Anthony Teik-Jin Goon

The prevalence and clinical characteristics of pruritus among patients with extensive psoriasis

Background Many patients with psoriasis are known to suffer from itch. However, the data available regarding itch and its characteristics in psoriasis are sparse. Objectives To examine the prevalence of pruritus and various related clinical characteristics in 101 patients with extensive psoriasis. Methods A structured questionnaire was used. Results 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). Conclusions Pruritus is a common feature of psoriasis and affects quality of life.

Clinical characteristics of pruritus in chronic idiopathic urticaria

Summary Background Although pruritus is a predominant symptom of chronic idiopathic urticaria (CIU) its clinical characteristics have not been explored.

Epidemiology of occupational skin disease in Singapore 1989–1998

This is an epidemiologic study of occupational skin disease in Singapore. All patients diagnosed with occupational dermatoses in the National Skin Centre, Singapore, over the 10‐year period 1989–1998 were studied retrospectively. Irritant contact dermatitis was found to be more common than allergic contact dermatitis. The major sources of occupational dermatitis in Singapore were the metal/engineering, building/construction, electrical/electronics and transport industries. The main irritants were detergents/wet work, solvent and oil/grease. The main allergens were chromate, rubber chemicals and nickel. We concluded that the main sources of occupational skin disease and main allergens in Singapore had remained the same compared to a similar study of occupational skin diseases in 1984–85. Weak irritants are still the predominant causes of occupational irritant contact dermatitis, though the main irritants have changed compared to the previous study, where cutting fluids, cement and solvent were the most common irritants.

Contact allergy to acrylates/methacrylates in the acrylate and nail acrylics series in southern Sweden: simultaneous positive patch test reaction patterns and possible screening allergens.

In a recent study we showed that all our dental personnel/patients were detected with 2‐hydroxyethyl methacrylate (2‐HEMA) and 2,2‐bis[4‐(2‐hydroxy‐3‐methacryloxypropoxy)phenyl]propane (bis‐GMA). We studied 90 patients tested to the acrylate and nail acrylics series at our department over a 10 year period to see whether screening allergens could be found. Patch testing with an acrylate and nail acrylics series was performed. Among the 10 acrylate/methacrylate‐allergic occupational dermatitis patients tested to the acrylate series, the most common allergens were triethyleneglycol diacrylate (TREGDA, 8), diethyleneglycol diacrylate (5), and 1,4‐butanediol diacrylate (BUDA, 5). All 10 of these patients would have been picked up by a short screening series combining TREGDA, 2‐hydroxypropyl methacrylate (2‐HPMA), and BUDA or 1,6‐hexanediol diacrylate (HDDA). Among the 14 acrylate/methacrylate‐allergic nail patients, the most common allergens were ethylene glycol dimethacrylate (EGDMA, 11), 2‐HEMA, (9), and triethyleneglycol dimethacrylate (9). Screening for 3 allergens i.e. 2‐HEMA plus EGDMA plus TREGDA, would have detected all 14 nail patients. A short screening series combining 2‐HEMA, EGDMA, TREGDA, 2‐HPMA, bis‐GMA, and BUDA or HDDA would have picked up all our past study patients (dental, industrial, and nail) with suspected allergy to acrylate/methacrylate allergens.

A randomized double‐blind controlled trial to compare a triclosan‐containing emollient with vehicle for the treatment of atopic dermatitis

The use of topical antiseptics in the treatment of atopic dermatitis (AD) has previously been explored. However, no triclosan‐containing leave‐on emollient has been evaluated previously, to our knowledge. The aims of this study were to assess the safety and efficacy of an emollient containing triclosan compared with the emollient alone (vehicle) for the treatment of AD. Eligible patients with mild to moderate AD were randomized to receive either the study cream or vehicle. All patients also received a low‐potency corticosteroid cream to use during the treatment phase of the study if necessary. Patients were assessed for severity according to the SCORing Atopic Dermatitis (SCORAD) Index, amount of corticosteroid used, patient assessment of cream, and adverse events (AEs). In total, 60 patients received either the study cream or vehicle, and an intention‐to‐treat analysis was performed. At day 14, there was a significant decrease in SCORAD from baseline for the study cream compared with vehicle (P < 0.05). At day 27, although there was an improved mean reduction from baseline, this was no longer significant (P > 0.05). Only four patients had mild treatment‐related AEs. The mean total amount of topical steroid applied by the patients using the study was significantly lower than that used by controls (P = 0.40). Triclosan‐containing leave‐on emollient was safe and highly acceptable to patients. However, the overall benefit on day 27 was not significant. Nevertheless, the amount of topical steroid used by patients was significantly less with the study cream than with the vehicle, thus further studies are needed to confirm its steroid‐sparing effect.

Screening for acrylate/methacrylate allergy in the baseline series: our experience in Sweden and Singapore.

Background:  No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates in patch tested populations have been published.

Oral tolerance to contact allergens: A common occurrence? A review

Experimental and clinical oral tolerance to contact allergens has been reported sporadically, most notably in respect of nickel, and is generally assumed to be an uncommon phenomenon. There has recently been increased understanding of the immunological mechanisms inducing and maintaining oral tolerance. There are several contact allergens, including fragrance, antioxidant, and preservative chemicals, to which subjects are exposed through both cutaneous and oral routes. We examine the possibility that oral tolerance to contact allergens may be more common than previously thought. Animal models of oral tolerance to contact allergens indicate that cutaneous exposure to small, subsensitizing doses of contact allergens might negate any subsequent attempts to induce tolerance by oral administration. Extrapolating these observations to common human practises raises the possibility that application of contact allergens (fragrances, preservatives and antioxidants) in consumer products used by children could prevent or inhibit the later acquisition of specific tolerance resulting from ‘natural’ dietary exposure after weaning. Existing data on formaldehyde may conflict with this theory, though this could be explained by allergen specificity. We propose that further work in this area is needed.

Contact sensitization in patients with chronic venous leg ulcers in Singapore.

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.

Barrier repair in chronic plaque‐type psoriasis

Purpose: To investigate barrier repair after mild trauma in lesional skin of psoriasis patients with chronic plaque‐type disease and to compare this with non‐involved psoriatic skin and normal controls.

Variation in allergen content over time of acrylates⁄ methacrylates in patch test preparations

Background  Acrylates/methacrylates are volatile substances. There might be a gradual decrease in acrylate/methacrylate allergen content over time in patch test preparations but this has not yet been documented.