Facial Discoid Dermatosis Imaging with Line-Field Confocal Optical Coherence Tomography and Reflectance Confocal Microscopy-A Case Report and Literature Review.

Background/Objectives: Facial discoid dermatosis is a rare inflammatory dermatosis presenting with round, superficial erythematous lesions located on the face. Diagnosis may be challenging and often requires careful clinicopathological correlation due to overlapping clinical and histopathological features. Skin lesions are typically resistant to a wide range of topical and systemic treatments. From the perspective of personalized medicine, improved phenotyping of rare inflammatory dermatoses may support more precise diagnosis, individualized therapeutic decisions, and non-invasive disease monitoring. This study aimed to characterize facial discoid dermatosis using line-field confocal optical coherence tomography and reflectance confocal microscopy and to discuss its differential diagnosis and therapeutic implications. Methods: We report a case of facial discoid dermatosis in a 35-year-old patient examined with line-field confocal optical coherence tomography and reflectance confocal microscopy. The imaging findings were interpreted in correlation with clinical and histopathological features. A literature review was performed to summarize differential diagnoses, therapeutic perspectives, and the proposed relationship between facial discoid dermatosis and pityriasis rubra pilaris. Results: Non-invasive imaging revealed morphological features consistent with a psoriasiform inflammatory dermatosis and provided additional in vivo information supporting the diagnosis. The literature review showed limited evidence for a direct association between facial discoid dermatosis and pityriasis rubra pilaris, with only isolated reports suggesting possible overlap or progression. Conclusions: Facial discoid dermatosis appears to represent a distinct psoriasiform dermatosis. Line-field confocal optical coherence tomography and reflectance confocal microscopy may contribute to a personalized diagnostic approach by supporting differential diagnosis and potentially guiding individualized monitoring in rare inflammatory facial dermatoses.