The scab on my knee keeps cracking open and oozing yellow fluid.

Cracked scabs on a scraped knee that keep oozing yellow fluid are generally attributed to two factors: tissue fluid exudation or infection with pus formation. The details are as follows:

1. Tissue Fluid Exudation

After a skin injury on the knee, superficial wounds may exude tissue fluid, typically appearing as a light yellow liquid. This is usually a normal sign of wound healing and is not accompanied by other significant symptoms. The discharge will gradually subside naturally. It is important to keep the wound clean and dry. Disinfect the area with iodophor solution; bandaging is generally unnecessary.

2. Infection with Pus Formation

If the wound is not properly disinfected after injury, or if the gauze used for dressing does not meet sterile standards, the wound may become infected. This can lead to the formation of thick yellow pus under the scab. In such cases, additional symptoms like redness, swelling, and a fluctuant feeling beneath the skin are often present. It is recommended to disinfect the wound with iodophor and apply erythromycin ointment to treat the infection. For accumulated pus inside the wound, incision and drainage may be necessary.

In summary, recurring cracked scabs with yellow discharge from a knee scrape are either part of normal healing or caused by bacterial infection. If symptoms are severe, especially with redness, swelling, and pain, patients should seek timely medical attention for further treatment.