A subcutaneous abscess is a pus-filled cavity located in the superficial skin layers caused by penetration of the skin by bacteria following a cut or other dermal disruption [1]. The implicated pathogens are normal skin flora bacteria [2] [3] such as Staphylococcus aureus (most common), group A Streptococcus, and anaerobes [2] [3] [4]. A subcutaneous abscess is circumscribed by tissue containing inflammatory cells and the purulent collection is composed of bacteria, immune cells, and material from the surrounding necrotic subcutaneous tissue [1]. Abscesses and other skin and soft tissue infections (SSTIs) are a common cause of visits to the emergency department and the doctor's office [5].

A subcutaneous abscess presents as a painful edematous mass with induration [4]. They typically form on regions in the body predisposed to friction, also known as intertriginous areas, although they can appear anywhere [6]. This may manifest as a furuncle, which emerges from a hair follicle, or carbuncles which are clusters of infected follicles [6]. Subcutaneous abscesses can rupture spontaneously in which the overlying skin on the abscess thins out and possibly becomes yellow or white, reflecting the pus collection.

Risk factors for abscesses and SSTIs, in general, include advanced age, trauma, diabetes mellitus, malignancy, immunocompromised state, obesity, and so forth [7] [8] [9]. Additionally, individuals such as athletes playing in close-contact sport and military individuals living in close proximity are predisposed to outbreaks [10] [11].

Physical exam

A superficial abscess is characterized by tenderness, warmth, erythema, and fluctuance. Note that generalized symptoms such as fever and chills do not occur with these simple abscesses [12].

• Fever

  Signs and symptoms include the presence of a swollen, tender, and erythematous nodular lesion in the skin associated with fever and chills. [fpnotebook.com]

  […] include: a smooth swelling under your skin that can feel hard or firm pain and tenderness in the affected area warmth and redness in the affected area a visible build-up of white or yellow pus under the skin in the affected area a high temperature (fever [nhs.uk]

  Note that generalized symptoms such as fever and chills do not occur with these simple abscesses. [symptoma.com]

  Symptoms Symptoms may include: Fever or chills, in some cases Local swelling around the infected spot Hardened skin tissue Skin lesion that may be an open or closed sore, or a raised area Redness, tenderness, and warmth in the area Fluid or pus drainage [account.allinahealth.org]

  A previously healthy 18-year-old man was admitted to the hospital with a 3-month history of coughing, expectoration of reddish sputum, weight loss, and fever; a small region of swelling had developed on his anterior chest wall in the preceding week. [nejm.org]

• Chills

  Signs and symptoms include the presence of a swollen, tender, and erythematous nodular lesion in the skin associated with fever and chills. [fpnotebook.com]

  […] include: a smooth swelling under your skin that can feel hard or firm pain and tenderness in the affected area warmth and redness in the affected area a visible build-up of white or yellow pus under the skin in the affected area a high temperature (fever) chills [nhs.uk]

  Note that generalized symptoms such as fever and chills do not occur with these simple abscesses. [symptoma.com]

  Symptoms Symptoms may include: Fever or chills, in some cases Local swelling around the infected spot Hardened skin tissue Skin lesion that may be an open or closed sore, or a raised area Redness, tenderness, and warmth in the area Fluid or pus drainage [account.allinahealth.org]

• Rigor

  If there is bacteremia patient may present with systemic signs of sepsis such as fever, rigors, and raised inflammatory markers. [radiopaedia.org]

  Fever, malaise, and rigors are common as the area of cellulitis evolves. Streptococcal cellulitis generally progresses more rapidly than staphylococcal infections. [infectiousdiseaseadvisor.com]

• Malaise

  She was otherwise well with no history of general malaise or weight loss. Initially, the lesions appeared on her left abdominal wall and 3 months later, they had increased in size and were present bilaterally (Fig. 1). [medicaljournals.se]

  Fever, malaise, and rigors are common as the area of cellulitis evolves. Streptococcal cellulitis generally progresses more rapidly than staphylococcal infections. [infectiousdiseaseadvisor.com]

