There are a few diagnoses that come in mind. Contact dermatitis or an allergic reaction is the most likely source of an itchy skin lesion. Ringworm infections by the tinea species of fungus can appear as dark itchy spots. Pityriasis Rosea can also present as a dark/red spot on the skin and spread for weeks before resolving. Syphilitic lesions and Kaposi’s sarcoma (for HIV positive patients) also fits the description very well. Therefore, you will need to be examined by your primary care physician or a dermatologist to determine the cause of your lesions.
