Wound Classification

A wound can be defined as the loss of cutaneous teguments represented not only on the disruption of the skin, it can also exist affectation and loss of subcutaneous tissues, these can include muscular tissue and even bones.

The easiest way to classify a wound is by its complexity, that way we can classify a larger number of wounds and simplify the explanation of its treatment:

Simple Wounds

Simple wounds are acute injuries, such as, surgical wounds, scrapings, light abrasions, and chronic wounds, that would not close by themselves and might require specialized attention, but all of these wounds with the proper care and treatments, close completely without recurrence.

Complex Wounds

Complex wounds must have at least one of the following:

  1. Severe loss of teguments in extension and deepness: This is an important criterion regardless of the acuteness or chronicity of the wound.
  2. It frequently comes with infection and it can increment the tissue loss.
  3. The viability of the superficial tissues is compromise, with necrosis or signs of ischemia, localized or in a large extension, specially around the edges of the wound, this increments the loss of tissue.
  4. Presents complications inherent to systemic pathologies that block the normal regeneration of tissue or can cause the failure of the wound healing process, such as: vasculitis or diabetic foot ulcers.
  5. Presents a torpid evolution towards the perpetuity of the wound’s chronicity.

Complex wounds require special care that should be given by an interdisciplinary team, dedicated to those issues.

Most common complex wounds:

  • Diabet foot ulcers.
  • Chronic Venous Ulcers.
  • Pressure Ulcers.
  • Dehiscence wounds of the abdominal wall.
  • Ulcers due to extended necrotic processes cause by infection.
  • Chronic ulcers related to vasculitis and causes by immunosuppressant’s.
  • Burns.

Ulcer’s Classification according to Deepness.

Stage Characteristics
0 Intact Epidermis and Adhering. There can be edema or erythema that will diminish when pressure is applied. It has more than 15mm of diameter.

Ulcers that affects the epidermis and dermis.

Ulcerous wound on the dermic tissue, with a dark color under the skin of more than 5mm of diameter.

2 Ulcer that affects subcutaneous tissue.
3 Ulcer that affects muscle.
4 Ulcers that affect tendons, bones or leaves the insides exposed.

Classification of Ulcers according to the Tissue Structure

Grade Characteristics
I The base of the wound is covered by granulated tissue, there is no necrosis or fibrin.
II The base of the wound is 50% covered by granulated tissue and there is presence of necrotic tissue.
III The base of the ulcer is less than 50% covered by granulated tissue and more than 50% is constituted by fibrin, there is no necrosis.
IV The necrotic tissue is present on more than 50% of the wound, less than 50% is fibrin, there is no granulated tissue.


Without the intention to cover more on this section that the causes of this condition, only the most common and coincidental factors are explained on this table:

Factor Characteristics
Physiological Edema on legs

The patients that show edema on the evening, improve during the night and is tolerated due to the elasticity of its tissue. But the complex leg patients, have an inverted cycle, in which there is no diminution of the edema with rest, due to the loss of tone on the blood vessels and valves insufficiency.

Less resistance on the leg’s skin

The skin on the legs, especially on the low third, is of a remarkable fragility and its power of regeneration is low.

The small circulatory deviations happen earlier and manifest themselves due to gravitatory factors derived of the erect position of the patient.

Heritage Factor There are people in favor and against this idea, especially talking about valvular venous insufficiency.
Vascular Factor

The venous system of the lower extremities is formed by two components: The deep veins, and the superficial formed by a system of communicative blood vessels that regulate the flow between both components.

There is a valve on the veins that regulates the blood flow against the gravitational effect, pushed by the heart; when this fails it produces a stagnation of the blood columns.

This is the venous stage in which the alterations of the venous walls occur, the dilatation of them, cause the formation of varicosities.

On the other hand, the veins can go trough inflammatory stages on their walls, causing phlebitis, which contributes on the formation of clogs. This is a long process of chronic venous insufficiency.

Orthostatic Position

The human posture, favors the increase of pressure on the veins, to this mechanism we have to include many factors that increase the blood pressure, such as pregnancy or pelvic tumors.

Standing up is a predisposing element, walking is not.

Neurologic Factor

Especially present on diabetic foot ulcers, that have lost completely or partially the sensitivity.

When the skin is attacked repeatedly and due to the lack of pain, pressure, ischemia or repeated traumatism, there is a high risk of producing an ulcer.

These types of wounds are painless, persistent, relatively non inflammatory and can appear on pressure points.

Traumatism It can trigger the ulcerous process.
Microbial Agents and Topical Agresors

With frequency these can contribute to worsen the condition of the patient.There are biochemical agents that intervene on the inflammation and of course anoxia and tissular hypoxia.

