The inflammatory response in drug-induced acute urticaria: ultrastructural study of the dermal microvascular unit
Article first published online: 31 AUG 2006
Journal of the European Academy of Dermatology and Venereology
Volume 20, Issue 9, pages 1095–1099, October 2006
How to Cite
Criado, P., Criado, R., Valente, N., Queiroz, L., Martins, J. and Vasconcellos, C. (2006), The inflammatory response in drug-induced acute urticaria: ultrastructural study of the dermal microvascular unit. Journal of the European Academy of Dermatology and Venereology, 20: 1095–1099. doi: 10.1111/j.1468-3083.2006.01744.x
- Issue published online: 31 AUG 2006
- Article first published online: 31 AUG 2006
- Received: 9 July 2005, accepted 3 November 2005; DOI: 10.1111/j.1468-3083.2006.01744.x
- adverse drug reactions;
- transmission electron microscopy;
- urticaria ultrastructure;
Background Drug exposure is one of the main aetiologies of urticaria and represents the second most common cause in acute urticarias. Studies involving the ultrastructural aspects of urticaria are relatively rare in the literature. Most of the articles published report on skin biopsies of experimentally induced urticaria, and acute urticaria has been studied even less from a morphological point of view.
Objectives The aims of this study were to observe ultrastructural cell characteristics in five patients with drug-induced acute urticaria and possible aspects of the inflammatory skin response.
Methods Clinical manifestations, light microscopy and transmission electron microscopy were evaluated.
Results With light microscopy, a mild perivascular lymphocyte-monocyte infiltrate was observed with few neutrophils and dermal oedema in skin biopsies of five patients. With electron microscopy, a mild vascular dilatation was observed, with platelets in the lumen and several lymphocytes and dendritic cells close to the superficial dermal vessels. Some mast cells appeared normal, whereas others were granule-depleted. In some areas, mast cells, lymphocytes and satellite dendritic cells were closely associated, as well as some macrophages. A significant number of plasma cells, eosinophils and polymorphonuclear neutrophils were not observed; however, the presence of lymphocytes and macrophages was significant. The epidermis and the dermal-epidermal junction were preserved, except for a discrete oedema in keratinocytes.
Conclusions The ultrastructural aspect of drug-induced acute urticaria is similar to that observed in urticaria caused by Urtica dioica, intradermal histamine and cold urticaria. The presence of the cellular triad with mast cells, dendritic (or satellite) cells and lymphocytes suggests a functional interaction of these cells. These findings support the possible existence of mechanisms in the dermis that may participate in protective and/or injurious vasocentric immune reactions.