Neural reactivity detected by immunofluorescence in a patient with a localized blistering disease

Multiple clinical etiologies exist for rapidly appearing skin blisters are multiple. Case report: A 69-year-old male from a rural area of Georgia, USA, was evaluated for the presence of suddenly appearing, localized erythema and edema on his leg with a skin blister. At presentation, the patient was taking multiple medications for other medical issues. Methods: Skin biopsies for hematoxylin and eosin (H&E) examination, as well as for direct immunofluorescence, indirect immunofluorescence and immunohistochemistry studies were performed. Results: H&E staining demonstrated a subepidermal blistering process. Within the dermis, a mild, superficial, perivascular and perineural infiltrate of lymphocytes, histiocytes and eosinophils was seen. Direct and indirect immunofluorescence revealed focal dermal perineural and free epidermal nerve fiber staining utilizing antibodies to human Complement/C1q, C3, C4, kappa and lambda light chains. Immunohistochemistry studies revealed IgG, IgE, C3, fibrinogen, albumin and kappa deposition inside and around the blister. Conclusions: Our case has some clinical and epidemiological features that resemble localized bullous pemphigoid, however, the most interesting findings were the neural reactivity without concomitant diabetes or peripheral neuropathy. Notably, a concomitant leak of ricin was simultaneously detected in same geographic area as the patient. We suggest that ricin environmental toxicity may have contributed to the observed neural reactivity.