Tick Dermatosis

• Local reaction depends on host hypersensitivity and tick's secretions
• Grossly:
  • Focal erosions, erythema, crusted ulcers, sometimes alopecia and nodules
• Microscopically:
  • Epidermal and dermal necrosis
  • Perivascular of diffuse inflammation and necrotic margins
  • Eosinophils, macrophages and lymphocytes in exudate
  • May form granulomas containing collagenous fibres and lymphoid follicles within dermis