The Bottom Line

Surgical site infections (SSIs) after dermatologic surgery are uncommon — occurring in just 1-3% of clean procedures — but recognizing the signs early is crucial for effective treatment. The key warning signs are increasing redness, swelling, warmth, pain, and pus drainage appearing 3-10 days after surgery. Prompt treatment with antibiotics and wound care almost always resolves the infection successfully.

What Is a Surgical Site Infection?

A surgical site infection is a bacterial infection that develops at the location of your skin surgery within 30 days of the procedure. Bacteria — most commonly Staphylococcus aureus (staph) and Streptococcus (strep) — enter the wound during or after surgery and multiply in the healing tissue. SSIs are classified by depth: superficial infections involve only the skin and subcutaneous tissue above the sutures, while deep infections penetrate below the surgical closure into deeper tissue layers.

After dermatologic surgery (excisions, Mohs surgery, biopsies, skin flaps), SSI rates are low — typically 1-3% for clean procedures. Rates are higher for surgery below the knee (up to 7%), in the groin or perineal area (up to 10%), and in patients with diabetes or immunosuppression. Most SSIs are superficial and respond well to antibiotics when caught early.

Signs and Symptoms: How to Recognize a Surgical Site Infection

It's normal for a surgical wound to have some redness, swelling, and tenderness for the first 2-3 days — this is part of normal healing inflammation. A surgical site infection looks different because symptoms appear or worsen after the initial healing inflammation should be improving (typically day 3-10 post-surgery).

Classic signs of infection (remember "SHARP"):

  • S — Swelling that increases after day 3 rather than decreasing
  • H — Heat — the wound area feels warm or hot to the touch
  • A — Advancing redness — redness that spreads outward from the wound edges (unlike normal post-surgical redness which stays close to the incision and fades)
  • R — Redness with red streaking — red lines extending away from the wound toward lymph nodes indicate spreading infection (cellulitis/lymphangitis)
  • P — Purulent drainage — thick, cloudy, yellow/green, or foul-smelling fluid from the wound (pus)

Additional signs: Fever above 100.4°F (38°C), increasing pain after pain had been improving, wound edges separating (infection can cause dehiscence), and general malaise or feeling unwell.

What is NOT typically infection: Light pink color around sutures, clear or light blood-tinged drainage, mild tenderness when you accidentally bump the wound, and suture knot reactions (small red bumps directly at suture entry points).

What Causes Surgical Site Infections?

Bacteria are everywhere on the skin's surface, and despite sterile surgical technique, some can enter the wound. Whether an infection develops depends on the balance between bacterial load and your immune defenses:

Patient risk factors:

  • Diabetes: Elevated blood sugar impairs white blood cell function — the cells that fight infection
  • Smoking: Reduces blood flow and oxygen delivery to the wound, creating a favorable environment for bacteria
  • Immunosuppression: Medications like prednisone, methotrexate, or biologic drugs suppress immune defenses
  • Obesity: Fatty tissue has poor blood supply and harbors more bacteria
  • Older age: Immune function naturally declines with age

Surgical factors: Longer procedures, surgery on the lower extremities (poor circulation), contaminated wounds (surgery involving infected cysts or abscesses), and procedures near the nose or mouth (higher bacterial counts in these areas).

Post-surgical factors: Touching the wound with unwashed hands, getting the wound dirty or submerged in water too early, removing dressings prematurely, and not following wound care instructions.

