Histopathologic Study of Morbilliform Drug Eruption: Differences between Chemotherapeutic Agents and Antibiotics.

Abstract

BACKGROUND: Cutaneous drug eruption is very common, and its clinical manifestations are variable. Diagnosis of drug eruption is usually based on clinical findings and medication history. To date, few studies have compared the variable histopathologic findings of drug eruption according to medication. OBJECTIVE: We focused on morbilliform eruption among diverse manifestations of drug eruption and investigated the differences in histopathologic findings between antibiotics- and chemotherapeutic-agent-induced morbilliform drug eruption. METHODS: We reviewed medical charts established from March 1998 to August 2016 at our hospital. Inclusion criteria were histopathologically confirmed drug eruptions, clinical demonstrations of typical morbilliform eruptions obtained from medical photographs, and causative drugs identified as chemotherapeutic agents or antibiotics. Immunohistochemical staining was performed and included CD3, CD4, CD8, CD20, CD56, CD68, langerin, CD138, and c-kit. RESULTS: A total of 40 cases (20 cases, chemotherapeutic group; 20 cases, antibiotics group) were included in this study. The most frequent histologic feature of the epidermis was exocytosis (95%) in the chemotherapeutic group and necrotic keratinocytes (100%) in the antibiotics group. Inflammatory infiltration depths were significantly deeper in the antibiotics group than in the chemotherapeutic group. There was no significant difference between the two groups in terms of immunohistochemical staining. CONCLUSION: This study suggested that in patients with morbilliform drug eruption, chemotherapeutic agents cause more superficial inflammation compared to antibiotics. These findings may facilitate the differentiation of the culprit agents of morbilliform drug eruption in cancer patients. Further large, well-designed studies are needed to confirm these findings.