Pruritus is a common feature of psoriasis and affects quality of life.
Annals of the Academy of Medicine, Singapore
Leg ulcers are a chronic condition affecting the older population. In Singapore, the use of topic... more Leg ulcers are a chronic condition affecting the older population. In Singapore, the use of topical traditional Chinese medicaments (TTCM) is common amongst those older than 65 years of age. We study the role of TTCM as contact sensitisers in patients with chronic venous leg ulcers and its impact in the clinical management of these patients. Patients with chronic leg ulcers attending the Wound and Ulcer Clinic at the National Skin Centre (NSC) between October 2005 and April 2006 were patch-tested to the NSC TTCM series. They were also patch-tested for other allergens from the NSC Standard Series, Medicament Series, Steroid Series and wound dressings. A total of 44 patients were patch-tested. Seventeen of the 44 (38.7%) patients were using or had used at least 1 TTCM. Seven patients (15.9%) had at least 1 positive patch test (PT) reading to TTCM, giving a sensitisation rate of 41% (7 of 17). A significantly high proportion of the patients, 94.1% (16 of 17) with a positive history of ...
Contact Dermatitis, 2008
ABSTRACT We will analyze incidence of allergy to nickel, cobalt, chromate and gold for 2001–3 and... more ABSTRACT We will analyze incidence of allergy to nickel, cobalt, chromate and gold for 2001–3 and compare this with previous studies in the same centre (1992–92, 1986–90, 1984–85) to look for changing trends in metal allergy in Singapore. We have noted that the prevalence of nickel and chromate allergy in our centre is rising again.
British Journal of Dermatology, 2002
Although pruritus is a predominant symptom of chronic idiopathic urticaria (CIU) its clinical cha... more Although pruritus is a predominant symptom of chronic idiopathic urticaria (CIU) its clinical characteristics have not been explored. To characterize the clinical pattern and sensory and affective dimensions of the itch experience, utilizing a comprehensive itch questionnaire. A structured questionnaire based on the McGill pain questionnaire was used in 100 patients suffering from CIU randomly recruited from a tertiary referral centre. All 100 patients recruited with CIU completed the questionnaire. In 68 patients pruritus appeared on a daily basis. Most patients experienced their pruritus at night and in the evening (n = 83), and 62 reported difficulty in falling asleep. Pruritus involved all body areas, but mostly the arms (n = 86), back (n = 78) and legs (n = 75). Accompanying symptoms were a sensation of heat in 45 patients and sweating in 15. Most patients (n = 98) were prescribed antihistamines (mainly sedating), of whom 34 experienced long-term relief. The sensation of itch was reported to be stinging (n = 27), tickling (n = 25) and burning (n = 23). Seventy-six patients found their pruritus bothersome, 66 annoying and 14 complained of depression. The itch intensity at its peak was more than double that felt after a mosquito bite. The worst itch scores of those who felt depressed were significantly higher than of those who did not (P = 0.018). There was a positive correlation between the sensory and affective scores during worst itch (P < 0.001). This study describes the itch experienced in CIU, highlighting sensory and affective dimensions. The itch questionnaire was found to be a valuable tool for evaluating pruritus in CIU and its unique features.
International journal of dermatology, 2002
Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical cha... more Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical characteristics have not been explored. To characterize the clinical pattern and sensory and affective dimensions of the itch experience utilizing a comprehensive itch questionnaire. A structured itch questionnaire based on the McGill pain questionnaire was given to 102 Chinese patients with known atopic dermatitis. There were 100 patients with atopic dermatitis who fully filled the questionnaire. In 87% of the patients pruritus appeared on a daily basis. It had a prolonged duration (mean duration 10.7 7.3 years). It involved all body areas mostly in the lower limbs (83%), flexures (76%), upper limbs (71%) and neck (65%). Itch intensity during its peak was nearly twice higher than the itch of a mosquito bite. Itching was most frequent at night (65%), and 84% of patients reported of difficulty falling asleep. Daily life activities which increased the severity of itch were sweat in 96%, dryne...
Journal of the American Academy of Dermatology, 2001
Contact Dermatitis, 2008
No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates... more No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates in patch tested populations have been published. To determine the prevalence of acrylate/methacrylate allergy in all patients tested to the baseline patch test series. Five acrylate/methacrylate allergens (2-hydroxyethyl methacrylate, methyl methacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, and 2-hydroxypropyl acrylate) were included in the baseline series for at least 2 years in Malmö and Singapore. Thirty-eight patients in total had reacted to acrylate/methacrylate allergens in the baseline series during the study period in both populations. In Malmö, there were 26 (1.4%) patients with positive patch tests to acrylate/methacrylate allergens, 14 of whom had relevant reactions. In Singapore, there were 12 (1.0%) patients with positive patch tests to acrylate/methacrylate allergens, but only 1 had relevant reactions. If we had not added acrylate/methacrylate allergens to the baseline series, we would not have patch tested 13/26 (50%) of the positive reactors in Malmö and 11/12 (92%) of the positive reactors in Singapore. The overall proportion of missed positive reactors would have been 24/38 (63%). The prevalence of acrylate/methacrylate allergy in our patch tested dermatitis populations is 1.4% in Malmö and 1.0% in Singapore.
