Dawn Li-Chern Lim

Parvalbumin : the major tropical fish allergen

Fish allergy is common in countries where consumption is high. Asian nations are amongst the world’s largest consumers of fish but the allergen profiles of tropical fish are unknown. This study sought to evaluate the allergenicity of four commonly consumed tropical fish, the threadfin (Polynemus indicus), Indian anchovy (Stolephorus indicus), pomfret (Pampus chinensis) and tengirri (Scomberomorus guttatus). Immunoglobulin E (IgE) cross‐reactivity with parvalbumin of cod fish (Gad c 1), the major fish allergen, was also studied. Detection of tropical fish and cod specific‐IgE was performed by UniCap assay, and skin prick tests were also carried out. The IgE‐binding components of tropical fish were identified using IgE immunoblot techniques, and cross‐reactivity with Gad c 1 was assessed by ELISA inhibition and IgE immunoblot inhibition. Clinically, nine of 10 patients studied were allergic to multiple fish. All patients exhibited detectable specific‐IgE to cod fish (10 of 10 skin prick test positive, eight of 10 UniCap assay positive) despite lack of previous exposure. The major allergen of the four tropical fish was the 12‐kDa parvalbumin. IgE cross‐reactivity of these allergens to Gad c 1 was observed to be moderate to high in the tropical fish studied. Parvalbumins are the major allergens in commonly consumed tropical fish. They are cross‐reactive with each other as well as with Gad c 1. Commercial tests for cod fish appear to be sufficient for the detection of tropical fish specific‐IgE.

Transient paralytic ileus following the use of cyclopentolate−phenylephrine eye drops during screening for retinopathy of prematurity

Abstract:  Cyclopentolate−phenylephrine eye drops are commonly used for mydriasis during routine screening for retinopathy of prematurity in preterm infants. Although systemic absorption is minimal, it can result in side effects. We report two cases of transient paralytic ileus associated with transient oxygen desaturation and hypertension following the use of cyclopentolate−phenylephrine eye drops.

Thalidomide in Behçet’s disease

Behçets disease is a chronic relapsing multisystem disease of unknown aetiology. It has a relapsing cyclical course, and is characterized by the triad of aphthous stomatitis, genital ulcerations and uveitis. There is familial and geographical clustering of cases, especially around the Mediterranean, the Middle East and East Asia. The condition is uncommon, but lesions sometimes are recalcitrant and can be debilitating to the affected individual. The treatment of Behçets currently involves the use of steroids, immunomodulaters and immunosuppressives. Thalidomide has been used in cases of Behçets disease with some success. This review will discuss Behçets disease and the current information we have about using thalidomide for its treatment.

Anaphylaxis after hamster bites – identification of a novel allergen

Background Hamsters are popular household pets and anaphylaxis after their bites have described. However, the putative allergen has not been identified.

Prevalence of allergy-related symptoms in Singaporean children in the second year of life

This study describes the cross‐sectional prevalence of symptoms associated with eczema (chronic itchy rash), asthma (wheeze), and allergic rhinitis (rhinoconjunctivitis) in 1026 subjects between 18.5 and 23 months old (median age is 21 months) in Singapore. The first 2 yr cumulative prevalence of chronic itchy rash, wheeze, and rhinoconjunctivitis were 22.1% (n = 227), 22.9% (n = 235), and 8.4% (n = 86) respectively. In total, 42.2% (414 of 979) reported ever having any of these symptoms. Eczema, although prevalent, was diagnosed only in 34.4% (n = 78) of children with chronic itchy rash. Children with this eczematous rash were also more prone to wheeze (cOR = 2.0, 95% CI: 1.2–3.0) and rhinoconjunctivitis (cOR = 2.0, 95% CI: 1.4–2.8). Similarly, subjects who reported rhinoconjunctivitis and chronic itchy rash were 2.4 times (95% CI: 1.6–3.6) and 1.4 times (95% CI: 1.0–2.0) more at risk of wheezing respectively. Family history of allergy was a significant risk factor for chronic itchy rash (aOR = 1.8, 95% CI: 1.3–2.4) and wheeze (aOR = 1.7, 95% CI: 1.3–2.4). Thus, symptoms related to allergy were already prevalent during the second year of life. Significant proportions of these symptoms are likely to be due to true atopy as strong relationship with familial history and comorbidity with other potential allergic symptoms were observed.

