Chapter 111. Sebaceous Cyst Incision and Drainage

Sebaceous cysts are common, present with a very benign evolution, may be located anywhere on the body, and frequently become infected. They are most commonly found on the face, neck, and trunk. Sebaceous cysts are usually asymptomatic unless they become infected. The Emergency Physician must be acquainted with the principles involved in treating infected sebaceous cysts, particularly if they are located on cosmetically important areas such as the face.

Sebaceous cysts are the result of obstruction of sebaceous gland ducts. They are freely mobile, slow growing, round shaped, painless, and located in the subcutaneous tissues. The cysts are made of a thin white capsule filled with a thick, cheesy, and keratinous material. Their size is variable and ranges from less than a quarter of an inch to more than 2 inches. These keratin-containing lesions are usually seen in young and middle-aged adults in relation to a pilosebaceous follicle.1 Sebaceous cysts may be present for many years before infection occurs. Physical examination often reveals a subcutaneous mass that is fluctuant and tender. The overlying skin may appear normal or erythematous.

The initial treatment of choice of an infected sebaceous cyst is incision and drainage. The sebaceous material is too thick to allow for spontaneous drainage and it must be expressed. The sebaceous cyst will likely recur, however, unless the capsule of the cyst is removed. Patients may have the initial incision and drainage performed in the Emergency Department with follow-up at some later date to remove the cyst capsule. Alternatively, the cyst capsule may be removed at the time of the initial incision and drainage.

Incision and drainage in the Emergency Department is indicated whenever a patient presents with a tender sebaceous cyst consistent with an abscess. The procedure will relieve the patient's pain. Antibiotics without drainage are ineffective in treating abscesses.2 The vast majority of infected sebaceous cysts may be drained in the Emergency Department, clinic, or office setting. A noninfected sebaceous cyst may be removed electively and for cosmetic purposes in the clinic or office setting by a Primary Care Provider or a Surgeon.

There are no absolute contraindications to the incision and drainage or removal of an infected sebaceous cyst. Caution is advised in those patients with bleeding disorders, taking anticoagulants, or with thrombocytopenia. Incision and drainage is preferred if the overlying skin is cellulitic. The capsule can be removed at a later time. Extremely large abscesses or those in which adequate anesthesia is not possible should be managed in the Operating Room by a General Surgeon or Plastic Surgeon. The procedure should be conducted under general anesthesia in the Operating Room if adequate anesthesia cannot be obtained and pain limits the procedure. Refer patients with noninfected sebaceous cysts to their Primary Care Physician, a General Surgeon, or a Plastic Surgeon for removal.

• Gown, face mask, and gloves
• Povidone iodine or chlorhexidine solution
• 10 mL syringe
• 25 or 27 gauge needle, 2 in. long
• Local anesthetic solution, with or without epinephrine
• #11 scalpel blade on a handle
• #15 scalpel blade on a handle
• Curved hemostat
• Iris scissors
• Ribbon gauze, plain or iodinated
• 2 × 2 gauze squares
• Adhesive tape
• Sterile saline
• Nylon sutures for skin closure, various sizes
• 3-0 Vicryl suture
• Needle driver

Explain and document the risks, benefits, and potential complications of the procedure to the patient and/or their representative. The postprocedure care should be explained as well. Obtain an informed consent for the procedure. Obtain an additional informed consent for the procedural sedation or nitrous oxide procedure if it applies. Wear a face mask, gown, and gloves for the entire procedure. The injection of local anesthetic solution can force abscess contents to shoot out. Incision of a tense abscess can also result in contamination.

Antibiotic resistance is a growing concern. The incision and drainage of a simple and noncomplicated skin abscess does not require antibiotic therapy.3,4 The incision and drainage procedure may release bacteria into the circulation. Consider the use of preprocedural intravenous antibiotics in those patients suspected or known to be immunocompromised, a history of prosthetic heart valve replacement, a history of artificial joint replacement, or signs of systemic toxicity.

Clean any dirt and debris from the skin overlying the abscess or cyst. Apply povidone iodine or chlorhexidine solution and allow it to dry. Apply drapes to delineate a procedural field and absorb any material or blood that escapes from the abscess cavity.