Contact Dermatitis, 2006
Contact allergy to dental allergens is a well-studied subject, more so among dental professionals... more Contact allergy to dental allergens is a well-studied subject, more so among dental professionals than dental patients. 1632 subjects had been patch tested to either the dental patient series or dental personnel series at the department of Occupational and Environmental Dermatology, Malmö, Sweden. Positive patch tests to (meth)acrylate allergens were seen in 2.3% (30/1322) of the dental patients and 5.8% (18/310) of the dental personnel. The most common allergen for both groups was 2-hydroxyethyl methacrylate (2-HEMA), followed by ethyleneglycol dimethacrylate (EGDMA), triethyleneglycol dimethacrylate, and methyl methacrylate. 47 (29 dental patients and 18 dental personnel) out of these 48 had positive patch tests to 2-HEMA. All 30 subjects who had a positive reaction to EGDMA had a simultaneous positive reaction to 2-HEMA. One dental patient reacted only to 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA). From our data, screening for (meth)acrylate contact allergy with 2-HEMA alone would have picked up 96.7% (29/30) of our (meth)acrylate-allergic dental patients and 100% (18/18) of our (meth)acrylate-allergic dental personnel. The addition of bis-GMA in dental patients would increase the pick-up rate to 100%.
Contact Dermatitis, 2012
Although acrylate/methacrylate allergy has been frequently reported, until now patch testing with... more Although acrylate/methacrylate allergy has been frequently reported, until now patch testing with this group of allergens has been unwieldy, requiring the application of large supplementary series in most centres. To formulate and evaluate two mixes of acrylate/methacrylate allergens in three centres (Malmö, Singapore, and Leuven). All patients tested with the baseline series during the study period were also patch tested with the mixes. Mix 1 consisted of: triethyleneglycol diacrylate (TREGDA) 0.1% wt/wt, 2-hydroxyethyl methacrylate (2-HEMA) 1.0% wt/wt and ethyleneglycol dimethacrylate 1.0% wt/wt in petrolatum. Mix 2 consisted of: TREGDA 0.1% wt/wt and 2-HEMA 2.0% wt/wt in pet. The separate components of the two mixes were also tested simultaneously. There were 25 (5 males; 20 females) positive reactions to mix 1 with 16 in Malmö, 8 in Singapore, and 1 in Leuven. Positive reactions to mix 2 were seen only in Malmö, in 8 female patients. Thus, the positive reaction rate for mix 1 was 8.3% overall (Malmö 7.7%, Singapore 18.6%, and Leuven 2.1%), and that for mix 2 was 2.7% overall (Malmö 3.8%, Singapore 0%, and Leuven 0%). Of the 16 positive reactions to mix 1 in Malmö, only 4 were considered to be true allergic reactions, as the component allergen testing gave totally negative results in 12/16. For mix 2, only 3/8 positive reactions were considered to be true allergic reactions, as the component testing was negative in 5/8. Many doubtful (10-20%) and positive but non-allergic reactions were recorded, leading to early termination of the study. Although this was an unsuccessful attempt to formulate an acrylate/methacrylate mix, our experience will be useful for those embarking on future attempts to do this.
Dermatitis
Contact allergy to acrylates and methacrylates is not uncommon. The allergy is confirmed by patch... more Contact allergy to acrylates and methacrylates is not uncommon. The allergy is confirmed by patch-testing patients with commercial patch-test preparations. To investigate acrylate and methacrylate allergens used for patch testing in nine different dermatology departments from Europe, America, Asia, and Australia. The acrylate and methacrylate (methyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, ethylene glycol dimethacrylate, and triethylene glycol diacrylate) allergen samples were analyzed with high-performance liquid chromatography to measure the allergen content. Variation in measured versus stated concentrations was seen in these samples. The ratio of measured to stated concentrations ranged from 0.11 to 1.1. Only 22 (63%) of 35 samples were within the arbitrary acceptable limits of 80 to 120% of the stated concentrations. The results may have implications for individual diagnosis and prevention and when test results from various centers are compared.
