Which of the following statements about electrotherapy is true?

The statement that electrotherapy uses electrical currents for skin treatment is accurate and highlights the primary function of this technique. Electrotherapy encompasses a range of procedures that leverage electric currents to aid in various skin treatments, including improving circulation, stimulating collagen production, and enhancing product penetration into the skin. This method can help address various skin concerns, making it a versatile tool in both esthetics and dermatological care.

The other options fall short in their representation of electrotherapy. For instance, electrotherapy is not involved in hair coloring, making the first statement incorrect. While it can be applied to the scalp in certain treatments, it is not limited to this area, which invalidates the claim of applicability solely to scalp treatments. Furthermore, while some electrotherapy methods might involve manual techniques, many are based on the use of devices and machines to deliver the electrical currents, contradicting the idea that it relies solely on manual application methods.