What Is an Incision and Drainage (I&D) Procedure?

An incision and drainage, commonly abbreviated as I&D, is a minor surgical procedure in which a doctor cuts into an abscess or infected fluid collection and drains the pus out. It is one of the oldest and most frequently performed procedures in medicine, used primarily for skin abscesses that will not resolve on their own because the body cannot reabsorb a walled-off pocket of infection. The concept is straightforward, but the details around pain control, wound care afterward, and when the procedure is actually necessary involve more nuance than most people expect.

Why Abscesses Need Draining

An abscess forms when your immune system walls off a bacterial infection, creating a pocket filled with dead white blood cells, bacteria, and tissue debris. That pocket is what you see as a swollen, red, painful lump under the skin. Antibiotics alone struggle to penetrate this walled-off cavity, which is why physical drainage is the primary treatment. The bacterium most often responsible, Staphylococcus aureus, deploys specific proteins that actively promote abscess formation as part of its survival strategy, making these infections particularly stubborn.¹

Not every red, swollen area on the skin is an abscess. Cellulitis, for instance, is a spreading skin infection without a drainable pocket of pus. The distinction matters because cutting into cellulitis accomplishes nothing and can cause harm. When a clinician presses on the swollen area and feels a soft, fluctuant center that moves like a small water balloon under the skin, that strongly suggests a drainable collection. When the exam is ambiguous, bedside ultrasound can help distinguish the two. A meta-analysis of the available evidence found that point-of-care ultrasound was about 95% sensitive and 85% specific for identifying abscesses, and it changed the management plan in roughly one out of ten cases.²

How the Procedure Works

If you have never had an I&D, the steps are surprisingly quick. The whole thing usually takes ten to twenty minutes in a clinic or emergency department room. Here is what to expect:

Skin prep: The area around the abscess is cleaned with an antiseptic solution such as chlorhexidine or iodine. This is not a sterile procedure in the traditional surgical sense, since the act of draining infected material makes true sterility impossible, but clean technique reduces the risk of introducing new bacteria.³
Numbing: Local anesthetic is injected around the abscess to numb the skin. Sometimes a regional nerve block is used instead, especially for abscesses on the hands or feet.
The cut: Using a scalpel, the clinician makes a straight-line incision over the center of the abscess, deep enough to enter the cavity. The incision is typically two-thirds to the full diameter of the fluctuant area so there is room to work inside.³
Breaking up pockets: After pus drains out, a clamp-like instrument called a hemostat is inserted and opened at various angles inside the cavity to break apart any internal walls that might be trapping additional pus.⁴
Wound care: The wound is irrigated with saline, then either packed with gauze, left open, or managed with a drain, depending on the clinician’s judgment and the abscess size.

The incision is almost always left open rather than stitched closed, which can surprise people. Closing an infected wound traps bacteria inside and invites the abscess to reform. Healing happens from the inside out over the following days to weeks.

Does It Hurt

This is probably the most common question people have before an I&D, and the honest answer is that pain management during the procedure is a genuine clinical challenge. There is a longstanding belief among clinicians that local anesthetics work poorly in infected tissue. The theory is that the acidic environment inside an abscess partially neutralizes the numbing agent, which is a weak base. Research on this question is limited. A review in the British Journal of Anaesthesia acknowledged that local anesthesia is safe and effective in a small number of abscess drainage studies, but noted that no study has directly compared local anesthesia to general anesthesia for this procedure, and practice varies widely.⁵

In practice, many emergency departments supplement local injection with additional techniques. Some clinicians inject the anesthetic in a ring around the abscess rather than directly into the inflamed tissue, which can be more effective. Others apply topical numbing agents to the skin surface before injecting. For larger or deeper abscesses, or when patients are extremely anxious, procedural sedation with medications like ketamine or propofol may be used, though this adds complexity and monitoring requirements. The discomfort tends to be worst during the initial injection and the breaking-up of internal pockets. Once the pus is draining, most people feel immediate pressure relief.

The Packing Debate

Traditionally, after draining an abscess, clinicians would stuff the wound cavity with a long strip of gauze. The rationale was that packing kept the wound open, prevented premature skin closure, and wicked out residual pus. Patients then had to return every day or two to have the packing removed and replaced, which was often painful and inconvenient. The evidence behind this practice turns out to be surprisingly thin.

A systematic review and meta-analysis pooling data from eight randomized trials with nearly 500 patients found no significant difference in recurrence rates or need for repeat procedures between patients whose wounds were packed and those left unpacked.⁶ A focused review of smaller abscesses reached a similar conclusion: for abscesses under 5 cm, packing does not affect outcomes in otherwise healthy people.⁷ A pediatric trial found comparable failure rates whether children’s wounds were packed or left open, with no meaningful difference in pain scores either.⁸

That said, clinicians have not universally abandoned packing. The meta-analysis authors noted that the combined evidence was not large enough to be truly conclusive, and the possibility of a missed difference remains.⁶ For very large or deep cavities, many surgeons still pack, reasoning that the existing trials mostly studied smaller abscesses. If your clinician decides not to pack, current evidence supports that decision for routine abscesses.

