Recurrent Cellulitis Caused by a Hidden Abscess: A Case Report

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Skin and soft tissue infections are common conditions that occur in inpatient and outpatient settings. The most common factor leading to the development of skin and soft tissue infections is a breach of the skin barrier. Various conditions can be categorized by the depth and extent of skin involvement. Deeper-layer involvement is seen in cellulitis and abscesses. These conditions require adequate management strategies, such as prompt initiation of antibiotics as well as incision and drainage when indicated.¹

Cellulitis is a common inflammatory disease that affects the deeper dermis and subcutaneous fat layer. It is characterized by symptoms such as erythema, tenderness, edema, and fever. Prodromal signs are rare, with the development of painful erythematous indurated lesions with rapidly spreading heat and no identifiable borders. These lesions may initially form surface blisters before necrosis occurs. Cellulitis typically occurs in men and often affects the upper and lower extremities. Antibiotics alone may be sufficient to treat cellulitis, but if the infection progresses to abscess or necrosis, surgical intervention is required.^1,2

An abscess is a localized collection of pus within the subcutaneous tissue. Common causes of abscesses are bacterial infections such as group A streptococci (Streptococcus pyogenes) and Staphylococcus aureus.³ The overlying epidermis may obstruct drainage, leading to the development of an abscess. Incision and drainage may be the primary and definitive treatment for an abscess.

The subject of this case report is a 65-year-old male who underwent 5 incision and drainage procedures over an 8-month period at 2 different hospitals in an unsuccessful attempt to resolve cellulitis. The patient was healed at Kangwon National University Hospital, Chuncheon, Republic of Korea, after the authors of the current report identified and removed a hidden abscess pocket. 

A 65-year-old male with hypertension and diabetes was admitted to the hospital for treatment of refractory cellulitis despite 8 months of aggressive treatments. Ten months prior to this latest admission, an erythematous induration of unknown origin appeared on his left buttock; the lesion was initially approximately 5 cm × 5 cm, but it was left untreated. After 2 months, the lesion developed into an 18-cm × 15-cm inflammatory lesion with symptoms of blistering and rupture. The patient received antibiotic medication and underwent 3 incision and drainage procedures at another clinic, as well as 2 more incision and drainage procedures at another general hospital over a period of 8 months. Despite multiple attempts at management, the lesion recurred, and symptoms showed no signs of improvement. 

The patient was transferred to the hospital of the authors of the current report due to persistent pain and oozing. Systemic reviews, blood tests, electrocardiogram, and chest X-ray revealed no fever or constitutional symptoms. Physical examinations showed chronic inflammation with exudates in his left buttock. Pain was elicited on palpation, and the skin and subcutaneous tissue showed diffuse induration and discoloration. Openings from several previous surgeries, each surrounded by a rim of erythematous swelling, were observed (Figure 1).

Even with careful palpation and probing through the opening, no fistula or abscess pocket was found. Blood tests showed that the white blood cell count (7800/µL) and C-reactive protein level (0.232 mg/dL) were within normal limits. The creatine kinase level was also within normal limits. Enhanced CT of the lower extremities was performed to determine the extent of inflammation, and to evaluate for necrotizing soft tissue infections and any underlying skeletal abnormalities. CT revealed an ill-defined, heterogeneously enhancing lesion involving the skin and subcutaneous layer of the left buttock and posterior thigh. An abscess was suspected, with a fistula extending to the outside of the buttock (Figure 2). 

Empirical intravenous antibacterial therapy was initiated with amoxicillin 1 g/clavulanate 0.2 g every 8 hours for 7 days, and debridement of devitalized tissue was performed under general anesthesia on the first day of admission. Using a No. 10 surgical blade and a curette, unhealthy skin and subcutaneous tissues were removed until healthy tissue was reached. After removal of the overlying necrotic tissue, a fistulous tract opening was seen outside of the surgical field. Surgical exploration proceeded medially, and an abscess pocket was found and excised en bloc (Figure 3).

The surgical site was cleaned daily, filled with povidone-soaked gauze, and then covered with foam dressing material. The wound area was scrubbed with povidone-soaked gauze at each dressing change. When there was a lot of discharge, the dressing was changed twice a day. Use of a continuous negative pressure wound therapy system was rejected by the patient due to the inconvenience of the application. 

On hospital day 7, treatment with a fasciocutaneous flap and a split-thickness skin graft measuring 100 cm² in size and with a thickness of 0.2 mm, harvested from the anterolateral thigh using an Acculan 3 Dermatome (Aesculap AG), was performed under general anesthesia. Antibiotic ointment was applied to the skin graft, and tie-over dressing with ointment gauze and cotton balls was placed. Tissue cultures of surgical specimens were conducted for routine microbiology and mycobacteriosis. Histopathological results of the surgical specimen showed chronic ulcerative inflammation with abscess, granulation tissue, and foreign body reactions, as well as a few keratins.