• Localized Edema

  The process begins as local cellulitis, with erythema, edema, pain, and marked tenderness. Like more superficial cellulitidies, the margins of infection are poorly defined. [infectiousdiseaseadvisor.com]

• Thrombosis

  The inflammation of the deep fascia causes thrombosis of the dermal vessels, and it is this thrombosis that is responsible for the secondary necrosis of the overlying subcutaneous tissue and skin. [emedicine.medscape.com]

  Clinical differential diagnoses include: erysipelas deep vein thrombosis myriad of non-infective erythematous rashes infectious myositis necrotizing fasciitis osteomyelitis septic arthritis subcutaneous abscess Promoted articles (advertising) [radiopaedia.org]

  An ultrasound examination showed thrombosis in the bilateral femoral veins and popliteal veins. In addition, a 51 × 16 mm hypoechoic lesion was detected in the left subcutaneous perineal region. [bmcinfectdis.biomedcentral.com]

• Skin Lesion

  Cutaneous cryptococcosis can be caused by direct contact or via blood dissemination from the primary site of infection site. [1] The skin lesions may appear as nodules, ulcers, cellulitis, or molluscum contagiosum-like lesions. [2] We report a patient [ijdvl.com]

  Symptoms Symptoms may include: Fever or chills, in some cases Local swelling around the infected spot Hardened skin tissue Skin lesion that may be an open or closed sore, or a raised area Redness, tenderness, and warmth in the area Fluid or pus drainage [account.allinahealth.org]

  Symptoms may include: Fever or chills, in some cases Local swelling around the infected spot Hardened skin tissue Skin lesion that may be an open or closed sore, or a raised area Redness, tenderness, and warmth in the area Fluid or pus drainage Your health [medlineplus.gov]

  lesion that was draining purulent fluid, on his left medial lower extremity (figure 1). [casereports.bmj.com]

• Increased Sweating

  General symptoms of an internal abscess can include: discomfort in the area of the abscess fever increased sweating feeling sick vomiting chills pain or swelling in your tummy (abdomen) loss of appetite and weight loss extreme tiredness (fatigue) diarrhoea [nhs.uk]

• Irritability

  In some cases sterile abscess formation has been described where a irritant drug or substance is injected into the skin, resulting in aseptic inflammation and abscess formation. [radiopaedia.org]

  This sounds to me like an extreme irritant reaction. Test prop is a known irritant, which is why it is not usually injected subq. [allthingsmale.com]

  Predisposing factors Factors predisposing to the development of SSTIs include the following: Breach in the epidermis Dry and irritated skin Immunocompromised status - Malnutrition, hypoproteinemia, burns, diabetes mellitus, AIDS Chronic venous insufficiency [emedicine.medscape.com]

  Irritable bowel syndrome (IBS) is a common disorder affecting over 15 percent of the population. [fascrs.org]

  Chemical irritants such as smoke from methamphetamine, immunosuppression arising from chemotherapy, or chronic immunosuppressive medical conditions such as HIV/AIDs can predispose individuals to dental caries.[3][4] Epidemiology Dental caries and poor [ncbi.nlm.nih.gov]

The diagnosis of a subcutaneous abscess is clinical, which is based on patient history and focuses on risk factors and visual inspection of the abscess. Laboratory tests, such as complete blood count (CBC) and blood cultures, are reserved for severe and deep infections [4]. Moreover, blood cultures do not influence the management of simple abscesses, especially in healthy individuals [13] [14]. Imaging is not required for subcutaneous abscesses or other simple SSTIs [4].

Note that the workup for complicated SSTIs is extensive and includes needle aspiration of fluid and possibly tissue biopsy [15]. Blood cultures are indicated in patients with systemic involvement, deep tissue infections, and immunocompromised individuals[16] [17]. Furthermore, complicated cases may warrant imaging such as computed tomography (CT) scanning, which is the recommended study [18]. Ultrasonography, magnetic resonance imaging (MRI), and other modalities may be used for further evaluation if needed.