Loop Drainage as an Alternative

A newer technique called loop drainage has gained traction, especially in emergency departments. Instead of making a single large incision and packing the wound, the clinician makes two small stab incisions on either side of the abscess and threads a thin, flexible drain (often a small rubber vessel loop or a section of a Penrose drain) through the cavity and ties the ends together in a loop. The loop keeps the cavity from closing too early and allows ongoing drainage without daily packing changes.

A randomized trial comparing loop drainage to standard I&D with packing found that loop patients reported significantly less pain at follow-up, found the wound much easier to care for over the first 36 hours, and were more satisfied at the 10-day mark. Treatment failure occurred in about 13% of loop patients compared with 20% in the packing group, though the overall difference did not reach statistical significance. In children, however, the difference was striking: zero failures in the loop group compared with 21% in the packing group.⁹

A separate pediatric study found comparable failure rates and cosmetic outcomes between loop drainage and standard I&D, with similar parent satisfaction scores at two weeks.¹⁰ These results, along with needle aspiration and catheter-based approaches, have broadened the menu of options beyond the traditional single-incision technique.¹¹ If you are facing an I&D, asking your clinician whether loop drainage is appropriate for your abscess is a reasonable conversation to have.

Do You Need Antibiotics Afterward

Many people assume they will leave with a prescription for antibiotics after an I&D. For straightforward skin abscesses in otherwise healthy people, that is often unnecessary. A meta-analysis looking at antibiotics given after drainage found no significant improvement in complete healing at 7 to 10 days: about 88% of patients healed with antibiotics compared with 86% without.¹² The drainage itself removes the bulk of the infection, and the body can handle the rest.

Antibiotics do play a role in specific situations. Clinicians are more likely to prescribe them when there is surrounding cellulitis extending well beyond the abscess margins, when the patient has a weakened immune system, when there are signs of systemic illness like fever, or when the infection involves a high-risk location. Guidelines for healthy patients with uncomplicated abscesses generally recommend I&D alone, without routine wound cultures or blood tests.¹³ If you are prescribed antibiotics after drainage, your clinician likely sees a reason beyond the abscess itself.

Locations That Require Extra Caution

Most skin abscesses show up in predictable spots: the armpit, groin, buttocks, and inner thighs, all areas with friction, sweat, and hair follicles. These are generally straightforward to drain. But abscesses in certain anatomic locations require specialized evaluation and sometimes referral to a surgeon or specialist.¹⁴

Perianal and perirectal abscesses sit near the anal canal and can communicate with deeper tissue planes or form fistula tracts. These often need drainage in an operating room under sedation rather than at the bedside. Abscesses on the face, particularly in the area between the nose and the upper lip (sometimes called the “danger triangle”), carry a small risk of spreading infection toward the brain via valveless veins. Breast abscesses in lactating women require careful drainage that preserves milk ducts. Hand abscesses, especially around the fingertips or in the deep spaces of the palm, can threaten tendons and require a hand surgeon. None of these are reasons to delay care, but they are reasons your emergency physician might call in a consultant rather than proceeding immediately.

I&D for Children

Children get skin abscesses frequently, and the procedure is fundamentally the same as in adults, but managing pain and anxiety in a young child adds a layer of complexity. A large multicenter study of over 6,300 pediatric I&D procedures found that procedural sedation was used in about 24% of cases, with enormous variation between hospitals ranging from 2% to 94%.¹⁵ Ketamine was the most commonly used sedation agent, given to about 69% of sedated children.

That wide variation suggests there is no clear consensus on when sedation is warranted. Younger children and those with abscesses in sensitive body sites were more likely to receive sedation. Troublingly, the study also found that African American children and those without employer-based insurance were less likely to receive sedation even after adjusting for clinical factors, pointing to disparities in pain management that extend beyond the medical question of what works best.¹⁵ If your child needs an I&D, asking about sedation options and pain management is worth the conversation, particularly for anxious or very young children.

Pilonidal Abscesses

Pilonidal abscesses deserve a separate mention because they are common in young adults, notoriously prone to coming back, and managed somewhat differently from a typical skin abscess. These form at the base of the tailbone, usually due to ingrown hairs, and can become acutely painful and swollen. The initial treatment is usually a simple I&D performed under local anesthesia. In a study of 73 patients with a first-episode acute pilonidal abscess, I&D relieved symptoms in all cases, and patients returned to work immediately after treatment. About 58% healed within 10 weeks without further surgery.¹⁶

The catch is the recurrence rate. In a larger long-term study of 583 patients, performing an initial I&D before definitive surgery was associated with a 20-year recurrence rate of 24%, compared with 35% in patients who went straight to definitive surgery without a preceding I&D.¹⁷ The initial drainage appears to reduce inflammation and create better conditions for the later, more definitive operation. If you develop a pilonidal abscess, expect the first visit to provide relief through I&D, with a conversation about longer-term surgical options once things have calmed down.

