Inflammations and Infections of the Skin and Adjacent Tissues Other than Bone
A Practical Approach to Management
Reynaldo O. Joson, MD, MHA, MHPEd, MSc Surg
June 2, 2012
These thoughts, perceptions, opinions, and recommendations (TPORs) of mine do not deal with inflammation and infection of the bones, which in medical parlance, is called osteomyelitis. The TPOR is confined to structures more superficial to the bone, that is, the skin, subcutaneous tissues (the fatty layer), and the muscle, for which I will use the term “skin and adjacent tissues” to facilitate my write-up.
Inflammations and infections on or of the skin and adjacent tissues are very common in the life of human beings on earth.
There is a medical jungle in the Internet that contains so many overlapping terms and descriptions and complicated treatment recommendations.
In this TPOR of mine, I will try to recommend a practical approach to management, simplifying the diagnostic labelling and treatment approaches.
Inflammation vs Infection
Inflammation is not synonymous with infection.
Inflammation is a response of the skin and adjacent tissues to harmful stimuli, such as micro-organisms, trauma, and irritants. It is usually manifested by redness and tenderness on the affected area in the skin and adjacent tissues. The traditional names of the signs and symptoms of inflammation, which are Latin in origin, consist of the following:
- Rubor (redness)
- Tumor (swelling)
- Dolor (tenderness and pain)
- Calor (heat)
- Functio laesa (loss of function because of pain)
Infection is a disease caused by a specific inciting organism (bacteria, fungal, viral, parasite, prion, etc.). In an infection of the skin and adjacent tissues, there may or may not be signs and symptoms of inflammation. In an acute infection, however, there are usually signs and symptoms of inflammation. In a chronic one, there are usually none.
Diagnostic Labelling of Inflammations and Infections of Skin and Adjacent Tissues
Inflammation is used when any one of the cardinal signs and symptoms of acute inflammation (redness, swelling, tenderness, heat, and loss of functions) is present. Per se, it does not specify whether an infection is present or not. If an infection is present together with signs and symptoms of inflammation, the diagnostic label should be on the infection.
Cellulitis is an acute inflammatory condition of the skin and adjacent tissues. As such, it can be synonymous with “inflammation.” However, in the medical community, cellulitis is often used to imply there is an infection going on. Thus, if there is evident redness on the skin and infection is suspected and there is still no evident abscess formation (collection of pus), cellulitis is used (see picture below).
Abscess is an infection of the skin and adjacent tissues in which there is an associated collection of pus (see pictures below). There are usually associated signs and symptoms of inflammation, particularly, redness, tenderness and pain.
Abscesses may vary in size. There is no universally accepted way of classifying the size, just small, large, and not so large. To illustrate the complexity In the medical community, “folliculitis” is used to refer to a very small abscess of the hair follicle (about 1-2 mm). The moment the abscess of the hair follicle is larger than the 1-2 mm, then it is called a “furuncle” or “boil” in common parlance. The moment there is a merging of several furuncles into a deep abscess with multiple sites draining pus, the disease is known as carbuncle. Thus, from the example, one sees the effect of the size in the terminologies. To simplify things, particularly for the lay people, it will be enough to know what is an abscess and whether it is present or not.
Abscesses may vary in location. The abscess may be superficial to the muscle or in the muscle layer. If the abscess is in the muscle layer, then “intramuscular abscess” is used as a diagnostic label. If the abscess is superficial to the muscle layer and confined to the subcutaneous layer, then “subcutaneous abscess” is used. If the abscess is confined to the skin layer, then “skin abscess” is used.
Necrotizing infection of the skin and adjacent tissues is a rare but a very severe type of infection. It is usually caused by bacterial microorganisms. As the word “necrotizing” implies, it destroys the skin, subcutaneous tissues, and muscles rapidly. Necrotizing infection is a severe and serious type of infection as there is a high risk for disability and death. Necrotizing infection is suspected when the initial redness and swelling on the skin rapidly progresses to purplish-bluish and even blackish discoloration. There may be blistering of the skin. Together with the above signs, the patient with necrotizing infection looks very very sick.
Inflammation not due or associated with infection – warm compress and/or analgesics if with intolerable pain; close monitoring, with focus on progression to a more severe condition.
Inflammation associated with infection – treatment of the infection (see below).
Cellulitis associated with infection – primary treatment approach – treatment of the infection with antibiotics.
Abscess – primary treatment approach – treatment of the abscess by drainage of the pus, with or without antibiotics.
Necrotizing infection – primary treatment approach – treatment of the necrotizing infection by debridement (surgical excision of dead tissues), with intravenous antibiotics.