Tattoo Removal

Tattooing involves using a tattoo machine or acupuncture method to pierce dye or ink into the skin according to a designed pattern, forming permanent pigmentation. Some tattoos result from foreign objects entering the skin involuntarily, such as through trauma, leading to permanent skin pigmentation. Due to changes in aesthetics, environment, and social requirements, some individuals seek tattoo removal over time.

1. Causes and Pathogenesis

Most tattoos are acquired by young men and women who receive professional, amateur, or cosmetic tattoos for beauty or psychological expression. These tattoos use insoluble colored dyes injected into the dermal layer to form pigmentation. Traumatic tattoos occur when foreign bodies enter broken skin after trauma. These foreign bodies can include glass, metal, soil, or carbonaceous materials, with varying depths of skin penetration.

2. Clinical Manifestations

Clinically, tattoos are classified into professional, amateur, cosmetic, traumatic, and other types.

(1) Professional Tattoos

Professional tattoos have clear color boundaries and uniform dyeing with rich colors. Professional tattooists use tattoo equipment to inject one or more organic dyes into the dermal layer at the same depth. The pigments are more stable physically and chemically than those in amateur tattoos. Common colors and their components include mercury for red, cadmium for yellow, chromium for green, and diamond for blue. Red and yellow pigments tend to fade over time.

(2) Amateur Tattoos

Amateur tattoos have uneven pigment distribution, indistinct edges, and dull colors, typically gray or blue-black. Non-professionals often use carbon or India ink, with varying injection depths. In China, domestic ink is commonly used, which breaks down more easily than India ink.

(3) Cosmetic Tattoos

Cosmetic tattoos, including lip, eyebrow, and eyeliner tattoos, are common among women. They are often done manually or with tattoo machines, using dyes like brown, black, and red ink, which often contain iron ions or ferric oxide.

(4) Traumatic Tattoos

Traumatic tattoos show pigmentation from gray to black, caused by the depth of foreign matter entering the skin after trauma. They often occur on exposed parts like the face and hands. Over months or years, some foreign bodies may encapsulate into granulomas in the dermis or subcutaneous tissue, forming palpable induration.

Adverse Reactions Post-Tattooing

1. Infection: Tattoos can cause local skin infections from viruses, bacteria, or tuberculosis, such as common warts, herpes simplex, folliculitis, and local skin tuberculosis.
2. Allergic Reactions: Allergies to dyes like mercury, chromium, and cobalt compounds can cause contact dermatitis and granuloma, pathologically appearing as tuberculosis-like or sarcoid-like with pigment particles spread throughout the nodule.
3. Changes in Skin Texture: Tattooing can alter local skin texture and cause scars.
4. Malignant Tumors: There have been reports of melanoma, basal cell carcinoma, and squamous cell carcinoma at tattoo sites.
5. Aesthetic Issues: Failed tattoos can result in asymmetric patterns, dull colors, and other appearance issues.

3. Pathological Characteristics

Pathologically, tattoos present as submicron-sized pigment particles of varying shapes and densities in the dermis, often around blood vessels in the superficial and middle dermis layers. Under an electron microscope, tattoos appear as numerous exogenous particles in the dermis, with increased phagocytes engulfing pigment particles.

4. Diagnosis and Differential Diagnosis

This condition can generally be diagnosed based on medical history and clinical manifestations.

5. Treatment

For centuries, various methods have been tried to remove tattoos. Currently, non-laser methods cause more local damage and serious side effects like scars and pigment abnormalities, leading to their gradual elimination.

(1) Q-Switched Laser

Q-switched laser is the most effective method for treating undesirable tattoos with minimal adverse reactions. The treatment mechanism is based on the principle of selective photothermal action, where pigment particles absorb laser energy, expand, break into smaller fragments, and are then shed through the body or excreted by phagocytic cells via lymphoid tissue.

1. Q-Switched Ruby Laser: Effective on black, blue, and green tattoos, but less so on red and yellow tattoos.
2. Q-Switched Alexandrite Laser: Better at removing black, blue, and most green tattoos but less effective on red and yellow tattoos.
3. Q-Switched NdLaser: Effective on black, blue, and green tattoos but not on yellow, white, and red tattoos.
4. Q-Switched Frequency-Doubled NdLaser: Best for removing red tattoos but prone to causing purpura and hypopigmentation.

(2) Super-Pulsed CO2 Laser

1. Introduction: Emits continuous and pulse waves, vaporizing superficial tissue and pigment, and is mostly used for treating traumatic tattoos with larger particles.
2. Treatment: Overlapping light spots by 10% is appropriate. Mild edema and congestion may occur post-surgery, subsiding in 1-5 days. Apply antibiotic ointment and avoid water scrubbing during the healing period.

(3) Adverse Reactions Post-Treatment

1. Pigmentation: More likely in certain skin types, usually subsiding in 6-9 months.
2. Hypopigmentation: Common after ruby laser treatment but usually temporary.
3. Scarring: May occur with high energy or infection.
4. Tattoo Color Change: Irrecoverable color changes can occur after laser treatment.
5. Allergic Reactions: Systemic allergic reactions, including anaphylactic shock, can occur, requiring corticosteroids.
6. Other Reactions: Temporary loss of eyebrows or whitening in the eyebrow tattoo area.

(4) Factors Affecting Therapeutic Efficacy

1. Nature and Age of Tattoo: Professional tattoos are harder to remove.
2. Tattoo Color: Red, yellow, and green tattoos are harder to treat.
3. Pigment Composition: Complex pigments react differently to lasers.
4. Pigment Density: More treatments are required for dense tattoos.
5. Pigment Size: Larger pigment particles are harder to remove.
6. Depth of Pigment: Deeper pigment particles require multiple treatments.
7. Laser Treatment Parameters: Appropriate laser selection is crucial for effective treatment.