Medical Management of Cellulitis


Vijayalakshmi B1, Dhanraj Ganapathy2

1Intern, Department of Prosthodontics, Saveetha Dental College, Chennai-77, India

2Professor and Head of the Department, Saveetha Dental College, Chennai -77, India.

Corresponding Author E-mail :



Cellulitis: An acute spreading bacterial infection affecting the dermis and subcutaneous layer characterized by local findings of tenderness, erythema, increased warmth, swelling, and regional lymphadenopathy. Cellulitis can occur in any part of the body especially in legs and face.  The bacteria most commonly involved are streptococci and Staphylococcus aureus. When left untreated it affects the lymphatic vessels and reaches the circulation causing serious conditions. The borders of the area of redness are generally not sharp and the skin may be swollen. Lymphatic vessels may occasionally be involved. This review deals about the infection spread, symptoms, investigations and treatment in cellulitis.


KEYWORDS: Infection, management, cellulitis.




Cellulitis being a bacterial infection most commonly involves streptococci and staphylococcus aureus affecting the deeper layers of skin. The face and legs which are affected may be swollen and appears red with break in the surface of skin. The local findings are characterized by tenderness, erythema, increased warmth, swelling, and regional adenopathy. (1) Local factors causing cellulitis includes tinea pedis, ulcers, trauma, and insect bites whereas systemic factors include venous insufficiency (2), lymph oedema (3), peripheral vascular disease, diabetes mellitus and obesity. (1)


Spread of Infection:

Cellulitis can affect anyone irrespective of age and gender. Orbital cellulitis may even cause blindness, cavernous sinus clots, and inflammation of all tissues of eye. A primary lesion was defined as any wound or skin condition contiguous with the area of cellulitis, causing a break in the skin and thus representing a potential site of origin for the infection.


Cellulitis most commonly affects the lower extremities, and often presents as an acute, tender, erythematous, and swollen area of skin. In severe cases blisters, ulcers, oedema, associated lymphangitis, and lymphadenopathy may be present. Constitutional features include fever and malaise. In the late stages widespread features of sepsis including hypotension and tachycardia may also be present.


Clinical Classes of Cellulitis:

This classification was devised by Eron for skin and soft tissue infections.


Class I: patients have no signs of systemic toxicity, have no uncontrolled co-morbidities and can usually be managed with oral antimicrobials on an outpatient basis.


Class II: patients are either systemically ill or systemically well but with a co-morbidity such as peripheral vascular disease, chronic venous insufficiency or morbid obesity which may complicate or delay resolution of their infection.


Class III: patients may have a significant systemic upset such as acute confusion, tachycardia, tachypnoea, hypotension or may have unstable co-morbidities that may interfere with a response to therapy or have a limb threatening infection due to vascular compromise.


Class IV: patients have sepsis syndrome or severe life threatening infection such as necrotizing fasciitis. (4)



If cellulitis forms, there are several common symptoms. They include:

·         Swelling and redness

·         Skin sensitivity - it's sore and tender to the touch

·         Pain or warmth

·         Blisters

·         Red spots

·         Fever

·         Dimpling of the affected area

·         Appearance or leaking of pus(5)




Blood Investigation:

In blood culture, an elevated level of C reactive protein is a better indicator of bacterial infection than an elevated white cell count but a normal level of C reactive protein cannot rule out an infection. Blood cultures are rarely positive (2-4%) and contaminants may outnumber pathogens. (6) (7) Blood cultures should not be undertaken routinely but be reserved for patients where the infection has been graded as Class III or Class IV where they are more likely to yield the causative organism. Blood investigations do not appear to be clinically useful for diagnosis. (8)


National guidelines, including the Northern Ireland Clinical Resource Efficiency Support Team (CREST) 2005 guidelines on the management of cellulitis in adults, recommend taking blood cultures only inpatients that have significant systemic upset including pyrexia(>38°C).(9)


CREST guidelines suggest the use of skin biopsies and aspirations in only patients, where the diagnosis of cellulitis is in doubt.(9)



Imaging techniques are useful when there is a suspicion of an underlying abscess associated with cellulitis, necrotising fasciitis, or when the diagnosis of cellulitis is uncertain.


Doppler Ultrasound:

It is usually the first investigation to evaluate a clinical suspicion of cellulitis. Normally the subcutaneous tissue is hypoechoic with few hyperechoic strands (representing connective tissue).

