A rash on the back of a child's knee can be caused by a number of conditions. Take into consideration the condition of the skin, the presentation of the rash and the child's overall condition when determining the cause of the rash. Most rashes may be uncomfortable but do not last long and can be easily treated at home.
What Does it Look Like?
Examine the rash carefully. Rashes can be raised, flat, pimply or patchy. Notice whether the rash resembles little bumps, are fluid-filled, or feel dry and scaly. A rash may be any shade of red, from very light to almost purple in color. Besides the back of the knees, check to see whether other areas of the body are affected. Look closely at other creases and folds, such as the inside of the elbows.
Heat Rash
A common cause of a rash at the back of your child's knees is heat rash. This appears as a flat, reddened area in the moist folds of the body from sweating. Clean and dry the area and expose it to air. Apply a light powder to keep the area dry.
Contact Dermatitis
Contact dermatitis may result from an allergy or sensitivity to laundry detergent or softener. The back of the knees may come in frequent contact with pants fabric, causing the rash. Contact dermatitis rash presents as raised bumps or patches and can have a slight crusty surface. Switch to hypoallergenic detergents or softeners to see if that makes a difference. Or add a rinse cycle to your child's clothes after washing to remove irritants.
Eczema
Eczema is an inherited tendency toward dry skin and skin allergies. Eczema rash normally presents as dry, flaky white patches, but can also flare up and cause lesions that may turn red and raised. In children, eczema lesions are frequently found on the inside of the elbows and the backs of the knees. Although eczema may be a temporary reaction to a specific allergen, it may also last for several years. Investigate possible food allergies and treat rashes with an over-the-counter hydrocortisone cream.