Low prevalence of latex sensitivity in South African spina bifida children in Cape Town.

Spina bifida children have a high prevalence of latex allergy in studies reported from Europe and the USA. This study investigated the prevalence of latex allergy in a cohort of 24 spina bifida children at the Red Cross Childrens Hospital from Cape Town, South Africa. The children were investigated using a detailed questionnaire, skin prick tests (ALK‐Abello), ImmunoCap RASTs, Western blotting and ELISA, using the purified latex proteins Hev b1 and Hev b3 and whole latex preparation. A low overall prevalence of latex sensitization of 16.7% was found in the children. Children who were sensitive reacted to water insoluble to Hev b1 and Hev b3 proteins. The low prevalence of latex sensitization in the South African children may not be entirely explained by stringent latex avoidance. The children were from a low socioeconomic social status and ‘hygiene’ and other factors should be considered.

Viewpoint: are doctors responsible for the increase in allergic diseases?

There is no exact explanation for the increase in allergic diseases that occurred since the last two decades. An increased allergen exposure and/or a decreased bacterial load cannot explain the phenomenon completely. Other causal factors that rose at the beginning of the 1980s must be taken into consideration. Important changes at that time in our management of children were the worldwide switch from aspirin to paracetamol, the introduction of broad‐spectrum antibiotics such as cephalosporins and the advice to avoid dust and pets in newborns from allergic families. General application of these new approaches, in itself or in combination, might be responsible, at least in part, for the increase of allergic diseases in children.

Epinephrine auto-injector prescriptions as a reflection of the pattern of anaphylaxis in an Asian population.

This study surveyed the prescription patterns of adrenaline auto-injectors (AAs) in Singapore to examine the frequency, triggers, and demographic pattern of anaphylaxis requiring such prescriptions. A 6-year retrospective review of 417 consecutive patients prescribed AAs in Singapore from January 1999 to December 2004, as identified from hospital pharmacy records. There were 417 patients identified, consisting of 295 (70.7%) Singaporeans with the remaining being non-Singaporean residents. Based on population census, the frequency of AA prescriptions was estimated at 1 per 10,000 Singaporeans. Demographic factors associated with AA prescriptions were male gender (OR = 1.361; p = 0.002); minority ethnic groups, which included Eurasians, Caucasians, Koreans, and Japanese (OR = 15.873; p < 0.001); and children <15 years of age (OR = 2.593; p < 0.001). The most common food allergens resulting in AA prescriptions were peanut (41.9%) and shellfish allergy (28.5%). Multiple logistic regression analysis showed that peanut allergy was independently associated with Eurasian ethnicity (OR = 5.045; p = 0.021); and shellfish allergy with Indian ethnicity (OR = 2.757; p = 0.034). The estimated frequency of AA prescriptions in Singapore is relatively low at 0.01%. The incidence of peanut and shellfish allergy in the Asian population appears to differ from that seen in Western populations.

Anaphylaxis after hamster bites—Identification of a novel allergen

BACKGROUND Hamsters are popular household pets and anaphylaxis after their bites have described. However, the putative allergen has not been identified. OBJECTIVE This study was conducted to identify the allergen causing dwarf hamster (Phodopus sungoris) bite-induced anaphylaxis. METHODS Two children with hamster bite-induced anaphylaxis were enrolled. They both had negative results to skin testing and specific IgE to hamster epithelium. However, they were both allergic to Dermatophagoides pteronyssinus (Der p). Identification of the putative IgE-binding allergens from the hamster saliva was performed using immunoblot analysis. RESULTS A specific IgE-binding component at 21 kD in the hamster saliva was identified. ELISA inhibition tests showed partial inhibition with Der p. CONCLUSIONS The putative allergen from the hamster saliva causing dwarf hamster-induced anaphylaxis was identified. Possible cross-reactivity with Der p was demonstrated. Further studies will be needed to identify the exact nature and function of this allergen.