The capacity of laboratory tests and clinical signs to predict allergi
c manifestations up to 18 months of age was assessed in 129 newborn ba
bies, most of whom had family members with atopic disease. The paramet
ers assessed included family history; skin dryness; erythema toxicum;
skin reactivity to histamine and IgE levels; eosinophil counts; and pe
ripheral white blood cell, leukocyte differential, and platelet counts
in cord blood (CB). Erythema toxicum and white blood cell and platele
t counts were of no value as predictors of allergy. The sensitivity of
family history, skin dryness, and sensitivity to histamine, as well a
s IgE levels and eosinophil counts, varied 25-79% and the specificity
40-74%. The efficiency was never higher than 58%. Logistic regression,
applied in order to evaluate the joint predictive power of the five p
arameters, showed a P value of <0.001. The estimated probability for a
topy before 18 months of age was 0.33 for neonates with normal skin te
xture, a CB IgE of less than 0.5 kU/l, and a history of fewer than two
family members with atopy. The probability increased to 0.89 for babi
es with a dry skin, a history of two or more atopic family members, an
d a CB IgE of greater than or equal to 0.5 kU/l. In conclusion, not on
e parameter nor any combination of them seems suitable for general scr
eening. However, a combination of family history and CB IgE and skin a
ssessment may be used to identify babies at high risk of allergy for p
articipation in prevention studies.