Intralesional Injections (Steroids, 5-FU, etc.)

Targeted Treatment for Stubborn Skin Lesions

Intralesional injections deliver medication directly into a skin lesion rather than applying it on the surface or taking it orally. This approach places a high concentration of the active drug exactly where it is needed, which is why dermatologists use it for keloids, hypertrophic scars, cystic acne, alopecia areata, and certain inflammatory skin conditions.

At TLC Skyn in Kollam, the focus is on assessing each lesion carefully before recommending an injection plan. The humid coastal climate of Kerala can affect how scars and inflammatory conditions behave, and a personalised approach matters more than a one-size-fits-all protocol.

What Is Intralesional Injections (Steroids, 5-FU, etc.)?

An intralesional injection is the direct delivery of a therapeutic substance into a skin lesion using a fine needle. The most commonly injected medication is a corticosteroid, typically triamcinolone acetonide, which reduces inflammation, suppresses collagen production, and slows the activity of scar-forming fibroblasts.

Other drugs used intralesionally include 5-fluorouracil (5-FU), an antimetabolite that stops abnormal fibroblast division, and bleomycin, sometimes used for resistant viral warts. Methotrexate may be injected for nail psoriasis in specific cases.

People with raised keloid or hypertrophic scars, persistent acne cysts, localised patches of hair loss, granulomatous conditions like granuloma annulare, or lichenified skin disorders such as nodular prurigo may benefit from this treatment. Professional assessment is essential because the choice of drug, concentration, and injection depth depends on the lesion type, its location, and the patient’s skin characteristics. Injecting the wrong concentration into thin skin, for example, can cause avoidable side effects.

Treatment Options & Advantages

Treatment Options

Intralesional Corticosteroids (Triamcinolone Acetonide)

Triamcinolone acetonide is the traditional first-line injectable for keloids, hypertrophic scars, and inflammatory lesions. It works by reducing local inflammation and slowing collagen deposition. Concentrations typically range from 2.5 mg/mL for thinner skin to 40 mg/mL for thick, dense keloid scars. The injection is given directly into the lesion, usually every three to four weeks, with the dose adjusted based on response.

This option suits patients with raised scars, localised inflammatory plaques, cystic acne, or conditions like alopecia areata where immune activity is driving the problem.

Intralesional 5-Fluorouracil (5-FU)

5-FU is an antimetabolite that inhibits fibroblast proliferation and promotes their destruction without causing tissue necrosis. It is used off-label for keloids and hypertrophic scars, particularly when steroid-only treatment has plateaued or caused side effects. A typical approach involves injecting 5-FU alone or in combination with a lower-dose steroid.

This option is often considered for patients with darker skin tones, where steroid-induced hypopigmentation is a greater concern, or for scars that have not responded adequately to steroids alone.

Combination Therapy (5-FU with Triamcinolone Acetonide)

Combining 5-FU with triamcinolone acetonide has become increasingly common in dermatology practice. Studies comparing the two approaches show that the combination often achieves better scar flattening while allowing a lower steroid dose, which reduces the risk of skin thinning and pigment changes. The injection is typically given every three to four weeks for several sessions.

This option suits patients with thick, stubborn keloids or hypertrophic scars who want faster flattening with fewer steroid-related side effects.

Treatment Advantages

• Delivers medication directly into the lesion, achieving high local concentration while minimising systemic exposure
• Reduces scar height, firmness, itching, and tenderness in many patients with keloids and hypertrophic scars
• Combination therapy can lower the steroid dose needed, reducing risks like skin atrophy and hypopigmentation
• Useful for a range of conditions beyond scars, including cystic acne, alopecia areata, and granulomatous disorders
• Performed as an outpatient procedure with no downtime in most cases
• Allows dose and drug adjustments based on individual response at each visit

Frequently Asked Questions

What is intralesional 5-fluorouracil (5-FU) used for?

Intralesional 5-FU is used primarily for keloids and hypertrophic scars. It works by blocking the multiplication of fibroblasts, the cells that produce excess collagen in raised scars.

How many sessions of intralesional injections are typically needed?

Most keloids and hypertrophic scars require multiple sessions, often spaced three to four weeks apart. The total number varies depending on scar thickness, duration, and how the lesion responds.

For a proper assessment of your scar or skin lesion and a treatment plan tailored to your skin type, book an appointment at TLC Skyn in Kollam.