Clinicomorphological correlation of psoriasis and psoriasiform dermatitis

Abstract

Introduction: Psoriasis is a chronic inflammatory skin disorder. Psoriasiform dermatitis on other hand is a frequently encountered terminology in a variety of inflammatory dermatoses. It often poses challenges to both dermatologists and pathologists alike. Clinical features when considered alone may not be reliable to differentiate psoriasis from psoriasiform dermatitis. Aims: (a)To correlate the clinicomorphological features of psoriasis and psoriasiform dermatitis. (b)To identify determinants that may contribute to the diagnosis of psoriasis and psoriasiform dermatitis. Methods: This is a prospective study of 40 cases. Cases clinically diagnosed as psoriasis and psoriasiform dermatitis were screened microscopically and as per morphological criterias 20 cases from each entity were selected and included in the study. Detailed histopathological analysis and correlation was done. Results: The clinical features of typical scales (p= 0.0012) and Auspitz's sign (p = 0.058) morphological evidence of regular acanthosis (p= 0.0005), absent granular layer (p = 0.0001) and presence of micromunros abscess (p=0.0001) were found to be statistically highly significant contributors to the diagnosis of psoriasis in comparison to psoriasiform hyperplasia. Other morphological features like suprapapillary thinning (p= 0.051) was also found to be morphologically significant. Vertical orientation of collagen bundles (p = 0.002) was found to be significantly associated with diagnosis of psoriasiform hyperplasia when compared to psoriasis. Conclusion: The present study reconfirms the diagnostic accuracy of scales, Auspitz’s sign as clinically reliable signs of psoriasis. However, in their absence, morphological presence of regular acanthosis, absent granular layer and Munro microabscess may contribute to the diagnosis of psoriasis. Similarly, vertical orientation of collagen bundles points toward a diagnosis of psoriasiform dermatitis. This may help clinicians not to miss the diagnosis of clinically insignificant psoriasis in order to start early treatment and prevent the poor prognosis in these patients.