Faculty Bibliography

Poison ivy, poison oak, and poison sumac are the most common causes of clinically diagnosed allergic contact dermatitis in North America. Approximately 50% to 75% of the US adult population is clinically sensitive to poison ivy, oak, and sumac. We reviewed the botany and history of these plants; urushiol chemistry and pathophysiology, clinical features, and the prevalence of allergic contact dermatitis caused by these plants; and current postexposure treatment and preventive methods, including ongoing investigations in the development of a vaccine (immunotherapy). Although extensive efforts have been made to develop therapies that prevent and treat contact dermatitis to these plants, there lacks an entirely effective method, besides complete avoidance. There is a need for a better therapy to definitively prevent allergic contact dermatitis to these plants.

Although allergists often evaluate rashes associated with allergic, IgE mediated etiologies, it is important to consider a wide range of differential diagnoses that includes inflammatory, infectious, and autoimmune etiologies. The case of a 58-year-old woman with a 1-year history of progressive pruritic rash that did not improve with topical creams and steroids is presented. The patient did not state any other symptoms, and a physical examination was notable for a widespread rash. After a detailed evaluation of the rash, a differential diagnosis was made, and results of a skin biopsy confirmed a specific diagnosis. Even in the context of a medical history of atopy, one must consider nonallergic causes of rash, including abnormal presentations of systemic conditions. It is important to determine the specific etiology of the rash because this will dictate treatment and prognosis and/or complications of the disease associated with the skin manifestations.

Linear vesicles or papules in a newborn can be a presenting sign of incontinentia pigmenti (IP). In this report, we present two cases of neonates with cutaneous manifestations of incontinentia pigmenti. In one case, mild peripheral eosinophilia was noted. No extra-cutaneous manifestations were noted otherwise in both cases after complete ophthalmological and neurological evaluations. These cases serve as a reminder for clinicians to consider IP in newborns presenting with linear vesicles or papules.

BACKGROUND:Secondary syphilis has a wide spectrum of clinical and histologic manifestations. OBJECTIVE:We sought to determine the frequency of histopathological features characterizing secondary syphilis, and which are most common in specimens displaying few diagnostic findings. METHODS:In a multicenter, retrospective analysis of biopsy-proven secondary syphilis, cases were subcategorized by the number of histologic characteristics present. RESULTS:The 106 cases mostly had 5 to 7 of the features studied. Many features were scarcer in cases with 5 or fewer features, including endothelial swelling (87.7% overall vs 72.4% ≤5 features), plasma cells (69.8% vs 48.3%), and elongated rete ridges (75.5% vs 27.6%). Specimens with 5 or fewer features were more likely to be truncal (61.1% vs 34.4% overall), demonstrate rete ridge effacement (44.8% vs 19.8%), and have pityriasis rosea (33.3% vs 17.2%) or drug eruption (33.3% vs 10.9%) in the clinical differential. An interstitial inflammatory pattern was the most common characteristic of specimens with 5 or fewer features (75.9%). LIMITATIONS/CONCLUSIONS:This was a retrospective review. CONCLUSION/CONCLUSIONS:The independent value of many histologic features of syphilis may be overestimated. Combinations of endothelial swelling, interstitial inflammation, irregular acanthosis, and elongated rete ridges should raise the possibility of syphilis, along with the presence of vacuolar interface dermatitis with a lymphocyte in nearly every vacuole and lymphocytes with visible cytoplasm.

Atypical acquired melanocytic nevi in patients with epidermolysis bullosa (EB) have been referred to as EB nevi and are considered to be a type of recurrent nevus with atypical but distinctive histopathologic findings. Herein, we describe an atypical nevus in a patient with Hailey-Hailey disease with different histopathologic findings from EB nevi because of presumably different pathogenesis. It is important to be aware that the recurrent nevi phenomenon can be seen in acantholytic conditions as well as blistering disorders, given these lesions may clinically resemble melanoma.

Bullous pemphigoid (BP) is an autoimmune blistering disease mediated by autoantibodies targeting BP180 (type XVII collagen). Patient sera and tissues typically have IgG and IgE autoantibodies and elevated eosinophil numbers. Although the pathogenicity of the IgE autoantibodies is established in BP, their contribution to the disease process is not well understood. Our aims were two-fold: 1) To establish the clinical relationships between total and BP180-specific IgE, eosinophilia and other markers of disease activity; and 2) To determine if eosinophils from BP patients express the high affinity IgE receptor, FcεRI, as a potential mechanism of action for IgE in BP. Our analysis of 48 untreated BP patients revealed a correlation between BP180 IgG and both BP180 IgE and peripheral eosinophil count. Additionally, we established a correlation between total IgE concentration and both BP180 IgE levels and eosinophil count. When only sera from patients (n = 16) with total IgE ≥ 400 IU/ml were analyzed, BP180 IgG levels correlated with disease severity, BP230 IgG, total circulating IgE and BP180 IgE. Finally, peripheral eosinophil count correlated more strongly with levels of BP180 IgE then with BP180 IgG. Next, eosinophil FcεRI expression was investigated in the blood and skin using several methods. Peripheral eosinophils from BP patients expressed mRNA for all three chains (α, β and γ) of the FcεRI. Surface expression of the FcεRIα was confirmed on both peripheral and tissue eosinophils from most BP patients by immunostaining. Furthermore, using a proximity ligation assay, interaction of the α- and β-chains of the FcεRI was observed in some biopsy specimens, suggesting tissue expression of the trimeric receptor form in some patients. These studies provide clinical support for the relevance of IgE in BP disease and provide one mechanism of action of these antibodies, via binding to the FcεRI on eosinophils.