Diabetic Dermopathy: This condition is common in diabetic patients and presents as superficial skin lesions that resemble abrasions or scars. The absence of pruritis and the patient's diabetic status support this diagnosis.

Ecchymoses or Senile Purpura: These conditions can cause petechiae and are common in older adults, especially those with diabetes who may have vascular complications.
Contact Dermatitis: Although the patient reports no pruritis, some forms of contact dermatitis can present with minimal itching, and the appearance can sometimes mimic an abrasion.
Stasis Dermatitis: This condition, related to venous insufficiency, can cause skin changes and petechiae, especially in the lower extremities, and is more common in diabetic patients due to vascular complications.

Vasculitis: Although less common, vasculitis (including conditions like leukocytoclastic vasculitis) can present with petechiae and skin lesions. Missing this diagnosis could lead to significant morbidity due to the potential for organ involvement.
Meningococcemia: This is a life-threatening condition that can present with a rash (often petechial) and requires immediate recognition and treatment. Although the patient's presentation does not strongly suggest this, it's a critical diagnosis not to miss.
Disseminated Intravascular Coagulation (DIC): In the context of severe infection or other systemic conditions, DIC can cause petechiae and purpura. Given the patient's diabetic status, which may predispose to infections, this is an important consideration.

Amyloidosis: Cutaneous amyloidosis can cause macular or papular lesions and, in some cases, may resemble an abrasion. However, this is less common and typically associated with other systemic symptoms.
Scurvy: Vitamin C deficiency can cause perifollicular petechiae and corkscrew hairs, among other symptoms. Although rare in developed countries, it should be considered in malnourished patients or those with poor dietary intake.