When the epidermis is loss, due to traumatis or necrosis, an area that is delimited, depressed and humid is formed. We are talking about an erosion, that does not extend deeper that the vessel cells.

The destruction of the gross of the epidermis and papillary dermis causes a superficial ulcer. The destruction to the middle or internal part of the dermis will cause a deep ulcer.

The erosions heal without a scar. The non-complex superficial ulcers can regenerate if the edges of the skin remain intact. There is a chance of healing with a dark color scar or hyper-pigmented tissue. Deep ulcers normally heal without leaving a scar.

Diabetic foot ulcers

Diabetic foot defines the group of alterations derived from diabetes’s complications that damage the integrity of the skin and usually deeper tissues.

This is the complication that causes the most number of hospitalizations due to diabetes mellitus and it is as well one of the causes for a long hospital stay.

For the patients with diabetes the risk of developing an ulcer is from 15% to 25% at a point during their lives, on some western countries the statistics drop to 7% -10% and a prevalence of 5 to 10 new cases for every thousand diabetics annually.

The partial amputation of an extremity is from 14% to 20% on the patients with diabetic foot, being the first cause for non-traumatic amputation worldwide. The diabetic patient is 10 times more likely to suffer an amputation than the general population.


On the diabetic foot pathology there interrelated factors that intervene in the development of the wound, these can be grouped by:

  • Predisposing Factors.
  • Trigger Factors.
  • Aggravating Factors.

Predisposing Factors

These factors predispose a “healthy foot” to become a “high-risk foot”.

Factor Characteristic

Especially when there is a long evolution of the Diabetes Mellitus, when the patient is older than 45 years, male patients.

Persistent Hyperglycemia is a key element for the development of neuropathy and angiopathy.


It is the main predisposing factor of the diabetic foot ulcers, it is present on 75% to 80% of the patients with Type 1 Diabetis and in 40% to 50% on thepatients with type 2 diabetes with more than 12 years of evolution and in almost 100% of the patients with an evolution of the disease of more than 25 years.

This is caused by many factors; the most talked about is the metabolic cause where an inflammation of the nerves is present due to an excessive accumulation od sorbitol, polyalcohol, generated by sustained hyperglycemia.

Another cause is the glucolysation of the proteins on the neuronal axons, which interfere with the synaptic transmission, and causes an autoimmune inflammation of the nerves, adding neuronal ischemia caused for the damage to the nervous microcirculation.

Neuropathy is irreversible, but its apparition can be retarded by glycemic control.

There are a few types of Neuropathy: sensitive, motor and mixed; if there is a sensitive alteration it can cause the partial or total sensitivity of the foot.

If it is a motor neuropathy it can cause alteration on the foot’s position and biomechanics, that will progressively increment the pressure on specific points and it can cause wounds.


Is really frequent due to the atherosclerosis, that is present more frequently on diabetic patients, when there are microvascular lesions can increment local ischemia, that will worsen other factors such as neuropathic, infectious, and wound healing.

Other Metabolic Issues

Obesity, hypertriglyceridemia and metabolic syndrome, that contributes to alterations on the circulatory paths, due to the processes of atherosclerosis.


Specific to Nephropathy and Peripheral Venous insufficiency that contribute causing hypotrophy of the skin, can lead to have a bigger susceptibility to cutaneous wounds and their chronicity.


Its influence on ulcers is due to the vasoconstriction of the peripheral arteries and the result ischemia of the tissues.


It aggravates the neuropathic alterations.

Trigger Factors

Are the ones that have a direct influence on the wounds, due to the increment of predisposing factors. Usually the triggers are traumatic factors that star the wounds.

Factor Characteristics

Injuries or osteoarticular deformities of the foot, such as hallux valgus, claw toes, Charcot’s foot and all of those that limit the movility of the articulations that increases the amount of pressure on specific points of the foot, that will leas to calluses and hyperkeratosis.


Traumatisms (thermic, chemical or physical), that can be acute or chronic, this is due to the diminishing or even the loss of sensibility due to the patient’s neuropathy, this is the cause that these traumatisms are not perceived.

The most common are: The use of improper shoes and the bad care of calluses and toe nails.

Aggravating Factors

These factors are the ones that interfere on the chronicity of the ulcer and its complications, their presence increments the risk of amputation. The aggravating factors are: Infection & Ischemia.

Factor Characteristics

Is the most frequent due to its increased effects can lead to tissue necrosis, provokes the increase on the size of the wounds.


It contributes to the delay of the regeneration of the tissues and acts directly on the chronicity of the problem.