Which type of chemical burn is described as coagulation necrosis with eschar after a chemical spill on the arm?

• A. Acid burn
• B. Alkali burn
• C. Thermal burn
• D. Radiation burn

Answer: (A)

Coagulation necrosis with eschar is the hallmark pattern of an acid burn. When acids contact tissue, they denature proteins and cause precipitation of cellular contents, producing a solid, firm area called an eschar. This coagulative process tends to limit how far the injury penetrates, at least initially, which is why the surface tissue becomes stiff and leathery.

In contrast, alkali burns cause liquefactive necrosis through saponification of fats and proteins, which allows deeper and more extensive penetration. Thermal burns are due to heat injury, and radiation burns arise from radiation damage mechanisms. Thus, the description of coagulation necrosis with eschar after a chemical spill on the arm aligns with an acid burn.