S. aureus causes significant morbidity and mortality in patients who receive acupuncture treatment. [ncbi.nlm.nih.gov]

The safety and efficacy of itraconazole for the treatment of patients with eumycetoma due to Madurella mycetomatis. [journals.plos.org]

Early diagnosis of aspergillosis is a key to successful treatment. [bmcinfectdis.biomedcentral.com]

Disclaimer : The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. [practo.com]

Prognosis Prognosis for a dental abscess is very good. Prognosis can be quite poor if a dental abscess is left untreated; mortality rate can increase to 40% if patients develop mediastinitis from descending infection (Shweta et al. 2013). [ncbi.nlm.nih.gov]

Treatment and prognosis Uncomplicated cellulitis is usually treated conservatively with antibiotics and locally supportive measures. [radiopaedia.org]

Outlook (Prognosis) Most skin abscesses can be cured with proper treatment. Infections caused by MRSA respond to specific antibiotics. [account.allinahealth.org]

[…] tuberculosis is generally associated with an underlying disorder, immunosuppressive therapy, or local injury, but a recent review on tuberculous myositis in Taiwan showed that 71.4% of patients with tubercular myositis had no underlying disease. 2 The prognosis [academic.oup.com]

The prognosis is generally excellent, but some individuals may suffer from recurrent abscesses requiring medical attention. Most people do not require antibiotics. The pain should improve almost immediately after drainage and subside more each day. [emedicinehealth.com]

Approximately 1% to 2.5% of patients present with this chief complaint.1–3 Abscesses occur in numerous anatomical areas with varied etiology and bacteriology. An abscess is a tender and fluctuant mass located in the dermal or subdermal tissue. [accessemergencymedicine.mhmedical.com]

Etiology: A wide variety of bacteria and yeasts are associated with folliculitis. [infectiousdiseaseadvisor.com]

Periapical abscess – etiology, pathogenesis and epidemiology. Przegl Epidemiol. 2017;71(3):417-428. [PubMed: 29186939] [ncbi.nlm.nih.gov]

Etiology Numerous organisms can cause abscesses, but the most common is Organisms may enter the tissue by Direct implantation (eg, penetrating trauma with a contaminated object) Spread from an established, contiguous infection Dissemination via lymphatic [msdmanuals.com]

Identification and first report of Inonotus (Phellinus) tropicalis as an etiologic agent in a patient with chronic granulomatous disease. J Clin Microbiol. 2005;43:982–7. CrossRef PubMedCentral PubMed Google Scholar 18. [link.springer.com]

We studied the epidemiological and clinical characteristics of Nocardia infections reported in Japan from 2000 to 2008 and identified 92 cases using the medical article search engine Ichushi-Web (Japan Medical Abstract Society). [ncbi.nlm.nih.gov]

Galván B, Mariscal F (2006) Epidemiology of candidemia in ICU. Rev Iberoam Micol 23: 12-15. [mycology.imedpub.com]

Epidemiology: Cellulitis may occur in individuals of any age. [infectiousdiseaseadvisor.com]

Molecular epidemiology of Corynebacterium diphtheriae from northwestern Russia and surrounding countries studied by using ribotyping and pulsed-field gel electrophoresis.. J Clin Microbiol 33 :, 1080– – 1083. [PubMed] [Google Scholar] Dias A. [jmm.microbiologyresearch.org]

The pathophysiology of this disease is not clear, it is believed to occur by immunological cross-reactivity between the infecting organism and the synovial membrane component, causing inflammation of the synovial membrane without infection to the joint [clinmedjournals.org]

Provider practices may shift because of the population, racial distribution, and socioeconomic demographics of the community.[5][6] Pathophysiology Tooth Anatomy and Structure The anatomy of the tooth consists of the crown of the tooth which is connected [ncbi.nlm.nih.gov]

Appreciating the Importance of the Pathophysiology of Perianal Crohn's Disease in Guiding Biological and Surgical Therapy. Dis Colon Rectum 2018;61:529-531. 51. Yassin NA, Askari A, Warusavitarne J, et al. [dsgh.dk]

