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ABSTRACT: Photopatch testing is important for diagnosing photoallergic contact dermatitis. We aimed to evaluate the use of photopatch test at the National Skin Centre, Singapore.
All patients who had photopatch tests done between 2007 and 2011 at the National Skin Centre were included.
Twenty-two patients were included. The mean age was 40.2. Female : male ratio was 3.4. The ethnic groups were Chinese (68%), Malay (4%), Indian (14%) and others (14%). Ten out of 22 patients (45.5%) had a positive photopatch test. There were 20 positive photopatch test reactions found in these 10 patients, and all 20 positive reactions were of current relevance. The frequencies of the positive photopatch test reactions were 2-hydroxy-4-methoxybenzophenone (oxybenzone) (n = 6), 2-hydroxymethoxymethylbenzophenone (mexenone) (n = 3), 2-ethylhexyl-4-dimethylaminobenzoate (n = 1), ketoprofen gel (n = 1) and the patient's own product (n = 9).
Our study suggests that sunscreen is the most common photoallergen to date as opposed to musk ambrette, which was the most common photoallergen in our earlier study in 1991-1993. This finding is similar to the recent European Multicentre Photopatch Test Study.
Photodermatology Photoimmunology and Photomedicine 06/2013; 29(3):116-20. · 1.30 Impact Factor
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ABSTRACT: 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 TTCM usage had at least 1 positive PT reading compared to those without a history of TTCM usage, 45.8% (11 of 24).
TTCM play an important role as contact sensitisers in our patients with chronic venous leg ulcers and may be a significant factor in non- or poor-healing leg ulcers. In such patients, a history of TTCM usage should be sought for and patch testing should include the commonly used TTCM where relevant.
Annals of the Academy of Medicine, Singapore 12/2007; 36(11):942-6. · 1.25 Impact Factor
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ABSTRACT: Contact sensitization rates are high in patients with chronic venous leg ulcers. Allergic contact dermatitis poses a significant hindrance to the healing of the wounds. There are no published studies examining the rate of contact sensitization in Asian patients. Our objective was to determine the rate of contact sensitization in patients with chronic venous leg ulcer in Singapore and the variation in the common allergens based on local practices in comparison with Western countries. 44 patients were patch tested to the National Skin Centre standard series, steroid series, medicaments, topical Chinese medicaments, and to modern wound dressings used. The overall rate of contact sensitization was 61.4%. The common allergen groups were topical antibiotics (18.2%) and topical traditional Chinese medicaments (TTCM) (15.9%). Individually, colophony (11.3%), Saw Hong Choon skin ointment (Kam Bo Med, Hong Kong, Hong Kong) (11.3%), Balsam of Peru (9.1%), and povidone iodine (9.1%) were among the most frequent allergens. The sensitization rate among users of TTCM was notably high (41%). A high rate of contact sensitization was found in our study, similar to previous reports from the West. TTCM play a major role as possible allergens in our patients. In Asian patients, a history of its usage should be elicited, and patch testing should include the commonly used TTCM where possible.
Contact Dermatitis 03/2007; 56(2):94-8. · 3.51 Impact Factor
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ABSTRACT: Severe acute respiratory syndrome (SARS) was first recognized in February 2003. It is the first severe and readily transmissible new disease to emerge in the 21st century. Healthcare workers in affected countries were exposed to the regular use of personal protective equipment (PPE) such as the N95 mask, gloves, and gowns. Our aim was to study the prevalence of adverse skin reactions to PPE among healthcare workers in Singapore during the SARS outbreak. Healthcare staff in the National Skin Centre and Tan Tock Seng Hospital were surveyed using questionnaires. Of those asked to participate, 322 (94.7%) agreed. 14.3% of the respondents were doctors, 73.0% nurses, and 12.7% other ancillary staff. Mean age of respondents was 32.4 years, with the majority being women (85.7%) and Chinese (53.7%). 109 (35.5%) of the 307 staff who used masks regularly reported acne (59.6%), facial itch (51.4%), and rash (35.8%) from N95 mask use. 64 (21.4%) of the 299 who used gloves regularly reported dry skin (73.4%), itch (56.3%), and rash (37.5%). The use of PPE is associated with high rates of adverse skin reactions. There is a need to find suitable alternatives for affected staff and to encourage awareness among staff of the role of dermatologists in their care.
Contact Dermatitis 12/2006; 55(5):291-4. · 3.51 Impact Factor
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ABSTRACT: Few reports have documented allergic hypersensitivity reactions after barium gastrointestinal studies. Of these, the barium suspension, its additives or intravenous glucagon given for bowel relaxation has been implicated as possible allergens. We report a patient with delayed hypersensitivity reaction after barium enema and discuss the reasons supporting glucagon as the possible allergen.
