This document provides guidance on diagnosing and treating cutaneous abscesses and pustules. A cutaneous abscess typically presents as a localized, warm, swollen, and red area of skin that is painful and fluctuant to the touch, sometimes with surrounding cellulitis. Treatment involves draining the pus by incising the skin over the abscess after numbing the area with local anesthetic. The cavity should be cleaned and loosely packed to allow for drainage. Incision and drainage is usually sufficient treatment without the need for antibiotics, unless the patient is immunocompromised or systemically unwell.

1. Cutaneous Abscess or Pustule
Presentation
With or without a history of minor trauma (such as an embedded foreign body) the
patient has localized pain, swelling and redness of the skin. The area is warm, firm,
and, usually fluctuant to palpation. There is sometimes surrounding cellulitis or
lymphangitis and, in the more serious case, fever. There may be an spot where the
abscess is close to the skin, the skin is thinned, and pus may break through to drain
spontaneously ("pointing"). A pustule will appear only as a cloudy tender vesicle
surrounded by some redness and induration, and occasionally will be the source of an
ascending lymphangitis.
What to do:
• A pustule may not require any anesthesia for drainage. Simply snip open the
cutaneous roof with fine scissors or an inverted #11 blade, grasp an edge with
pickups and excise the entire overlying surface. Cleanse the open surface with
normal saline and cover it with povidone- iodine ointment and a dressing.
• When the location of an abscess cavity is uncertain, attempt to aspirate it with a
# 18 gauge needle after prepping the area with povidone-iodine. If an abscess
cavity cannot be located, send the patient out on antibiotics and intermittent
warm moist compresses and have him seen again in 24 hours.
• When the abscess is pointing or has been located by needle aspiration, prepare
the overlying skin for incision and drainage with povidone-iodine solution.
Anesthetize the area with regional field block, accomplished by injecting a ring of
subcutaneous 1% lidocaine solution approximately l cm away from the
erythematous border of the abscess. In addition, inject lidocaine into the roof of
the abscess along the line of the projected incision.
• The incision should be made with a #11 or #15 blade at the most dependent
area of fluctuance. It should be large and directed along the relaxed skin tension
lines to reduce future scarring
• In larger abscesses insert a hemostat into the cavity to break up any loculated
collections of pus. The cavity may then be irrigated with normal saline and
loosely packed with Iodoform or plain gauze. Leave a small wick of this gauze
protruding through the incision to allow for continued drainage and easy removal
after 48 hours.
• The patient should be instructed to use intermittent warm water soaks or
compresses for a few days when there is no packing used or after packing is
removed.
• A dressing should be provided to collect continued drainage.

2. What not to do:
• Do not incise an abscess that lies in close proximity to a major vessel, such as in
the axilla, groin or antecubital space, without first confirming its location and
nature by needle aspiration.
• Do not treat deep infections of the hands as simple cutaneous abscesses. When
significant pain and swelling exists, or there is pain or range of motion of a
finger, seek surgical consultation
Discussion
Either trauma or obstruction of glands in the skin can lead to cutaneous abscesses.
Incision and drainage is the definitive therapy for these lesions and, therefore, routine
cultures and antibiotics are generally not indicated. Exceptions exist in the
immunologically suppressed patient, the toxic, febrile patient, or where there is a large
area of cellulitis or lymphangitis, in which cases an antibiotic can be selected on the
basis of a Gram stain or presumptively based on body location.
It is sometimes not possible to achieve total regional anesthesia for incision and
drainage of an abscess, perhaps because local tissue acidosis neutralizes local
anesthetics. In such cases, additional analgesia may be obtained by premedication with
narcotics or brief inhalation of nitrous oxide.