Anesthesia

Recognizing that it is often difficult to obtain, local anesthesia should be considered the first choice. Direct infiltration of the skin and soft tissues in a fan-like pattern surrounding an abscess or “field block” provides sufficient anesthesia to tolerate the procedure (Figures 111-1A & B).5 Local anesthetics are weak acids and less effective in the acidic environment of an abscess and should not be directly injected in the abscess cavity. The pain caused by injection of the local anesthetic solution is related to the rate that the anesthetic is injected and the force necessary to inject it. Inject the local anesthetic solution slowly through a small-bore needle (25 to 30 gauge) as the needle is withdrawn through the dermis. The needle bore will create a passage through the subcutaneous tissue as it is inserted that enables the local anesthetic solution to be infiltrated slowly and with less discomfort.

Hold the syringe horizontally in reference to the skin surface. Inject 3 to 4 mL of local anesthetic solution intradermally over the dome of the abscess (Figure 111-2). The skin will blanch if the injection is given properly. The increased pressure within the cavity will cause more discomfort to the patient and may cause the solution to be forcefully expelled if there is an opening in the skin therefore some practitioners prefer to skip this step. Alternative anesthesia could be accomplished with regional or individual nerve blocks when the abscess is located in an anatomical area of innervation.

Systemic analgesia (i.e., procedural sedation) is strongly recommended in the pediatric population, it may occasionally be required as well in adults when a field anesthesia has suboptimal results. In rare occasions, the procedure should be conducted under general anesthesia in the Operating Room if adequate anesthesia cannot be obtained and pain limits the procedure.

Incision and Drainage

Make a stab incision with a #11 scalpel blade in the skin overlying the area of fluctuance (Figure 111-3A). The incision should be parallel to any lines of tension to produce the least conspicuous scar, particularly in cosmetically important areas such as the face. Extend the incision the length of the fluctuant area with a #11 or #15 scalpel blade unless the abscess is in a cosmetically important area. A linear incision is adequate, although some advocate a cruciate incision (Figure 110-10). The cruciate incision results in greater scarring, however, and probably is not necessary. An elliptical incision can be performed in noncosmetically important areas (Figure 111-3B). The purpose of the elliptical incision is to remove a full thickness wedge of tissue so that the wound will remain open. Limit the length of the incision on cosmetically important areas to 3 to 4 mm. This is just large enough to drain the abscess.

Express the pus and the sebaceous material. It is too thick to drain spontaneously. It is important that loculations be lysed and the area be thoroughly drained to minimize recurrence. Insert a hemostat and spread the jaws within the cavity (Figure 111-3C). Useful technique employs gauze clamped in the jaws of a hemostat and swirled inside the abscess cavity to break adhesions and remove debris. Irrigate the cavity with normal saline (Figure 111-3C).

Loosely pack the wound cavity with ribbon gauze or gauze squares to prevent the skin edges from closing prematurely if a linear incision was made (Figure 111-3D). Cruciate and elliptical incisions do not require packing of the wound. Cover the wound with a bulky gauze dressing to soak up continued drainage.

Incision and Drainage with Primary Cyst Removal

The entire sebaceous cyst, including the capsule, can be removed at the time of the incision and drainage with a simplified technique.6 Make an incision in the skin overlying the center of the sebaceous cyst. Extend the incision to be slightly longer than the diameter of the sebaceous cyst. Do not cut into the dermis or subcutaneous tissues. Sharply dissect the sebaceous cyst free of the surrounding subcutaneous tissues with an iris scissors. The delineation between the thin, shiny, white capsule and the surrounding tissues is very obvious. Do not puncture the capsule of the sebaceous cyst. Doing so and spilling some of the contents sets up a nidus for subsequent infection or reformation of the sebaceous cyst. Start at both ends of the incision and free the cyst circumferentially. Once the sides of the cyst are free from the surrounding adipose tissue, gently grasp the top of the cyst with a hemostat or forceps and gently elevate it. Dissect the inferior border of the cyst free until it can be removed. Irrigate the wound with at least 200 mL of normal saline solution. Allow the cavity to heal by granulation. Alternatively, close the pocket with 3-0 Vicryl deep sutures and approximate the skin edges with nylon sutures.

