Hot tub folliculitis: This is the most likely diagnosis if the patient has recently used a hot tub, especially if the water was not properly chlorinated. The condition is caused by Pseudomonas aeruginosa bacteria, which thrive in warm, moist environments.
Atopic dermatitis: If the patient has a history of atopic diseases (such as asthma or allergies) and presents with chronic, itchy skin lesions, atopic dermatitis is a strong consideration.

Contact dermatitis: This could be a consideration if the patient has come into contact with an irritant or allergen, such as soap, shampoo, or other chemicals.
Irritant dermatitis: Similar to contact dermatitis, but caused by exposure to substances that directly damage the skin, such as harsh soaps or excessive heat.
Seborrheic dermatitis: If the patient presents with a scaly, itchy rash on the scalp, face, or torso, seborrheic dermatitis could be a likely diagnosis.

Staphylococcal scalded skin syndrome (SSSS): Although rare, SSSS is a serious condition caused by staphylococcal toxins that can lead to widespread skin lesions and potentially life-threatening complications.
Eczema herpeticum: A potentially serious complication of atopic dermatitis, where the skin becomes infected with the herpes simplex virus, leading to widespread, painful lesions.

Keratosis pilaris: A rare condition characterized by small, rough bumps on the skin, often on the arms or legs.
Pityrosporum folliculitis: A rare fungal infection of the hair follicles, which can cause itchy, inflamed lesions.
Erythema toxicum neonatorum: A rare condition that affects newborns, characterized by small, yellow or white bumps on the skin.