A 24-year-old man presented to our office because of fever and redness of his left lower extremity. The patient had been bitten at his left foot by an insect two days prior to his presentation. He could not recognize the kind of the insect. The patient used a local anti-allergic ointment at the site of the insect bite. He developed fever accompanied by rigors two days after the insect bite. Concomitantly, the patient started feeling a burning sensation on his left lower limb. Physical examination at presentation showed temperature of 38,7° C. The rest of the vital signs and of the physical examination were normal except for findings from the left lower extremity. He had an extensive area with redness, increased local temperature, and tenderness extending from the foot to the upper part of the thigh (Figure 1). On the lateral surface of the left ankle there was a small area of necrosis, at the site of the insect bite (Figure 2). In addition, there were palpable and tender lymph nodes of maximum 2 cm of diameter in the left inguinal area. Routine laboratory tests on admission were normal except for the white blood cells count [12,750 cells/ìl (neutrophils 81,5%, lymphocytes 11,9%)]. The rest of hematological and biochemical tests were normal.
What is the most likely diagnosis?
A. Thrombophlebitis of the major saphenous vein
D. Allergic reaction