5.5 Electricity, Electrotherapy and Light Therapy: Currents, Modalities, Safety and Contraindications
Key Takeaways
Direct current (DC) flows in one direction, as in batteries, while alternating current (AC) changes direction rapidly, as in wall outlets; a volt measures pressure, an amp measures current strength, an ohm measures resistance and a watt measures power.
Galvanic current is a constant direct current used for desincrustation (negative pole) and iontophoresis; the negative pole is alkaline and softening, and the positive pole is acidic and firming.
High-frequency (Tesla) current is a high-rate alternating current that produces heat and is used for its germicidal and stimulating effects on the scalp and face.
Natural sunlight is about 60% infrared, 35% visible and 5% ultraviolet light; infrared heats and relaxes, and ultraviolet is germicidal but can burn and age the skin.
Electrotherapy is contraindicated for clients with pacemakers or metal implants, heart conditions, epilepsy, pregnancy or broken skin, and the client and barber must not complete a circuit through jewelry or wet hands.
Why Electricity Is Tested
Clippers, dryers, towel warmers and facial machines all run on electricity. The NIC Barber 1 outline lists electrotherapy and light therapy under facial and skin care services, and Virginia's barber curriculum includes machines, equipment and electricity in its 100-hour facial hair and skin care unit. You need the vocabulary, the effects of each current, and above all the safety rules.
Electrical Terms
| Term | Definition | Barber example |
|---|---|---|
| Electricity | The movement of electrons through a conductor | Power to clippers and dryers |
| Conductor | Material that lets current flow easily | Copper wire, metal, water |
| Insulator (nonconductor) | Material that resists current flow | Rubber, plastic, glass, dry wood |
| Complete circuit | The full path from the source, through the appliance, and back | Current flows only when the circuit is complete |
| Direct current (DC) | Flows in one direction only | Batteries in cordless clippers; galvanic machines |
| Alternating current (AC) | Changes direction rapidly | Household and shop outlets |
| Converter | Changes DC to AC | — |
| Rectifier | Changes AC to DC | Battery chargers |
| Volt (V) | Electrical pressure that pushes current | U.S. outlets supply about 120 V |
| Ampere (amp, A) | Strength (amount) of current | A milliampere is 1/1,000 of an amp; facial machines use milliamperes |
| Ohm (Ω) | Resistance to current flow | Wet skin has less resistance than dry skin |
| Watt (W) | Power an appliance uses (volts × amps) | A 1,875-watt blow dryer |
| Fuse / circuit breaker | Opens the circuit when too much current flows, preventing overheating | Reset a tripped breaker only after you fix the cause |
| Ground fault circuit interrupter (GFCI) | Cuts power when current leaks to ground, as through a person or water | Required near sinks under electrical codes (Section 3.3) |
Electrical safety at the station: use UL-listed (or other NRTL-listed) equipment. Never use an appliance with frayed cords or wet hands. Keep cords away from water. Unplug by the plug, not the cord. Don't overload outlets. Disconnect equipment before cleaning it.
Electrotherapy (Modalities)
Facial and scalp machines deliver current through an electrode. An active electrode is applied to the treatment area, and an inactive (indifferent) electrode completes the circuit, often held by the client. Each type of current is called a modality.
| Modality | Current | Main effects and uses |
|---|---|---|
| Galvanic | Constant, direct current that creates chemical (ionic) effects | Iontophoresis pushes water-soluble products into the skin. Desincrustation uses the negative pole to soften sebum in oily skin and comedones |
| Faradic | Alternating, interrupted current | Produces muscle contraction; stimulates and tones muscles at motor points |
| Sinusoidal | Alternating current similar to faradic but smoother | Muscle stimulation with less irritation to sensory nerves |
| High-frequency (Tesla, "violet ray") | High-rate alternating current | Produces heat; germicidal and stimulating; used for oily or acne-prone skin and the scalp |
Galvanic Poles
| Positive pole (anode, red) | Negative pole (cathode, black) |
|---|---|
| Produces an acidic reaction | Produces an alkaline reaction |
| Closes pores; firms (hardens) tissue | Opens pores; softens tissue (desincrustation) |
| Decreases blood supply | Increases blood supply |
| Soothes nerves; reduces redness | Stimulates nerves |
| Pushes acidic (positively charged) products into the skin (cataphoresis) | Pushes alkaline (negatively charged) products into the skin (anaphoresis) |
High-Frequency Application Methods
- Direct: the barber holds the electrode, usually a glass electrode filled with gas, against the client's skin. It is germicidal and stimulating.
- Indirect: the client holds the electrode while the barber's fingers massage the face. The current passes through the barber's hands, and the barber must keep contact with the skin before switching the machine on and off.
- General: the client holds a metal electrode to produce a general toning, warming effect.
Sparking (lifting the electrode slightly) intensifies the germicidal effect but feels stronger. Never use high frequency over alcohol-based products, because sparks can ignite alcohol.
Light Therapy
Natural sunlight is about 60% infrared, 35% visible and 5% ultraviolet light. Light therapy uses lamps or LEDs that deliver specific wavelengths.
| Light | Effects | Precautions |
|---|---|---|
| Infrared (invisible, longest wavelength, warm) | Heats tissue, relaxes muscles, increases circulation, helps products penetrate | Keep the lamp at a safe distance (about 30 inches), limit exposure time, and protect the client's eyes with moist cotton pads |
| Ultraviolet (UV) (invisible, short wavelength) | Germicidal, stimulates vitamin D production, may help some scalp conditions | Can burn the skin and eyes, and causes aging and skin cancer. Use short exposures only under proper training, with eye protection |
| Visible light (the spectrum from red to violet) | Lamps use colors for warmth (red) or soothing (blue) | Protect the eyes |
| LED (light-emitting diode) | Blue light for acne-causing bacteria; red light to stimulate circulation and collagen; yellow and green light for redness and pigmentation are also marketed | Follow manufacturer instructions; avoid with photosensitizing medications or light-triggered conditions |
Contraindications and Precautions
Do not use electrotherapy, and screen carefully before light therapy, for clients who have or are:
- a pacemaker, implanted electronic device or metal implants and plates in the treatment area;
- heart conditions or high blood pressure;
- epilepsy or a seizure disorder;
- pregnant;
- broken, inflamed or infected skin, open lesions or recent injuries;
- broken capillaries or rosacea (avoid heat- and stimulation-producing modalities);
- medications that make them sensitive to light, such as some acne medications and antibiotics.
Remove the client's metal jewelry from the treatment area. Explain each sensation before starting. Turn machines on only after the electrode touches the skin, and off before removing it. Keep current levels low. Disinfect electrodes between clients according to the manufacturer's instructions.
Which galvanic pole is used for desincrustation to soften sebum and open pores on oily skin?
The positive pole, because it produces an acidic reaction
The high-frequency glass electrode
The faradic inactive electrode
The negative pole, because it produces an alkaline, softening reaction
What is the germicidal current that produces heat and is commonly applied with a glass electrode on oily or acne-prone skin and the scalp?
Galvanic current
High-frequency (Tesla) current
Direct current from a battery
Faradic current
Which client should NOT receive a facial electrotherapy treatment?
A client with normal skin who wants a relaxing facial
A client with mild dry skin who wants more moisture
A client who has a pacemaker
A client who requests a cool towel afterward
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