Atypical presentation of a common condition

Cow’s milk protein allergy (CMPA) presents a wide range of clinical manifestations. Although gastrointestinal symptoms are common, they are not always present. In this report, we present two cases of infants with atypical CMPA presentations. Case 1 involves a male newborn who was admitted with polyarthritis and a target-shaped rash, while case 2 features a female newborn who presented with soft swelling of extremities. Both infants had recently started using infant formula, which raised CMPA’s suspicion. An extensively hydrolyzed formula (eHF) was introduced, resulting in the resolution of symptoms, with positive specific IgE measurements supporting the diagnosis. Further, in case 2, she underwent an oral provocation test that confirmed the diagnosis. These cases underscore the clinical variability of CMPA, which can present diagnostic challenges. While specific IgE measurements can offer valuable supporting information, a clinical diagnosis remains indispensable. Awareness of the diverse presentations and a thorough patient history are critical for accurate diagnosis and the prevention of unnecessary treatments.