International journal of dermatology, 2002
Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical cha... more Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical characteristics have not been explored. To characterize the clinical pattern and sensory and affective dimensions of the itch experience utilizing a comprehensive itch questionnaire. A structured itch questionnaire based on the McGill pain questionnaire was given to 102 Chinese patients with known atopic dermatitis. There were 100 patients with atopic dermatitis who fully filled the questionnaire. In 87% of the patients pruritus appeared on a daily basis. It had a prolonged duration (mean duration 10.7 7.3 years). It involved all body areas mostly in the lower limbs (83%), flexures (76%), upper limbs (71%) and neck (65%). Itch intensity during its peak was nearly twice higher than the itch of a mosquito bite. Itching was most frequent at night (65%), and 84% of patients reported of difficulty falling asleep. Daily life activities which increased the severity of itch were sweat in 96%, dryne...
Dermatitis (formerly American Journal of Contact Dermatitis), 2004
Although chlorhexidine is a widely used substance, allergic contact dermatitis from chlorhexidine... more Although chlorhexidine is a widely used substance, allergic contact dermatitis from chlorhexidine has rarely been reported. Our objective was to study all cases of allergic contact dermatitis from chlorhexidine that were seen at St John&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s Institute of Dermatology from January 1983 to June 2002. The case records of all patients with positive patch-test reactions to chlorhexidine during the study period were retrieved. The clinical presentation, strength, and relevance of the positive patch-test results as well as possible sources of exposure were studied. There were five cases of allergic contact dermatitis from chlorhexidine during the study period; three of these patients had positive patch-test reactions to chlorhexidine that were of current relevance. The possible sources of exposure included Hibisol, Hibiscrub, a chlorhexidine spray, and peri- and postoperative antiseptic solutions. We concluded that allergic contact dermatitis from chlorhexidine is rare. However, when it occurs, it may cause a severe dermatitis reaction.
Contact Dermatitis, 2010
Not all skin contact reactions present as eczema or dermatitis. There are several distinct nonecz... more Not all skin contact reactions present as eczema or dermatitis. There are several distinct noneczematous contact reactions which are more commonly seen. The mechanisms of these reactions are not clearly elucidated yet. It is very useful to clinicians to be able to identify these dermatoses as contact reactions so that they may be confirmed with patch testing and other unnecessary
Dermatitis : contact, atopic, occupational, drug
Preservatives are indispensable agents used to prevent bacterial and fungal contamination of cosm... more Preservatives are indispensable agents used to prevent bacterial and fungal contamination of cosmetics, personal care products, domestic preparations, and industrial products. We evaluated patch-test data at the National Skin Centre, Singapore, from 2006 to 2011 to identify the trends in preservative contact allergies. All patients with suspected contact dermatitis were patch tested to 4 preservatives within the modified European standard series. Patients were also tested with 7 preservatives from our special series if clinically indicated. Three thousand one hundred seventy-seven patients were tested to preservatives in the standard series. Sensitization frequencies were all greater than 1%: parabens (2.58%), methylchloroisothiazolinone/methylisothiazolinone (1.75%), quaternium 15 (1.43%), and methyldibromoglutaronitrile (1.2%). There was no change in trends in sensitization frequencies from 2006 to 2011, with no increase in sensitization frequency to methylchloroisothiazolinone/me...
The Journal of dermatology, 2012
Photodermatology, Photoimmunology & Photomedicine, 2013
Occupational Medicine, 2009
The restaurant industry is a rapidly growing sector in Singapore and workers in this industry are... more The restaurant industry is a rapidly growing sector in Singapore and workers in this industry are trained in culinary skills but not on recognition of safety and health hazards and their control measures. Anecdotal clinical evidence has suggested an increased prevalence of occupational dermatoses among restaurant workers. To determine the prevalence and risk factors for contact dermatitis and burns among restaurant, catering and fast-food outlet (FFO) staff. Workers were interviewed and then clinical examination and patch and/or prick tests were conducted in selected individuals. In total, 335 of 457 workers (73% response) were interviewed and 65 (19%) had occupational dermatitis or burns and were examined. Of these, contact dermatitis was the commonest diagnosis, with a 12-month period prevalence of 10% (35 workers) and 3-month period prevalence of 8% (26 workers). All 35 workers had irritant contact dermatitis (ICD) and there were no cases of allergic contact dermatitis. The adjusted prevalence rate ratios of risk factors for ICD were 2.78 (95% CI 1.36-5.72) for frequent hand washing &amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;20 times per day, 3.87 (95% CI 1.89-7.93) for atopy and 2.57 (95% CI 1.21-5.47) for contact with squid. The 3-month period prevalence for burns was 6% (20 workers). Ten workers had other occupational dermatoses such as work-related calluses, paronychia, heat rash and allergic contact urticaria to prawn and lobster. ICD and burns are common occupational skin disorders among restaurant, catering and FFO workers.