A body found in a forest shows multiple small, irregular, abraded lesions clustered around the eyelids, nostrils, and corners of the mouth, initially suspected to be antemortem abrasions. Histology shows loss of the superficial epidermis with sharply defined, irregular margins and no vital reaction. Which finding best supports these lesions as postmortem arthropod artefacts?

• A Absence of vital reaction with lesions concentrated at natural orifices and thin skin ✓
• B Lesions confined to areas where clothing pressed against skin
• C Presence of haemosiderin in the lesion bases
• D Symmetrical distribution over bony prominences of the back

Explanation

Ants, cockroaches, and other arthropods feed preferentially at natural openings and moist thin skin such as eyelids, lips, and genitals, producing irregular serpiginous or abraded defects lacking any inflammatory vital reaction because they were inflicted after death. Pressure areas and bony prominence distribution suggest antemortem or perimortem injury, and haemosiderin indicates a reaction formed while alive.

Reference: Knight's Forensic Pathology, 4th ed.

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Written and medically reviewed by the StethoPrep medical team.