Hidradenitis Suppurativa

People with hidradenitis suppurativa (HS), a chronic inflammatory condition that causes recurring painful lumps in the armpits, groin, and other skin-fold areas, often undergo repeated I&D procedures for flare-ups. Drainage provides short-term symptom relief, but because HS is driven by chronic inflammation rather than a single infection, I&D does not address the underlying disease. Surgical management reviews note that while I&D is commonly used for acute flares, curative surgical data remain limited, and favorable outcomes from more extensive surgical approaches tend to occur in carefully selected patients.¹⁸ If you find yourself needing I&D more than once or twice in the same area, it is worth discussing with a dermatologist whether a broader treatment plan for HS might be appropriate.

What Recovery Looks Like

After an I&D, the wound is left open and will look like a small, gaping cut. This is intentional. You will likely be instructed to keep the area clean, change dressings daily, and watch for signs that the infection is worsening: increasing redness, swelling, warmth, fever, or red streaking spreading away from the wound. Most simple abscesses heal within two to four weeks, though larger ones can take longer.

Follow-up visits vary. If your wound was packed, you will probably need to return within 48 hours to have the packing removed or replaced. If it was left open without packing, you may only need to follow up if things are not improving. Warm compresses or soaks can help keep the wound draining and promote healing. Avoid submerging the wound in pools or baths until it has closed.

Recurrence is the most common frustration. Abscesses can return in the same spot if the underlying cause, such as a chronically blocked hair follicle or a skin-fold friction point, is not addressed. If an abscess comes back more than once, your clinician may recommend wound cultures to identify the specific bacterium involved, check for risk factors you may not have considered, or refer you for imaging to rule out a deeper source.

When Ultrasound Changes the Plan

Bedside ultrasound has become a valuable tool in the evaluation step before I&D. Emergency physicians increasingly use a handheld probe to visualize what is happening beneath the skin before picking up a scalpel. A systematic review found that ultrasound helped physicians correctly distinguish abscesses from cellulitis and led to a change in clinical management, such as deciding to drain when drainage was not initially planned, or deciding not to drain when no fluid collection was found, in about 10% of cases.² Ultrasound is also useful for locating the abscess cavity precisely, which can guide where to make the incision and help avoid unnecessary tissue disruption. Earlier reviews supported the same finding: when physical examination alone is ambiguous, ultrasound adds diagnostic clarity.¹⁹

You are most likely to encounter ultrasound use in an emergency department or urgent care setting staffed by physicians trained in point-of-care imaging. If your lump is deep, in an unusual location, or does not clearly feel like a classic abscess on exam, ultrasound before the procedure can save you from either an unnecessary incision or a missed collection.

1
Europe PMC. A play in four acts: Staphylococcus aureus abscess formation
2
PubMed. Point-of-Care Ultrasonography for the Diagnosis of Skin and Soft Tissue Abscesses: A Systematic Review and Meta-analysis
3
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4
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5
British Journal of Anaesthesia. Anaesthetic management of subcutaneous abscesses: current status
6
PubMed. Incision and drainage of cutaneous abscess with or without cavity packing: a systematic review, meta-analysis, and trial sequential analysis of randomised controlled trials
7
PubMed Central. Packing versus non-packing outcomes for abscesses after incision and drainage
8
Pediatric Emergency Care. Randomized Trial Comparing Wound Packing to No Wound Packing Following Incision and Drainage of Superficial Skin Abscesses in the Pediatric Emergency Department
9
PubMed. A Randomized Controlled Trial of Novel Loop Drainage Technique Versus Standard Incision and Drainage in the Treatment of Skin Abscesses
10
Pediatric Emergency Care. Comparison of Minimally Invasive Loop Drainage and Standard Incision and Drainage of Cutaneous Abscesses in Children Presenting to a Pediatric Emergency Department
11
Hindawi / Nursing Research and Practice. Purulent Skin and Soft Tissue Infections, Challenging the Practice of Incision and Drainage: A Scoping Review
12
Emergency Medicine Journal. Systemic antibiotics after incision and drainage of simple abscesses: a meta-analysis
13
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14
PubMed. Abscess incision and drainage in the emergency department–Part I
15
PubMed Central. Variation in the Use of Procedural Sedation for Incision and Drainage of Skin and Soft Tissue Infection in Pediatric Emergency Departments
16
British Journal of Surgery. Prognosis after simple incision and drainage for a first-episode acute pilonidal abscess
17
PubMed. Incision and drainage preceding definite surgery achieves lower 20-year long-term recurrence rate in 583 primary pilonidal sinus surgery patients
18
Europe PMC. Surgical Management of Hidradenitis Suppurativa: A Narrative Review
19
PubMed. Point-of-care Ultrasound for Diagnosis of Abscess in Skin and Soft Tissue Infections