The patch test, skin prick test, and serum milk‐specific IgE as diagnostic tools in cow's milk allergy in infants

Abstract

We evaluated the value of the patch test, skin prick test, and milk‐specific IgE by CAP RAST in 301 infants with suspected hypersensitivity to cow's milk. The patch test was carried out with milk powder, and the skin prick test with cow's milk‐based formula. Hypersensitivity to cow's milk was determined with double‐blind, placebo‐controlled challenge. An immediate reaction to cow's milk challenge was observed in 100 infants (33%), a delayed reaction in 76 (25%), and a negative result in 125 (42%). Skin prick test wheals were significantly greater in infants with immediate reactions than in infants with delayed or negative reactions. Milk‐specific IgE was correlated with the skin prick test (r=0.78, P<0.001, n=268) but did not contribute to further discrimination of immediate reactions from delayed or negative reactions compared to skin prick test alone. In our study population, the skin prick test (diameter ≥3 mm) showed a specificity and sensitivity of 91% and 69%; the results for milk‐specific IgE (≥0.7 kU/l) were 88% and 58%, respectively. The patch test did not distinguish subjects with immediate or delayed reactions from those with negative reactions.

Skin Localization of Cow’s Milk Proteins Delivered by a New Ready-to-Use Atopy Patch Test

“…This result is important because it suggests that the E-patch \ would probably not promote systemic delivery of intact proteins, thereby reducing the possibility of systemic anaphylactic shocks. This is in agreement with the fact that no incident of anaphylactic shock has been described during clinical trials of APT (1,5,15,31).…”

“…It has been described that this type of reaction, accompanied by occasional palpable infiltration or eczema, tends to grow stronger between 48 and 72 h (1,12,15,16). This inflammatory reaction on the skin is mainly caused by the liberation of histamine.…”

“…In particular, hypersensitivity to cow's milk occurs in 2Y3% of infants (1,2). The recommended test, or Bgold standard^, in the diagnosis of food allergy is the double-blind, placebo-controlled food challenge (3).…”

“…This occlusive delivery system is intended to be prepared and secured on the skin of children by the medical practitioner. The occlusion time is 48 h and the results are read 24 h later (1,5,15). However, these tests suffer from many drawbacks including the absence of standardization (13,15Y17).…”

Diagnosis and Management of Cows' Milk Protein Allergy in Infants

“…None of the diagnostic tests available in routine clinical situations prove or exclude CMPA completely (11). A thorough history, including family history of atopy, and a careful clinical examination are therefore the key elements in the diagnostic process.…”