Diagnosis and natural course of allergy to cooked potatoes in children.

BACKGROUND: Allergy to heat stable potato proteins can cause severe allergic disease in children. OBJECTIVE: To study diagnostic criteria for allergy to cooked potatoes and to describe its clinical characteristics and natural history. METHODS: Thirty-six children, aged 4-36 months, with atopic symptoms and having a positive potato-CAP and/or skin prick test (SPT) were included. Potato allergy was documented by means of provocation, or elimination and reintroduction or an unequivocal clinical history. Potato-CAP and SPT with a commercial extract were evaluated for diagnostic performance. RESULTS: Presenting symptoms in children with proven potato allergy (n = 17) were eczema (16 of 17), gastrointestinal complaints (eight of 17), urticaria and/or angioedema (five of 17), wheezing/rhinitis (three of 17) and anaphylaxis (two of 17). Fifteen children had previously diagnosed cow's milk protein allergy and were egg-sensitized. Potato-CAP at cut-off >2 kU/l provided a 100% sensitivity and a 62.5% specificity for diagnosis of potato allergy, while a SPT score >/= 3 had a 100% sensitivity and a score >/= 4 had a 100% specificity. Tolerance to cooked potato was achieved in 80% of subjects at age 16-102 months. Of 12 subjects having reached the age of 3 years during the study, 10 were re-evaluated at age 3-6 years: seven of 10 subjects had developed clinical pollen allergy, compared with four of 18 atopic controls (P < 0.05). CONCLUSIONS: Potato-CAP and SPT at specific cut-off are valuable tools in the diagnosis of allergy to cooked potato. Most children with potato allergy develop tolerance at mean age of 4 years. Allergy to cooked potatoes is a risk factor for the development of pollen allergy.

Risk factors for allergy.

UNLABELLED: Host factors involved in the risk for allergy are heredity, sex, race and age, with heredity being by far the most important. Exposure to allergens has been identified as an influential environmental factor, whereas passive smoking and pollution may act as an adjuvant. The atopic mother may during pregnancy add to an atopy-prone environment. Whereas respiratory infections are associated with attacks of bronchial asthma, infections in early life might play a role in the protection against atopy by preferential stimulation of a Th1 response, with mutual down-regulation of the Th2 response. CONCLUSION: Recognition of the risk factors for allergy is important in order to select the factors that could be modified for individuals at risk and in order to identify those factors of which the modulation could evolve in general preventive measures.

Allergenic and antigenic activity of peptide fragments in a whey hydrolysate formula.

BACKGROUND: Milk hydrolysates, although frequently used as substitutes in cases of cow's milk allergy, show a reduced but never a complete abolishment of antigenicity and allergenicity. OBJECTIVE: Our purpose was to determine the lower molecular weight limit of peptides to elicit skin reactions and to bind IgE antibodies in vitro. METHODS: Using FPLC, an ultrafiltrated whey hydrolysate, was fractionated in different molecular weight fractions. Skin-prick tests were performed with the hydrolysate and its fractions in five cow's milk allergic children, and RAST inhibition tests were done using the serum of these children. RESULTS: On the basis of the lowest extinction values between two peaks of the chromatogram, seven fractions with molecular weights between 15000 and 125 Da were obtained. Peptides of > 2600 Da elicited a clearly positive skin reaction and inhibited IgE-binding, while peptides of < 1400 Da did not give any positive skin reaction but were still able to inhibit to a small extent IgE-binding to the hydrolysate. CONCLUSION: Our findings suggest that for skin reactivity peptides of > 1400 Da are needed. The minimal molecular mass for IgE binding in vitro appears to be situated between 1400 and 970 Da. Such peptides might be used to develop a safe formula for patients reacting to milk hydrolysates or even for tolerance induction.

Determination of independent risk factors and comparative analysis of diagnostic methods for immediate type latex allergy in spina bifida patients.

BACKGROUND: Development of allergy to natural rubber latex in spina bifida patients is determined by several risk factors, such as age, number of interventions and atopic disease that are, however, interdependent. Furthermore, several diagnostic procedures have been analysed, but a comprehensive analysis of their diagnostic significance is lacking. OBJECTIVE: To determine the independent major risk factor(s) for development of natural rubber latex allergy and the most valuable diagnostic procedure. METHODS: In aselectively collected spina bifida patients, we correlated existing natural rubber latex allergy with age, sex, atopy and the number of hospitalizations and of surgical interventions in appropriately matched subgroups. Allergy to natural rubber latex was established by application of a latex glove fragment on the skin. Skin-prick tests with glove eluate, a natural latex extract and a commercial latex extract were carried out as were specific IgE measurements by radioimmuno assay (RAST-CAP). The results of the latex application test are compared with the other diagnostic methods. RESULTS: Out of 74 fully evaluated patients, 17 had a positive application test. The number of surgical interventions correlates strongly with the presence of natural rubber latex allergy (P<0.0002), independent of age, sex and presence of atopy. Skin-prick tests with unstandardized allergens made from known high allergenic latex gloves represent the most sensitive diagnostic method, with the highest negative predictive value and a specificity of 0.95. RAST-CAP was the next best method with a specificity of 0.93, a sensitivity of 0.89 and a negative predictive value of 0.97. CONCLUSION: The number of surgical interventions is the major independent determining factor for allergy to natural rubber latex in spina bifida patients. Unstandardized skin-prick tests are the most sensitive and specific diagnostic tool, but RAST-CAP is almost equally performant and therefore a valid alternative.

Acute interstitial pneumonitis and carbamazepine therapy.

A 14-year-old girl with skin rash and acute interstitial pneumonitis is presented. She had been taking carbamazepine for two months. Withdrawal of carbamazepine resulted in a prompt improvement of the clinical picture and a normalization of lung function tests. A hypersensitivity reaction to carbamazepine is suggested and the importance of a skin rash as first sign of a generalized reaction is stressed. Lymphocyte-stimulation-tests with carbamazepine were strongly positive in the patient and not in healthy persons nor in patients taking carbamazepine without adverse effects.