A 74-year-old Chinese woman presented with pruritic rashes, 1 day after a barium enema. Intravenous glucagon (GlucaGen, Novo Nordisk, Denmark) was administered during the barium enema. Physical examination revealed palpable purpuric rashes on the legs with erythematous papules and plaques on the arms and trunk. Skin biopsy demonstrated superficial perivascular infiltrates of lymphocytes and eosinophils, consistent with a drug eruption.
The rashes resolved with antihistamines and topical corticosteroids.
This report highlights the potential of glucagon to cause hypersensitivity reactions. Awareness of this entity is important for the prevention and recognition of complications during barium gastrointestinal studies.
Annals of the Academy of Medicine, Singapore 05/2006; 35(4):279-81. · 1.25 Impact Factor
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ABSTRACT: To compare laser Doppler perfusion imaging (LDPI) measurements in experimentally induced allergic contact reactions and irritant contact reactions. The degree of correlation between visual scores and LDPI measurements was also studied.
Fifteen patients with known contact allergy to nickel or fragrance were patch tested with nickel sulfate 5% pet., fragrance mix 8% pet., sodium lauryl sulfate (SLS) 0.5% pet., SLS 1.0% pet. and two empty control chambers. Visual readings and LDPI measurements were taken at 0, 48 and 96 h.
There was a positive correlation between visual scores and LDPI measurement in the nickel sulfate and fragrance mix patch test sites. However, no correlation between visual scores and LDPI measurements was seen in the SLS 0.5% and SLS 1.0% patch test sites. There was no significant difference (P=0.125) in LDPI measurements between contact-allergic reactions and contact-irritant reactions.
LDPI correlates with visual scoring in contact-allergic reactions, but not in irritant reactions. LDPI is not useful in distinguishing between allergic and irritant reactions.
Skin Research and Technology 03/2004; 10(1):64-6. · 1.71 Impact Factor
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Contact Dermatitis 08/2003; 49(1):48-9. · 3.51 Impact Factor
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Contact Dermatitis 10/2002; 47(3):166. · 3.51 Impact Factor
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ABSTRACT: Background Dermatomyositis has been reported to be associated with malignancies in 15%–34% of patients in Western countries, but in as many as two-thirds of patients in Singapore. The aim of this study was to determine whether a diagnostic measure could be helpful in the diagnosis of a malignancy in patients with dermatomyositis.Methods This is a retrospective study on 38 adult patients with dermatomyositis that were seen over a 6-year period from 1989 to 1994.Results All the patients presented with cutaneous features that suggest the clinical diagnosis of dermatomyositis; however, not all cases show all the key features of the disease. Of the studied patients, 86.8% were noted to have photosensitivity as a key cutaneous presentation. Thirty (78.9%) of our patients were above the age of 40 years, and 12 (31.6%) of these were found to have an associated malignancy. Nasopharyngeal carcinoma was the most commonly associated malignancy (38.4%) in our study population.Conclusions In our study population, otorhinolaryngologic screening is an essential investigation for the evaluation of dermatomyositis in association with malignancy.
International journal of dermatology 11/1997; 36(12):904 - 907. · 1.18 Impact Factor
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ABSTRACT: Singapore has a resident population of 3 000 000 and a workforce of 1 780 000. Most are employed in manufacturing, services and commerce (245 000). From 1996 to 1998, 3472 cases were notified to the Ministry of Manpower and confirmed as occupational diseases. Noise-induced hearing loss accounted for 82% of cases, while only 11% of cases were industrial dermatitis. Occupational allergic contact dermatitis was not common, comprising approximately one third of the 369 cases of industrial dermatitis that were notified. However, we believe that the majority of cases are not notified to the authorities. The main occupational contact allergens were chromates, nickel, rubber chemicals, cutting fluids and resins. Most affected workers were from the construction, electronics and metalworking industries. Case series of occupational dermatoses among electronics and metal workers have been published. Of the cases of occupational dermatoses among electronics workers seen at a tertiary dermatological centre, 41% of 149 had allergic contact dermatitis (ACD). The commonest allergens were nickel, resins and rubber chemicals. In another case series of 252 metalworkers seen at the same dermatological centre, 23% suffered from ACD. The common allergens were metals and cutting fluids. Besides the common causes of ACD, unusual allergens have also been described. One example is ACD to grasses, which is seen mainly among military personnel. Population studies have been conducted in several industries. A survey of 2567 electronics workers revealed a 2% point prevalence of ACD. Of the occupationally relevant cases, 46 were nickel sensitive, 7 reacted to colophony, and 1 case to epoxy resin. A study of 272 prefabrication construction workers showed a 14% prevalence rate of occupational dermatitis. Of the 38 cases, 42% were ACD to chromates and rubber chemicals. Occupational ACD in Singapore is not as uncommon as the reported statistics suggest. Population-based reports, which overcome the problem of under-notification, show that the prevalence is variable in different industries.
Science of The Total Environment.
