Tinea manuum

Tinea manuum is a fungal infection of the hand. It is typically more aggressive than tinea pedis but similar in look. Itching, burning, cracking, and scaling are observable and may be transmitted sexually or otherwise, whether or not symptoms are present. Alternatively, it may be caused by an allergic reaction, known as a "dermatophytid reaction". "For example, a fungal infection on the foot may cause an itchy, bumpy rash to appear on the fingers. These eruptions (dermatophytids, or identity or id reactions) are allergic reactions to the fungus. They do not result from touching the infected area. The eruptions may appear on many different areas of the body at once."
Treatment.
It can usually be treated with long-term use of a topical antifungal medications such as selenium sulfide shampoo. However, in some cases an oral antifungal such as griseofulvin may have to be prescribed.