Treatment Options for Surgical Site Infections

Mild superficial infection (most common):

  • Oral antibiotics — typically cephalexin (Keflex) or dicloxacillin for 7-10 days. If MRSA is suspected, trimethoprim-sulfamethoxazole (Bactrim) or doxycycline may be used.
  • Topical wound care — gentle cleansing with saline or dilute hydrogen peroxide, followed by application of mupirocin ointment
  • Continued wound monitoring — your surgeon will likely want to see you for a wound check within 48-72 hours of starting antibiotics

Moderate infection with abscess formation:

  • Incision and drainage — your surgeon opens a portion of the wound to release pus and infected fluid. This provides immediate relief and is essential for healing because antibiotics alone cannot penetrate an enclosed abscess.
  • Wound packing — the drained cavity is often packed with gauze that is changed daily, allowing the wound to heal from the inside out
  • Oral antibiotics are prescribed in conjunction

Severe or spreading infection (rare):

  • IV antibiotics in a hospital setting if the infection involves cellulitis spreading rapidly, or if the patient is immunocompromised or systemically ill
  • Wound cultures to identify the specific bacteria and ensure appropriate antibiotic coverage

When to See a Dermatologist

Contact your surgeon the same day if you notice increasing redness that extends more than 1 centimeter from the wound edge, pus or foul-smelling drainage from the wound, increasing pain and swelling after day 3, or a fever above 100.4°F. Seek emergency care if you see red streaking extending from the wound toward your armpit, groin, or neck (lymphangitis), have a high fever with chills and feeling very unwell, or the wound area becomes rapidly red, swollen, and extremely painful — which could indicate a serious infection requiring immediate treatment.

Frequently Asked Questions

How can I reduce my risk of infection after skin surgery?

Follow your surgeon's wound care instructions precisely: keep the wound covered and dry for the recommended period, clean gently with the prescribed solution, apply any topical antibiotic as directed, wash your hands before touching the wound area, and avoid submerging the wound in baths, pools, or hot tubs until cleared. If you smoke, stopping for at least 2-4 weeks before and after surgery significantly reduces infection risk.

Is it normal for my wound to be red after surgery?

Yes — mild redness immediately around the incision line is normal for the first 2-3 days and is part of the healing inflammatory response. The key difference is the trajectory: normal healing redness stays close to the wound and gradually fades, while infection redness spreads outward, intensifies after day 3, and is accompanied by warmth, swelling, and drainage.

Should I use Neosporin or antibiotic ointment on my wound?

Follow your surgeon's specific recommendation. Many dermatologists prefer plain petrolatum (Vaseline) over Neosporin because allergic reactions to neomycin (an ingredient in Neosporin) are common — up to 10% of patients — and can mimic infection with redness and weeping. Petrolatum keeps the wound moist for optimal healing without allergy risk. Mupirocin (Bactrim ointment) may be prescribed for higher-risk wounds.

Can I take a shower after skin surgery?

Most surgeons allow gentle showering 24-48 hours after surgery — letting water briefly run over the wound is generally safe. However, avoid soaking the wound, directing strong water pressure at it, or submerging it in a bath, pool, or ocean until your surgeon gives clearance (typically 2-4 weeks). Pat the area dry gently and reapply your dressing.

References

  1. Heal CF, Buettner PG, Cruickshank R, et al. Does single application of topical chloramphenicol to high-risk sutured wounds reduce incidence of wound infection? BMJ. 2009;338:a2812.
  2. Dixon AJ, Dixon MP, Askew DA, et al. Prospective study of wound infections in dermatologic surgery. Dermatol Surg. 2006;32(6):819-826.
  3. Maragh SL, Brown MD. Prospective evaluation of surgical site infection rate among patients with Mohs micrographic surgery. Dermatol Surg. 2008;34(2):164-167.
  4. Rosengren H, Dixon A. Antibacterial prophylaxis in dermatologic surgery: an evidence-based review. Am J Clin Dermatol. 2010;11(1):35-44.

Trusted Resources

  • American Academy of Dermatology Association. "Wound Care." aad.org
  • Centers for Disease Control and Prevention. "Surgical Site Infection." cdc.gov
  • Mayo Clinic. "Surgical Wound Infection." mayoclinic.org

Early recognition of infection signs and prompt treatment lead to the best outcomes. When in doubt, contact your surgeon.