·         In early cellulitis, there is a diffuse increase in the thickening and echogenicity of the subcutaneous tissue; helpful technique is to compare the tissue with contralateral side

·         Later, there is accumulation of fluid in the subcutaneous tissue, giving it a "cobble-stone appearance" (this appearance is not specific for cellulitis, but is seen in subcutaneous edema due to any cause). (10)



·         CT is used to accurately differentiate between superficial cellulitis and deep cellulitis (cellulitis associated with deep-seated infection). 

·         In uncomplicated cellulitis, CT demonstrates skin thickening, septation of the subcutaneous fat, and thickening of the underlying superficial fascia. If the infection spreads to deeper tissues, deep cellulitis, soft-tissue abscess, infectious myositis, necrotizing fasciitis, and osteomyelitis can all be detected with CT. (10)



MRI (magnetic resonance imaging) may be useful in those with an equivocal diagnosis of cellulitis or with suspicion of necrotising fasciitis. According to CREST guidelines, in the haemodynamically stable patient an MRI scan is warranted. (9)


Differential Diagnosis:

·         Deep vein thrombosis.

·         Insect bite.

·         Superficial thrombophlebitis.

·         Varicose eczema.

·         Pyoderma granulosum.

·         Chronic venous insufficiency.

·         Contact dermatitis.

·         Vasculitis.

·         Gout.

·         Septic arthritis/osteomyelitis.

·         Erythema nodosum.

·         Drug reaction.

·         Severe ischaemia/compartment syndrome.

·         Necrotising fasciitis.

·         Metastatic carcinoma (carcinoma erysipeloides). (11)


Management of the locally affected area should include the following:

·         Adequate analgesia to ensure pain relief

·         Monitoring and management of any pyrexia

·         Consider hydration – intravenous/oral

·         Recording of the site and/or limb affected

·         Mark off the extent of erythema present on admission (9)


Treatment of Cellulitis:            

General measures include rest, elevation of any affected limbs and analgesia.(12) The area of cellulitis should be clearly marked and reviewed daily for progression or regression to assess the efficacy of the antibiotic regimen.(9)Oral antimicrobials are as effective as parenteral antimicrobials for the treatment of uncomplicated cellulitis. (4) (6) Topical antibiotics should not be used in the management of cellulitis in conditions of broken or exudating skin.


Suitable Drug Therapy for Typical Cellulitis:


First line and Second line drugs as per CREST guidelines


First Line

Second Line

Class I

Flucloxacillin 500mg qds po

Penicillin allergy:

Clarithromycin 500mg bd po

Class II

Flucloxacillin 2g qds IV

Penicillin allergy:

Clarithromycin 500mg bd IV or Clindamycin 600mg tds IV

Class III

Flucloxacillin 2g qds IV

Penicillin allergy:

Clarithromycin 500mg bd IV or

Clindamycin 900mg tds IV


Class IV: Benzylpenicillin 2.4g 2-4 hourly IV + Ciprofloxacin 400mg bd IV + Clindamycin 900mg tds IV


(If allergic to penicillin use Ciprofloxacin and Clindamycin only)



·         Clindamycin is often given as a second-line treatment, if needed. (13)

·         Flucloxacillin is sometimes given with penicillin V. However, there are no published randomised controlled trials comparing flucloxacillin monotherapy with a combination of flucloxacillin and penicillin V in the management of cellulitis. (14)

·         CREST guidelines still recommend amoxicillin or flucloxacillinfor the majority of cases of cellulitis caused by S aureus, Streptococcus, or when the organism has not been identified. In those with severe cellulitis requiring admission to hospital, linezolid and vancomycin were found to have good efficacy.(15)


Drug Therapy for atypical cellulitis:

Risk Factor

First Line

Penicillin allergy

Human bite

Co-amoxiclav 625mg tds po

Clarithromycin 500mg bd poor Doxycycline 100mg bd po and Metronidazole 400mg tds po

Cat/Dog bite

Co-amoxiclav 625mg tds po

Doxycycline 100mg bd poand Metronidazole 400mg tds po

Exposure to fresh water at site of skin and break

Ciprofloxacin 750mg bd po and Flucloxacillin 500mg qds po

Ciprofloxacin 750mg bd poand Clarithromycin 500mg bd po



Lymphoedema is the most important risk factor in the development of recurrent cellulitis. (16) As lymphoedema and venous insufficiency are often associated, it would clearly be best tocombine these two as the main risk factors for recurrent cellulitis. Each episode of cellulitis adds to the lymphatic damage. Therefore, prophylaxis should be considered for patients with recurrent episodes.


Small series have reported benefit from prophylaxis with low dose Penicillin V or Erythromycin (both typically 250mg bd) or with intermittent IM depot Penicillin.(1) (17) (18) (19) (20) However it is not proven whether a prolonged course of antibiotics after a single acute episode will prevent future recurrences.



