Interpreting Cytomegalovirus Seropositivity Beyond the Neonatal Diagnostic Window: A Case Report on an Infant With Early-Onset Atopic Dermatitis and Congenital Arthrogryposis

Congenital cytomegalovirus (cCMV) infection has a broad clinical spectrum and may result in permanent neurological, auditory, visual, and developmental sequelae.We report the case of a six-month-old male infant investigated primarily for microcephaly who had a complex phenotype comprising a cutaneous rash present from birth that evolved into moderate early-onset atopic dermatitis with severe clinical and qualityof-life impairment, growth impairment, congenital arthrogryposis, neonatal jaundice with hyperbilirubinemia, mild neonatal thrombocytopenia, and neurosensory abnormalities.He was born at 36 weeks and four days after reduced amniotic fluid volume was noted at approximately 36 weeks.Neonatal hyperbilirubinemia did not require phototherapy, and a follow-up peripheral blood smear was unremarkable.At six months, the dermatitis consisted of widespread erythematous-squamous, intensely pruritic lesions with facial and periorbital involvement and sleep disturbance.After 40 days of conventional treatment with emollients, skin-barrier care, and topical corticosteroids, the SCORAD (Scoring Atopic Dermatitis) index decreased from 45 to 18, although residual lesions persisted.Growth was impaired, with marked underweight (weight-for-age z-score <-3) and reduced linear growth (length-for-age z-score -2.6), while head circumference was 40.8 cm (z-score -2.2), consistent with microcephaly.Brain magnetic resonance imaging showed preserved cerebral architecture with symmetric periventricular and peritrigonal T2 hyperintensity considered indeterminate and potentially related to incomplete physiological myelination.Auditory brainstem evoked responses and visual evoked potentials were abnormal.Creatine kinase was mildly elevated, whereas neurological examination and electromyography were normal.Quantitative immunoglobulins, serum protein electrophoresis, and lymphocyte subset analysis were unremarkable.Maternal CMV-specific IgM and IgG were positive during the eighth month of pregnancy, and the infant had positive CMV-specific IgM and IgG at six months.In the absence of virological testing within the first 21 days of life or an archived neonatal dried blood spot, congenital infection could not be definitively confirmed.This case emphasizes the critical importance of recognizing suggestive neonatal findings and testing for cCMV within the first 21 days of life, particularly in settings where retrospective dried-bloodspot testing is unavailable.