Background: A severe form of fixed drug eruption (FDE) clinically and histologically mimics toxic epidermal necrolysis (TEN) but, unlike TEN, resolves spontaneously upon withdrawal of the causative drug. Objective and Methods: We reported a case of a severe FDE caused by mefenamic acid that spontaneously resolved without use of systemic corticosteroids. To clarify the phenotype of the T cells responsible for clinical resolution of FDE, we kinetically examined γ-interferon (IFN-γ), interleukin (IL)-2, IL-4 and IL-10 production by peripheral blood T cells of the patient before and after oral challenge with the causative drug using flow cytometry. Results: We found that the proportions of CD4+ and CD8+ T cells capable of producing IFN-γ and IL-4 remained unchanged after challenge, while those of CD4+ and CD8+ T cells capable of producing IL-10 dramatically increased after challenge. The frequency of CD8+ T cells capable of producing IL-2 decreased after challenge. Conclusion: These results suggest that expansion of IL-10-producing CD4+ and CD8+ T cells may be responsible for spontaneous resolution of a severe form of FDE.

Skin rash associated with hepatitis A virus infection has rarely been reported. We describe a patient with hepatitis A virus infection who presented a rubelliform rash markedly accentuated in sun-exposed areas; direct immunofluorescence studies of the lesion revealed immunoglobulin (Ig) A deposition on the endothelial cells in the upper dermis. Oral rechallenge tests of the previously administered drugs failed to reproduce the eruption. The preferential setting of immune complexes containing IgA at sites of sun exposure and sunlight as a triggering factor might have been responsible for the development of the eruption in this patient. Eruptions associated with hepatitis A virus infections may be more frequent than commonly thought. Because of difficulty to exclude the possibility of drug eruptions, these cases might have been overlooked. In patients with such a disorder, a careful clinical workup such as IgM antibodies for hepatitis A virus at diagnosis and during follow-up is especially recommended.