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Managing Remaining Marks — 4.1 PIH, PIE, Atrophic, & Hypertrophic

When large, painful acne like nodules or cysts develop, you might be recommended an "acne intralesional injection" (often referred to as an intralesional steroid injection). However, many people hesitate at the word "steroid." You might worry about scary side effects, or feel like you'll have to keep getting them forever once you start. In reality, this injection works on the same principle as quickly calming inflammation to minimize burn scars. Rather than "causing" scars, it is actually a highly effective, direct approach to "preventing" them.

When large, painful acne like nodules or cysts develop, you might be recommended an "acne intralesional injection" (often referred to as an intralesional steroid injection). However, many people hesitate at the word "steroid." You might worry about scary side effects, or feel like you'll have to keep getting them forever once you start. In reality, this injection works on the same principle as quickly calming inflammation to minimize burn scars. Rather than "causing" scars, it is actually a highly effective, direct approach to "preventing" them.

Thinking "Nodules will just go away on their own" is what makes scars worse

It's common to wait, thinking that a hard, swollen nodule will subside if you just leave it alone for a few days. However, while that nodule sits there, the dermal collagen is continuously being damaged. If it stays for over a week, a brown mark can last in that spot for more than a month, and if it exceeds two weeks, a shallow pit will begin to form.

The saying "leaving it alone without squeezing prevents scars" is only true up to the comedone and papule stages. Once you reach the nodular or cystic stage, "doing nothing and leaving it alone" is the most common path to creating deep scars.

Steroid injections for acne are very different from systemic steroids

The acne injection* used for acne nodules is a procedure where a very small amount of a medication called Triamcinolone is delivered "strictly into the lesion." It is the most commonly used corticosteroid registered with the Ministry of Food and Drug Safety, and the amount injected at one time is only about 0.05 to 0.1 mL per nodule.

This distinction is crucial because, unlike oral steroids or intravenous injections, it barely spreads throughout the body. Side effects like adrenal suppression*, immune suppression, or weight gain are clinically negligible. The drug only acts on that single, specific nodule.

* Acne Injection (Intralesional Steroid Injection): A procedure in which a diluted corticosteroid, such as Triamcinolone, is injected into a nodule or cyst in a small amount of about 0.05 to 0.1 mL. The nodule's volume and pain are usually controlled within 24 to 48 hours.

* Adrenal Suppression: A side effect where the adrenal glands produce fewer of their own hormones due to long-term systemic steroid use. This side effect is clinically rarely seen with small intralesional injections because the drug concentration in the systemic bloodstream barely rises.

It works on the same principle as minimizing burn scars

In burn medicine, the key variable that determines "whether a major scar remains" is the "depth of inflammation." The deeper it goes, the larger the area of collagen damage, which then solidifies into a scar. This is why for deep burns, a standard clinical flow of quickly using silicone gel sheets, compression therapy, and corticosteroid injections within the first few days is common. When it is deep, prompt treatment is the deciding factor in reducing scars.

Acne nodules and cysts follow the exact same principle. If deep inflammation is left alone, collagen damage progresses rapidly within a few days. Whether a single nodule is resolved in 3 days versus 10 days makes a massive difference in the final scar size. An acne injection is the fastest tool to bridge those few critical days, making it a reliable way to "prevent" scarring.

Side effects are strictly localized, and concentration is key

While systemic side effects are virtually non-existent, local side effects can occur if the concentration or frequency is incorrect. Representative examples include localized skin depression (atrophy) and lightened skin color (hypopigmentation). Both typically occur when a concentration is too high (e.g., using the original 40 mg/mL solution) or when repeated injections are given in the same spot within 4 weeks.

The general practice guidelines of the Korean Dermatological Association also emphasize this principle. It is standard to dilute the concentration to within 2.5 to 5 mg/mL. We do not rigidly force a long interval—in urgent cases, additional treatment can be administered within a few days. However, as long as injections are not repeated too frequently in the same spot at overly short intervals, depression side effects are almost never seen in clinical practice.

When to do a single treatment vs a repeated treatment

For most nodules and cysts, a single injection reduces the volume within 24 to 48 hours. If the same spot swells up again, we do not force a long interval but administer another treatment when necessary. Urgent nodules and cysts can receive additional treatment within a few days. However, it is rare to exceed 3 treatments within a single cycle.

If multiple spots break out repeatedly at the same time, acne injections alone have limitations. In such cases, we look into systemic treatments such as oral antibiotics or Isotretinoin. If you feel you 'need to keep getting injections,' it is a sign that you do not need more injections, but rather a different line of treatment entirely.

Here is a summary of the timing for each situation:

The common fear that "steroids are dangerous" applies only to systemic steroids. Acne injections delivered locally into lesions work on the same principle as minimizing burn scars—they are a direct and effective way to "prevent" scarring. If you have a nodule or cyst, please do not leave it alone for a week, and let us help you calm it down within the first few days.

Frequently Asked Questions

Q. I heard that acne injections can cause skin depressions. Is this true?

It can happen if the concentration is too high or if you receive injections too frequently in the exact same spot. When using a standard concentration (2.5 to 5 mg/mL) and keeping a 4-to-6-week interval, this is a side effect we rarely see in practice. Even if a mild depression occurs, it typically fills back in on its own within a few months.

Q. Once I get it, do I have to keep getting it forever?

Not at all. Usually, a single injection is enough for one nodule. If it recurs in the same spot, you can get another one after 4 weeks. If multiple nodules are cropping up repeatedly, it's a signal to adjust your treatment plan to oral medications (antibiotics or Isotretinoin) rather than relying on injections.

Q. Can I get an acne injection for folliculitis or simple pustules?

Simple pustules can be easily managed with hygienic extraction, so injections are not necessary. Folliculitis is typically treated with antibiotics or antifungals. Acne injections are reserved for specific areas, such as deep nodules, cysts, and hypertrophic scars.

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