| disease | Cellulitis |
| alias | Phlegmon Cellulitis |
Cellulitis (Phlegmon Cellulitis) is a suppurative infection of the subcutaneous tissue.
bubble_chart Etiology
The main pathogenic bacteria are hemolytic streptococci, followed by Staphylococcus aureus. It can also be caused by anaerobic or saprophytic bacteria invading subcutaneous tissue from the external environment. Additionally, it may result from direct spread of other local purulent infections or be caused by lymphatic or hematogenous infections.
bubble_chart Clinical Manifestations
Initially, it presents as a poorly defined, diffuse infiltrative patch, followed by rapid progression and worsening of inflammatory symptoms, including local redness, swelling, heat, and pain, with significant pitting edema and tenderness. The central part of the rash first appears as a swollen, hardened patch, which later softens to form an abscess, discharging pus and necrotic tissue upon rupture. Patients with acute sexually transmitted diseases often experience high fever, shivering, headache, and general malaise. Some may also develop lymphadenitis, lymphangitis, gangrene, metastatic abscesses, or severe sepsis. Cellulitis can occur in any part of the body but is most common in the limbs and face. When it occurs in the fingers or toes, it is referred to as snake-head whitlow (felon). Recurrent cellulitis involves repeated episodes of the aforementioned symptoms, with erythema that may or may not be obvious or even entirely absent. Systemic symptoms are mild or nonexistent, but persistent swelling can eventually lead to chronic lymphedema.
bubble_chart Auxiliary Examination
The pathological changes of this disease involve extensive acute suppurative inflammation in the dermis and subcutaneous tissue, with infiltration of neutrophils and lymphocytes, dilation of blood vessels and lymphatic vessels, and sometimes vascular thrombosis. Hair follicles, sebaceous glands, and sweat glands are destroyed. In advanced stages, granulomas formed by fibroblasts, histiocytes, and giant cells can be observed.
bubble_chart Treatment Measures1. Systemic Therapy
(1) In the early stage, administer sufficient and highly effective antibiotics. The first choice is penicillin at 4.8–8 million units/day intravenously. For those allergic, erythromycin at 1–1.5 g/day intravenously can be used. Alternatively, ciprofloxacin at 0.2 g/dose, twice daily intravenously, or oral ofloxacin at 0.2 g/dose, twice daily may be selected. Cefazolin at 6 g/day intravenously or broad-spectrum cephalosporin antibiotics can also be used. The general course of treatment is 10–14 days, and it should be maintained for a period after the skin lesions subside.
(2) Supplement vitamins, such as vitamin C and compound vitamin B.
(3) Symptomatic treatment includes providing analgesics and antipyretics, such as APC and pain relief tablets.
2. Local Therapy
(1) For cases with suppuration, incision and drainage should be performed.
(2) Apply local wet compresses with 50% magnesium sulfate or saline, followed by external application of 10% ichthammol ointment and bandaging.
(3) Local ultraviolet irradiation or physical therapies such as shortwave therapy.
Based on characteristics such as indistinct borders of redness and swelling, pitting edema and tenderness, central rash swelling followed by softening, fluctuation, and ulceration, a diagnosis can be made. However, it is important to differentiate from the following conditions:
1. Erysipelas: Erysipelas is a superficial inflammation with mild infiltration and does not form deep abscesses. The skin lesions present as clearly demarcated inflammatory erythema, and the edema is less pronounced compared to this condition.
3. Angioedema: Angioedema presents only with edema, without erythema, suppuration, or systemic symptoms, and resolves quickly.
