Background: Pathologic examination of Acute Generalized Exanthematous Pustulosis (AGEP) and Pustular Psoriasis (PP) are similar. We encountered many patients with PP or AGEP who cannot be distinguished clinically, pathologically and based on disease course from each so we designed a comprehensive interpersonal histopathologic overview of these patients' samples.

Method: Histopathological data of 16 patients over 3.5 years were analyzed. Four pathologists separately reviewed specimens based on eighteen criteria (9 Epidermal and 9 Dermal). Severity score for each criterion was considered as to be (0 to 3+). We compared the final pathologic diagnosis with primary one.

Results: Neutrophilic and lymphocytic infiltration in dermis were seen in all cases of AGEP while intraepithelial pustules. Subcorneal and intraepithelial pustules, spongiosis, neutrophilic exocytosis, neutrophilic and lymphocytic infiltration in dermis were observed in all cases of PP. The most severe neutrophilic inflammation; acanthosis and neutrophilic or lymphocytic infiltration were seen in PP.

The authors of this study have been reported generalized pustular clinical presentations of patients have been taken HCQ, and in the recent pandemic it is also one of the concerns that many studies have been focused (....).

Conclusion: When primary histopathologic report is AGEP/PP overlap, clinical judgment is the best way to manage and it is more probable that the final diagnosis being PP. When only AGEP or PP is histopathologic diagnostic report, it is usually enough to make final diagnosis and appropriate management.

Key words: hydroxychloroquine, HCQ, generalized pustular cutaneous eruption, Pustular Psoriasis (PP), Acute Generalized Exanthematous Pustulosism, AGEP, Histopathological overview, pathology, review