Unmasking Incontinentia Pigmenti: A Multimodal Clinico-Dermoscopic and Pathologic Correlation

Incontinentia pigmenti (IP) is a rare, X-linked dominant genodermatosis caused by mutations in the IKBKG gene and characterized by sequential cutaneous stages following the lines of Blaschko. The highly inflammatory initial vesiculobullous stage frequently mimics severe neonatal infections, such as herpes simplex or bullous impetigo, leading to potentially dangerous diagnostic delays and unnecessary antimicrobial therapies. The objective of this report is to highlight the utility of multimodal medical imaging and clinico-pathologic correlation in the rapid diagnosis of early-stage IP. We present the case of a full-term female neonate presenting on the third day of life with a rapidly disseminating blistering eruption, initially treated as a widespread infectious process. A multimodal diagnostic approach was applied, incorporating bedside clinico-dermoscopic evaluation of the infant and her mother (who reported a history of early miscarriages), followed by neonatal skin biopsy, immunohistochemistry (S-100, MART-1), and subsequent genetic testing. Dermoscopy of the neonate's transitional lesions revealed early dermal melanophage accumulation, while maternal evaluation exposed pathognomonic residual Blaschko-linear dyspigmentation featuring a distinct "pepper-like" dermoscopic pattern. Histopathology demonstrated classic eosinophilic spongiosis, intraepidermal vesicles, and early pigment incontinence. Genetic testing confirmed recurrent IKBKG exon 4-10 deletion. Crucially, this rapid diagnosis facilitated immediate targeted ophthalmologic screening, detecting asymptomatic stage 2B retinal vasculopathy. Integrating noninvasive dermoscopy with precise histopathologic correlation offers a rapid, highly effective framework to distinguish early IP from neonatal blistering infections. Timely multimodal imaging is crucial for triggering immediate multidisciplinary screening, effectively preventing severe, irreversible vision-threatening complications.