Which of the following is NOT a type of infection commonly dealt with in salons?

Psoriasis is a chronic skin condition characterized by the rapid growth of skin cells that leads to scaling and inflammation. Unlike infections, which are caused by pathogens such as bacteria, fungi, or viruses, psoriasis is an autoimmune disorder and is not contagious.

In contrast, the other options listed are all infections that can be transmitted from person to person or through contaminated surfaces in a salon environment. Tinea pedis, commonly known as athlete's foot, is a fungal infection that affects the feet. Scabies is caused by tiny mites that burrow into the skin, leading to intense itching and inflammation. Ringworm, or tinea corporis, is also a fungal infection that can appear on various parts of the body and is known for its ring-like appearance.

Therefore, while tinea pedis, scabies, and ringworm are infections that salon professionals might encounter and need to manage, psoriasis is not classified as an infection and is therefore the correct choice for this question.