Scrotal subcutaneous abscess should be prevented from progressing to Fournier's gangrene with early and appropriate treatment. [ncbi.nlm.nih.gov]

[…] reoccurrence. o For example, for repeated incision and drainage of an abscessed paronychia, the medical record should document any additional measures taken to prevent reoccurrence and/or the reason for not performing more definitive treatment (e.g., [automatedworldhealth.com]

Preventing abscesses depends on where they develop. For example, good hygiene can help prevent skin abscesses. Dental hygiene and routine care will prevent tooth abscesses. Ambrose G, Berlin D. Incision and drainage. [medlineplus.gov]

For larger or persistent skin abscesses, your GP may prescribe a course of antibiotics to help clear the infection and prevent it from spreading. [nhs.uk]

[…] and dry to prevent infection. [account.allinahealth.org]

1. Townsend CM, Beauchamp RD, Mattox KL, Evers BM. Surgical Infections and Choice of Antibiotics. In: Sabiston Textbook of Surgery: the biological basis of modern surgical practice. 18th ed. Philadelphia,PA: Saunders Elsevier; 2007: 299-327.
2. Brook I. Microbiology of polymicrobial abscesses and implications for therapy. J Antimicrob Chemother. 2002; 50(6):805-810.
3. Dryden MS. Complicated skin and soft tissue infection. J Antimicrob Chemother. 2010;65(Suppl 3):iii35-44.
4. Ramakrishnan K, Salinas RC, Agudelo Higuita NI. Skin and Soft Tissue Infections. Am Fam Physician. 2015;92(6):474-483.
5. Hersh AL, Chambers HF, Maselli JH, Gonzales R. National trends in ambulatory visits and antibiotic prescribing for skin and soft-tissue infections. Arch Intern Med. 2008;168(14):1585–1591.
6. Stulberg DL, Penrod MA, Blatny RA. Common Bacterial Skin Infections. Am Fam Physician. 2002;66(1):119-125.
7. Ki V, Rotstein C. Bacterial skin and soft tissue infections in adults: a review of their epidemiology, pathogenesis, diagnosis, treatment and site of care. Can J Infect Dis Med Microbiol. 2008;19(2):173–184.
8. Gabillot-Carré M, Roujeau JC. Acute bacterial skin infections and cellulitis. Curr Opin Infect Dis. 2007;20(2):118–123.
9. Salgado CD, Farr BM, Calfee DP. Community-acquiredmethicillin-resistant Staphylococcus aureus: a meta-analysis of prevalence and risk factors. Clin Infect Dis. 2003;36(2):131–139.
10. May L, Porter C, Tribble D. Self-reported incidence of skin and soft tissue infections among deployed US military. Travel Med Infect Dis. 2011;9(4):213–220.
11. Decker CF. Skin and soft tissue infections in the athlete. Dis Mon. 2010;56(7):414–421.
12. Long SS, Pickering LK, Prober CG. Subcutaneous Tissue Infections and Abscesses. In: Principles and Practice of Pediatric Infectious Diseases Revised Reprint. 3rd ed. New York: Elsevier; 2008:457-464.
13. Payne CJ, Walker TW, Karcher AM, et al. Are routine microbiological investigations indicated in the management of non-perianal cutaneous abscesses? Surgeon. 2008;6(4):204–206.
14. Mills AM, Chen EH. Are blood cultures necessary in adults with cellulitis? Ann Emerg Med. 2005;45(5):548–549.
15. Breen JO. Skin and soft tissue infections in immunocompetent patients. Am Fam Physician. 2010;81(7):893-899.
16. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections. Clin Infect Dis. 2014;59(2):e10–e52.
17. Baron EJ, Miller JM, Weinstein MP, et al. A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases. Clin Infect Dis. 2013;57(4):e22–e121.
18. Tayal VS, Hasan N, Norton HJ, et al. The effect of soft-tissue ultrasound on the management of cellulitis in the emergency department. Acad Emerg Med. 2006;13(4): 384-388.