The cyst capsule can often rupture when attempting to remove it intact. If this occurs, express the contents as if incising and draining an abscess. Gently flush the cyst cavity with normal saline. Grasp the shiny, cut edges of the capsule with a hemostat. Gently elevate the cyst capsule edges and dissect the complete cyst capsule free from the surrounding adipose tissue. Irrigate the wound with at least 200 mL of normal saline solution. Allow the cavity to heal by granulation. Alternatively, close the pocket with 3-0 Vicryl deep sutures and approximate the skin edges with nylon sutures.

Submit the complete cyst and capsule or the ruptured capsule for pathologic diagnosis in a sterile container. Several pathologic conditions can mimic a sebaceous cyst. This includes adenomas, adenocarcinomas, dermoids in children, and melanomas. Preauricular tender masses can be parotid gland tumors.

This technique results in fewer days to heal, less pain for the patient, and less scarring than with incision and drainage alone.6 This was not a blinded study and no other studies could be found to verify their results. The researchers noted that primary resection (average of 50 minutes) takes longer than simple incision and drainage (average of 10 minutes). This may limit its use in the Emergency Department.

Antibiotics are generally unnecessary to treat a simple abscess unless there is cellulitis of the skin surrounding the wound.2 No data could be found regarding patients with an abscess who are diabetic, have cardiac valve disease, who have hardware in their body, or who are immunocompromised. These patients are at risk for infectious complications. It is advised to cover these patients with antibiotics. Likewise, there is no data on the optimal duration of antibiotic treatment. The conventional 7 to 10 day course of antibiotic coverage is probably adequate.

Bacteriology of cutaneous abscesses remote from the rectum usually show aerobic skin flora, with Staphylococcus and Streptococcus being the most common etiologies.4 Antibiotics recommended are a first-generation cephalosporin, a penicillinase-resistant penicillin, or a newer fluoroquinolone. Prescribe clindamycin, doxycycline, or trimethoprim-sulfamethoxazole if methicillin-resistant Staphylococcus aureus is suspected as the etiology.7

Instruct the patient to change the gauze dressing as often as necessary to keep the outside of the dressing dry. Patients should have scheduled follow-up in 48 hours for a wound check and removal of the packing. The packing should be removed in 24 hours if the wound is on the face. If the wound is large, reinsert the packing upon follow-up. Incisions that remain open or that have an elliptical or cruciate incision do not require packing. Advise the patient to change the packing every 24 to 48 hours, depending on the amount of drainage. Decrease the amount of packing each time to allow the wound to heal from the base outward. The patient should thoroughly wash the wound with soap and water in the shower each time the packing is removed. It is helpful to let the stream of shower water run inside the wound to aid in wound irrigation. Discontinue the packing once the wound is well granulated and there is no concern that the skin edges will adhere to each other. The patient must continue to clean the wound thoroughly every day until it is fully healed.

Healing may take one to several weeks depending upon the size of the abscess cavity, the patient's age, and any comorbidities. Instruct the patient to return to the Emergency Department immediately if they develop a fever, increased pain, or worsening redness of the skin surrounding the abscess. Pain relief can be provided with nonsteroidal anti-inflammatory drugs. Occasionally, narcotic analgesics may be required in the first 24 hours after the procedure.

Inform the patient that incision and drainage in the acute care setting is not definitive treatment and that the condition is likely to recur unless the cyst is removed. Refer the patient to a physician who can provide wound care as well as remove the cyst capsule.

Sebaceous cyst infections may spread if the wound is inadequately drained. Attention must be paid to underlying anatomical structures, such as cranial nerve VII, when draining facial abscesses to avoid complications caused by inadvertently incising these structures. Incomplete removal of the cyst wall or spillage of the cyst contents sets up a nidus for future infection and/or recurrence of the sebaceous cyst. A linear incision or too small of an incision can result in premature skin closure, incomplete healing of the cavity, and recurrence. Too large of an incision can result in delayed healing and significant scarring. Postprocedural bleeding is rare.

Infected sebaceous cysts are commonly seen in the Emergency Department. They are thought to be due to blockage of the ducts of sebaceous glands that subsequently become infected and form an abscess. Most cutaneous abscesses can be drained in the Emergency Department. Consult a Surgeon for those patients with large abscesses who require drainage in the Operating Room. Patients with signs of fever or toxicity should be admitted for parenteral antibiotics, incision and drainage, and observation. Refer patients to a physician who can provide wound care as well as definitive excision of the sebaceous cyst.