An adolescent male presents with itching in the inguinal region and a peripherally spreading, sharply demarcated lesion. What is the most likely diagnosis?

The most likely diagnosis for an adolescent male presenting with itching in the inguinal region accompanied by a peripherally spreading, sharply demarcated lesion is indeed tinea cruris. This condition, also known as "jock itch," is a fungal infection that primarily affects the groin area, including the inner thighs and buttocks.

Tinea cruris is characterized by its annular shape with well-defined borders and may exhibit scaling or redness, particularly around the edges of the lesion. The itching associated with this condition can be quite intense, which is consistent with the symptoms presented. Tinea cruris is often caused by dermatophytes, which thrive in warm, moist areas, making the groin a common site for infection.

The other conditions mentioned have different presentations. Poor hygiene may lead to various skin issues but would not typically be characterized by a sharply demarcated lesion with itching. Tinea versicolor, on the other hand, is a superficial fungal infection that causes discolored patches on the skin, typically on the trunk, but does not usually cause significant itching or affect the groin area. Pediculosis pubis, which refers to a lice infestation in the pubic area, would present with intense itching and possibly visible lice or