diff --git a/frontend/src/domains/new_dashboard/components/layout/Header.tsx b/frontend/src/domains/new_dashboard/components/layout/Header.tsx
index d403888..e8a656e 100644
--- a/frontend/src/domains/new_dashboard/components/layout/Header.tsx
+++ b/frontend/src/domains/new_dashboard/components/layout/Header.tsx
@@ -392,13 +392,6 @@ export function Header({
               >
                 Meu Perfil
               </button>
-              <button
-                type="button"
-                onClick={() => setShowUserMenu(false)}
-                className="block w-full px-4 py-3 text-left hover:bg-muted"
-              >
-                Segurança
-              </button>
               <button
                 type="button"
                 onClick={() => {
diff --git a/frontend/tests/unit/new_dashboard/HeaderUserMenu.test.tsx b/frontend/tests/unit/new_dashboard/HeaderUserMenu.test.tsx
new file mode 100644
index 0000000..8226b50
--- /dev/null
+++ b/frontend/tests/unit/new_dashboard/HeaderUserMenu.test.tsx
@@ -0,0 +1,71 @@
+import "@testing-library/jest-dom/vitest";
+import { fireEvent, render, screen } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { Header } from "@/domains/new_dashboard/components/layout/Header";
+
+const mockNavigate = vi.fn();
+
+vi.mock("react-router-dom", () => ({
+  useLocation: () => ({ pathname: "/home" }),
+  useNavigate: () => mockNavigate,
+}));
+
+vi.mock("@/domains/auth/application/AuthContext", () => ({
+  useAuth: () => ({
+    user: { id: "1", name: "Joao Silva", email: "joao@teste.com" },
+    logout: vi.fn(),
+  }),
+}));
+
+vi.mock("@/domains/new_dashboard/infrastructure/notificationsApi", () => ({
+  getDashboardNotificationFeed: vi.fn().mockResolvedValue({
+    messages: [],
+    notifications: [],
+    unreadCount: 0,
+  }),
+  markDashboardNotificationsRead: vi.fn().mockResolvedValue(undefined),
+  clearDashboardNotifications: vi.fn().mockResolvedValue(undefined),
+}));
+
+vi.mock("@/domains/new_dashboard/components/layout/ThemeToggle", () => ({
+  ThemeToggle: () => <button type="button">tema</button>,
+}));
+
+vi.mock("@/domains/new_dashboard/components/layout/MessageDetailModal", () => ({
+  MessageDetailModal: () => null,
+}));
+
+function openUserMenu() {
+  render(<Header />);
+  fireEvent.click(screen.getByLabelText("Menu do usuário"));
+}
+
+describe("Header - dropdown do usuário (PAV-108)", () => {
+  beforeEach(() => {
+    mockNavigate.mockReset();
+  });
+
+  it("AC1/AC4: não exibe a opção 'Segurança' no dropdown superior", () => {
+    openUserMenu();
+
+    expect(
+      screen.queryByRole("button", { name: "Segurança" }),
+    ).not.toBeInTheDocument();
+  });
+
+  it("AC2: exibe a opção 'Ajuda' no dropdown superior", () => {
+    openUserMenu();
+
+    expect(
+      screen.getByRole("button", { name: "Ajuda" }),
+    ).toBeInTheDocument();
+  });
+
+  it("AC3: 'Ajuda' navega para /ajuda (mesmo destino da Ajuda inferior)", () => {
+    openUserMenu();
+
+    fireEvent.click(screen.getByRole("button", { name: "Ajuda" }));
+
+    expect(mockNavigate).toHaveBeenCalledWith("/ajuda");
+  });
+});