Your doctor can make the diagnosis just by looking. This should be removed by regular washing, otherwise irritation and possibly an infection can develop. Pull the foreskin back, clean the head of the penis, then place the foreskin back in its normal position. Balanitis is inflammation of the head of the penis caused by trauma or poor hygiene. The area is red, swollen and tender.
Treatment is with warm compresses and an oral antibiotic.
Eczema is a dry, itchy, scaly rash. Eczema of the scrotum can be intensely itchy with thickening and darkening of the scrotal skin. Treatment is with a mild skin cleanser, moisturizer and a mild topical steroid. Contact dermatitis is an allergic reaction. One common cause is poison ivy, which you can get on your hands and spread to your genitals by touch.