Atypical wounds - characteristics

Wounds that are not arterial, venous, pressure or diabetic foot ulcers are often termed atypical wounds. An accurate diagnosis is imperative for appropriate interventions and successful patient outcomes.
Atypical  wounds - characteristics

The first indication that a wound is not typical (i.e. arterial, venous, pressure, or diabetic foot ulcer) is the lack of response to standard care, as well as the subtle signal in the clinician’s instinct that says, “This is not quite what it looks like it is.”  The challenge then is to dig deeper, to ask more questions, to find out what the real diagnosis is, and then to treat accordingly.  These “atypical” wounds can be divided into the following categories:

  • Infections, both bacterial and fungal
  • Allergic reactions, varying from mild to severe
  • Autoimmune disorders
  • Herpes virus
  • Malignant wounds
  • Miscellaneous wounds

There are several characteristics of a wound that can alert the clinician to think outside the box in making a diagnosis, including the following:

  • Unusual location, for example, what appears to be a venous ulcer but located below the ankle
  • Unusual age of the patient, for example, what appears to be an arterial wound on the toe of a patient who is in the early 20’s, too young to have peripheral arterial disease!
  • An asymmetric lesion
  • Granulation tissue that extends over the wound edge, an indication of cell growth that is out of control
  • Friable granulation tissue, or tissue that bleeds easily when softly rubbed
  • Purple-red color around the ulcer edges, a characteristic termed violaceous
  • Ulcer located in the center of a pigmented lesion
  • History of repeated trauma
  • Rolled out edges
  • Fungating growth, defined as both rapid and exuberant tissue formation that often leads to necrosis of some tissue and vulnerability for infection, usually a sign of malignancy
  • History of radiation therapy, burns, or diabetes
  • No other obvious diagnosis, in which case one has to keep digging for the answer!

During the next weeks, specific atypical diagnoses will be presented, with the pathophysiology, clinical presentation, medical management, and wound management.  In doing so, the following terminology describing integumentary morphology will be used:

  • Macule – a circumscribed, flat, non-palpable lesion, that is flush with the level of surrounding normal skin,  smaller than 10 mm in diameter
  • Patch – a flat, non-palpable lesion that is flush with the level of surrounding normal skin, greater than 10 mm in diameter
  • Papule -  a superficial, circumscribed dome-shaped or flat-topped palpable lesion elevated above the skin surface, less than 10 mm in diameter
  • Plaque – a lesion that rises slightly above the surface of the skin, greater than 1o mm in diameter
  • Nodule – a firm lesion that is thicker or deeper than the average plaque or papule, is palpable as differentiated tissue
  • Vesicle – an elevated lesion that contains clear fluid; less than 10 mm in diameter
  • Bulla – an elevated lesion that contains clear fluid; greater than 10 mm in diameter
  • Pustule – an elevated lesion that contains pus, of any size
  • Urticarial (hives) – an allergic reaction characterized by white fluid-filled blisters (termed wheals) surrounded by erythema (termed flares)
  • Livedo reticularis – a mottled, lace-like purplish discoloration of the skin caused by thrombotic  occlusion of the capillaries that leads to swelling of the venules






It is the author’s prayer that these discussions will help clinicians make accurate diagnoses and initiate appropriate care for improved patient outcomes.

More information is available on diagnosing and treating atypical wounds at the following site:

Hamm RL, Shah JB.  Atypical Wounds. In Hamm R (Ed), Text and Atlas of Wound Diagnosis and Treatment: 2nd edition.  New York: McGraw Hill Education.  2019, 235-268.  Available at