Concerning the diagnosis of cellulitis, there is considerable discordance between specialist attending diagnosis or general physician diagnosis. Often, non-cellulitis cases are non-infectious and do not require hospitalization or the use of parenteral antibiotics. Usually around 95% of people recover after seven to ten days of treatment.(21) But misdiagnosis of cellulitis may lead to unnecessary hospitalization and antibiotic use. It is better to check for antibiotic sensitivity before prescribing or it may lead to serious conditions in case of penicillin allergy.



1)       Cox NH et al., Management and morbidity of cellulitis of the leg. J R Soc Med 1998; 91:634-7.

2)       Jorup-Rönström C et al., Recurrent erysipelas: predisposing factors and cost of prophylaxis. Infection 1987; 15:105-6.

3)       Keeley VL. Lymphoedema and cellulitis: chicken or egg? Br J Dermatol 2008;158:1175-6.

4)       Aboltins CA, et al; Oral versus parenteral antimicrobials for the treatment of cellulitis: a randomized non-inferiority trial. J Antimicrob Chemother. 2015 Feb;70 (2):581-6. doi: 10.1093/jac/dku397. Epub 2014 Oct 21.

5)       Paul M. Newell et al.,”Value of Needle Aspiration in Bacteriologic Diagnosis of Cellulitis in Adults “, Journal of Clinical Microbiology, Vol 26. No.3; p 401-404.

6)       Miller LG et al; Clindamycin versus trimethoprim-sulfamethoxazole for uncomplicated skin infections. N Engl J Med. 2015 Mar 19; 372 (12) : 1093-103. doi: 10.1056/NEJMoa1403789.

7)       Consensus Document on the Management of Cellulitis in Lymphoedema; British Lymphology Society (2013)

8)       Chan YL et al., C-reactive protein as an indicator of bacterial infection of adult patients in the emergency department. Chang GungMed J 2002; 25:437-45.

9)       Clinical Resource Efficiency Support Team (2005) Guidelines on the management of cellulitis in adults. Crest, Belfast. % 20guidelines, % 20 CREST , % 2005 .pdf.

10)    Dr Henry knipe et al.”Cellulitis”,

11)    Stevens et al.,. (2014-06-18). "Practice

12)    Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America". Clinical Infectious Diseases 59:ciu296. doi:10.1093/cid/ciu296. ISSN 1058-4838. PMID 24947530.

13)    Phoenix G et al ; Diagnosis and management of cellulitis. BMJ. 2012 Aug 7; 345:e4955. doi: 10.1136/bmj.e4955.

14)    Eron, L. J. 2003. The admission, discharge and oral switch decision processes in patients with skin and soft tissue infections. Current Treatment Options in Infectious Diseases, 5 : 245-250.

15)    Quirke M et al; Are two penicillins better than one? A systematic review of oral flucloxacillin and penicillin V versus oral flucloxacillin alone for the emergency department treatment of cellulitis. Eur J Emerg Med. 2014 Jun; 21(3):170-4. doi: 10.1097/MEJ.0b013e328360d980.

16)    Stevens DL  et al. Practice guidelines for the diagnosis and management of skin and soft-tissue infections. Clin InfectDis 2005; 41:1373-1406.

17)    Dupuy, A et al. 1999. Risk factors for erysipelas of the leg: case control study. Br. Med. J , 318 1591-4.

18)    Duvanel, T. et al., 1986. Evaluation of prophylactic Benzanthine-Pencillin in the prevention of recurrent erysipelas. Dermatologica 173, 205-208

19)    Kremer, M. Et al 1991. Long term antimicrobial therapy in the prevention of recurrent soft-tissue infections. J. Infection 22, 37-40.

20)    Bourna, al . 1988. Recurrent acute leg cellulitis in patients after radical vulvectomy. Gynaecol Oncol, 29, 50-57.

21)    Sjoblom, A. et al. 1993. Antibiotic prophylaxis in recurrent erysipelas. Infection, 21, 390-392.

22)    Mistry, RD (Oct 2013). "Skin and soft tissue infections.". Pediatric clinics of North America 60 (5): 1063–82. doi:10.1016/j.pcl.2013.06.011. PMID 24093896.




Received on 19.07.2016             Modified on 28.07.2016

Accepted on 06.08.2016           © RJPT All right reserved

Research J. Pharm. and Tech 2016; 9(11):2067-2070.

DOI: 10.5958/0974-360X.2016.00422.4