Histopathology of acneiform eruptions in patients treated with epidermal growth factor receptor inhibitors.

BACKGROUND: Epidermal growth factor receptor inhibitors (EGFRIs) are anticancer agents that have been approved for use in a variety of solid tumors. EGFR-inhibiting agents produce a variety of cutaneous adverse events: most commonly a follicular papulopustular (acneiform) eruption on the face, scalp, chest and upper back. OBJECTIVE: The goal of this manuscript is to elucidate the histopathologic findings associated with this most common adverse event. METHODS: The histopathological findings of 10 patients with papulopustular eruptions induced by EGFRIs are described and compared to the four prior published case series of acneiform rashes attributed to EGFRIs. RESULTS: All 10 patients in our case series showed a superficial, predominantly neutrophilic suppurative folliculitis with ectatic follicular infundibula and rupture of the epithelial lining. Similar pathology was found in the four other case series discussing this phenomenon. CONCLUSION: While the characteristic clinical appearance of this rash precludes the need for a biopsy in most cases, this knowledge promotes our understanding of the pathophysiologic process. As the use of EGFRIs expands, dermatopathologists will see these reactions more commonly and will need to recognize this pattern.

Primary cutaneous Nocardia brasiliensis infection isolated in an immunosuppressed patient: a case report.

Cutaneous nocardiosis is a rare infection that may manifest as a superficial skin lesion, lymphocutaneous infection, mycetoma, or diffuse cutaneous infection from a disseminated systemic infection. We report a case of a 65-year-old immunocompromised man with persistent primary cutaneous Nocardia brasiliensis infection following a motor vehicle collision. A high degree of suspicion is needed to diagnose Nocardia infection because of its resemblance to other bacterial infections. Nocardiosis should be included in the differential diagnosis of chronic cutaneous infections, especially when the response to antibiotics is inadequate or when the patient is immunocompromised. Because Nocardia may take several weeks to grow in standard bacterial culture media, laboratories should be notified of the suspicion so that culture plates are held for longer time periods. Long-term therapy, usually with sulfonamides, often is necessary.

Hand hygiene in the dermatologist's office: to wash or to rub?

Hand hygiene is a central factor in preventing the spread of disease in the dermatologist's office. The role of hand washing and alcohol-based hand rubs is considered with emphasis on compliance, effectiveness, side effects, and cost. Specific recommendations highlight the importance of using alcohol-based hand rubs as an adjunct to traditional hand-washing methods.

Differential diagnosis of chronic urticaria.

OBJECTIVES: To review diseases that can present with cutaneous signs and symptoms that mimic those observed in chronic urticaria and to discuss the workup necessary to distinguish these diseases from chronic urticaria. DATA SOURCES: We performed a PubMed search using the following keywords: urticaria, cryopyrin, Sweet syndrome, subacute cutaneous lupus, urticarial vasculitis, urticaria pigmentosa, angioedema, fixed drug eruption, bullous pemphigoid, and reticular erythematous mucinosis. Appropriate chapters in general dermatology textbooks were also reviewed. STUDY SELECTION: Articles that related to disease states, which present with persistent urticarial lesions, were catalogued for use in this review. RESULTS: Besides acute, chronic, and physical urticarias, there are 2 categories of diseases that have urticarial lesions. The first group includes those in which the skin lesions are almost indistinguishable from those seen in patients with chronic idiopathic urticaria. Thus, the diagnosis relies on a careful history and physical examination, and in some cases laboratory studies are required. The second group are ones that have skin lesions that at one point in their development have an urticaria-like appearance or on rare occasion may have such lesions. These latter diseases are numerous, and we have tried to highlight the ones that most mimic chronic idiopathic urticaria or are more common. CONCLUSIONS: A working knowledge of the diseases that can present with urticarial lesions is essential to accurately diagnose and effectively treat these symptomatic and sometimes serious conditions.

Pathophysiology of chronic urticaria.

OBJECTIVE: To review the literature on the pathogenesis of chronic urticaria (excluding physical urticaria). DATA SOURCES: PubMed was searched using the keywords urticaria and either chronic or autoimmune or pathogenesis for articles published from January 1972 to June 2007. All searches were limited to the English language. References from review articles on chronic urticaria were also considered for inclusion in this review. STUDY SELECTION: The authors selected relevant and current sources for inclusion in this review. RESULTS: No concise pathogenic mechanism has been identified for all cases of chronic urticaria, although evidence for a serologic mediator that may be autoimmune in nature has been identified in many cases. The activation of basophils and/or mast cells is a central feature in any theory proposed to explain this troubling disease. CONCLUSION: Further research is needed to better define the mechanism or mechanism(s) responsible for the development of chronic urticaria. Such research will lead to more effective and possibly even curative treatments.