Complete wound healing was noted 35 days after reconstruction (Figure 4). 

Cellulitis is a skin infection that occurs when bacteria enter the skin through a wound, cut, or insect bite. In most cases, cellulitis can be diagnosed via physical examination by a health care professional based on the typical appearance of the skin and symptoms such as redness, swelling, warmth, and pain. Occasionally, blisters may rupture, expelling pus and necrotic tissue.^1,2 Cellulitis can be caused by different types of bacteria, but the most common are Streptococcus and S. aureus.^3,4 It can be divided into nonpurulent and purulent cellulitis and is managed according to the degree of infection and risk factors. Purulent cellulitis is potentially attributable to S. aureus and should be managed empirically for methicillin-resistant S. aureus infection until culture results are available. Generally, antibiotics are prescribed for 7 to 14 days, but such treatment may need to be extended for more severe cases. If symptoms do not improve within 24 to 72 hours of antibiotic administration, the possibility of treatment failure or misdiagnosis should be considered.^1,2 Incision and drainage is not indicated for cutaneous cellulitis without an underlying abscess.

Abscesses can occur in various parts of the body, including the skin, internal organs, and soft tissues. A subcutaneous abscess often results from the introduction of bacteria through a wound, hair follicle, or other skin opening. An abscess generally begins when bacteria multiply within a contained space, such as beneath the epidermis or the lumen of a hair follicle. Incision and drainage is crucial for managing the loculated collections of infectious material.⁵ 

Surgical treatment is required when the clinical response to antibiotic treatment is delayed and an abscess develops or when management of the underlying cause is important. Antibiotics cannot penetrate effectively due to poor blood circulation to the center of necrosis, and infected necrotic tissue does not decompose naturally, so it must be removed. Surgery eliminates pathogens and toxins, removes necrotic tissue and dead white blood cells, and makes it possible for macrophages, antibiotics, and opsonins to reach the causative microorganism. Localized skin abscesses without accompanying cellulitis can be managed without subsequent antibiotic treatment after a successful drainage procedure.⁶

Common reasons for treatment failure of skin and soft tissue infections include the presence of unidentified infecting foci and resistant pathogens. In the face of refractory skin and soft tissue infections, efforts should be made to find the underlying cause. Nontuberculous mycobacterial infection, underlying osteomyelitis, foreign bodies, malignancy, and other etiologies^7-10 may be unseen causes. In the patient in the current report, additional diagnostic procedures were within normal limits, and tissue culture revealed no growth of nontuberculous mycobacteriosis. Recurrent infection may also occur as a result of epidemiologic risk factors, such as host immunosuppression. The patient in the current report had diabetes, but he had no other predisposition to infection.

This case report has limitations. Only 1 patient was included. Additionally, magnetic resonance imaging studies or contrast fistulogram should have been done in the preoperative assessment, but these studies were not conducted because of the financial burden to the patient. 

In the case of recurrent or chronic inflammation, surveillance for the underlying cause is crucial. A meticulous inspection of the lesion is necessary to identify the possible existence of an underlying abscess, and a CT scan can help determine the extent of infection. In the case of the 65-year-old male patient discussed in this report, surgical intervention was mandatory to treat a hidden abscess. The hidden abscess was the root cause of the patient’s chronic cellulitis, with the abscess identified intraoperatively after rigorous prior therapies comprising repeated incision and drainage procedures. This case highlights the importance of suspicion for other causes and careful exploration when skin and soft tissue infection does not heal despite appropriate medications and surgical intervention.  

Authors: Chi Young Bang, MD, PhD¹; Seung Ho Lee, MD¹; Kunyong Sung, MD, PhD^1,2; Chanho Jeong, MD¹; Sang-Yeul Lee, MD, PhD¹; and Suk Joon Oh, MD, PhD¹

Affiliations: ¹Department of Plastic and Reconstructive Surgery, Kangwon National University Hospital, Chuncheon, Republic of Korea; ²Department of Plastic and Reconstructive Surgery, Kangwon National University School of Medicine, Chuncheon, Republic of Korea

Disclosure: The authors disclose no financial or other conflicts of interest.

Ethical Approval: This study was approved by the Institutional Review Board in Kangwon National University Hospital. The patient provided written informed consent for the publication of their case and use of the images published in this article. 

Correspondence: Kunyong Sung, MD, PhD; Department of Plastic and Reconstructive Surgery, Kangwon National University Hospital, Baekryeong-ro 156, Chuncheon 200-722, Republic of Korea; ps@kangwon.ac.kr

Manuscript Accepted: July 25, 2024