Atypical wounds, also known as wounds of unknown etiology, are wounds caused by conditions or diseases that don’t typically form a wound, like inflammations, infections, malignancies, chronic illnesses or genetic disorders. Atypical wounds can also stem from rare uncommon causes, or occur with an abnormal presentation or location.
Atypical wounds usually mimic arterial and venous ulcers, most often occurring on the lower limbs (especially below the knee or on the sole of foot). The following is a brief description of the types, causes and symptoms of the most frequent atypical wounds:
Pyoderma gangernosum: This is a rare inflammatory condition of skin cell death and destruction due to an unknown cause. It causes large painful sores (ulcers) to form, mainly on legs, but can also happen anywhere on the body as a secondary complication of any skin cut or trauma.
Bullous pemphigoid: This is a rare autoimmune inflammatory condition of unknown cause, wherein the immune system forms antibodies against its own tissue. These antibodies are formed against the junction between the upper and lower skin layers (dermo-epidermal junction); leading to large clear fluid-filled blisters formation that are not easy to rupture. If they do rupture, the blisters can become painful and sensitive. These occur most often on the abdomen, groin, inner thighs and arms.
Cryoglobulinemia: This is a systemic inflammation mainly affecting the kidneys, joints and skin. It is caused by deposits of immune complexes containing cryglobulin. This leads to itchy, small red skin lesions and ulcers (especially on legs), and causes joint pain in fingers, hands, knees and ankles, bloody urine, general weakness, decreased sensation in some of the extremities and abdominal pain.
Vasculitis: An inflammatory condition of the blood vessels due to unknown origin. Vasculitis can be systemic (throughout the body) or localized, and can affect all types of blood vessels. Thus, the presentation varies from mild redness and irritation to occlusion of blood vessels and ischemia of the affected area.
Blastomycosis: A rare disease that results from breathing a fungus from wood or soil. It presents with flu-like symptoms that include fever, chills, fatigue, headache and a dry cough that lasts for a few days. However, it can also present with more severe symptoms of bacterial pneumonia (high fever, cough with sputum, night sweats and chest pain) or acute respiratory distress syndrome (shortness of breath and rapid breathing). These symptoms can be accompanied by skin lesions or, less frequently, by bone and joint pain.
Atypical mycobacterial infection: This was previously known as Non-tuberculous mycobacterial infection, caused by mycobacterium avium and mycobacterium scrofulaceum. This presents with abnormally enlarged lymph nodes of the jaw and neck areas, and is associated with fever, general weakness, joint and bone pain.
Skin squamous cell carcinoma: A common cancer of the skin, associated with excessive exposure to sunlight or arsenic. Small, red ulcerations commonly appear on hands and lower part of face.
Basal cell carcinoma: This is the most common type of skin cancer, which typically occurs on sun exposed areas of the body. This appears as centrally ulcerated round skin lesions on the hands and face, and may appear as very small red dots on skin.
Kaposi sarcoma: This is the most common cancer in AIDS patients or advanced HIV-infection cases. It presents with multiple brown to pinkish skin lesions of different sizes, shapes and depths, mainly on the face, neck, legs and mucosa of mouth and the gastrointestinal system. It can also present with enlarged lymph nodes, pain with swallowing and walking.
Hereditary and Genetic Wounds
Scleroderma: This is a chronic systemic disease of progressive inflammation and tissue fibrosis, and includes occlusion of small blood vessels. This presents with skin tightening, discoloration, itching and Raynaud's phenomenon (a constriction of small blood vessels of the hands resulting in painful, cold and bluish fingers). Scleroderma can also cause difficulty eating, heartburn, constipation that alternates with diarrhea, a dry cough, joint pain and muscle weakness.
Dermatitis artefacta: This condition is caused by multiple genetic and psychological factors. It presents with multiple superficial, self-inflicted skin lesions of variable shape, size and depth on accessible areas like the face, arms and abdomen. Patients will often deny inflicting these wounds. Usually the patient has a history of chronic skin conditions and personal or familial history of psychiatric conditions.
Sickle cell anemia: This inherited form of anemia is due to abnormally crescent-shaped red blood cells that cannot deliver a sufficient amount of oxygen to the cells. These blood cells can easily clot and block blood vessels, causing severe painful ischemic attacks in the affected areas or organs.
Epidermolysis bullosa: This rare inherited disease of the skin can manifest with very fragile skin and blisters that can easily rupture in response to friction from clothing, trauma or routine activities.
Wounds of External Cause
Brown recluse spider: Initially the spider bite may go unnoticed, as it is not painful, but over the next six to eight hours it can progress to severe pain, itchiness, and a clear fluid-filled cyst with a red surrounding border. Additionally, there may be one or more accompanying symptoms like nausea, vomiting, diarrhea, fever, seizures or coma.
Radiation necrosis: This condition is usually secondary to treatment for preexisting central nervous system tumors using radiotherapy or radio surgery. The existing tumor makes the surrounding tissue more vulnerable to radiation, which leads to necrosis (destruction of cells), causing more damage. New symptoms may include memory loss, and motor or sensory dysfunction.
The risk for atypical wounds is usually higher in elderly people with weak immune systems,and is associated with preexisting chronic medical illness, infections, inflammations or tumors. Taking many prescribed medications and leading an unhealthy lifestyle can also increase the risk for developing atypical wounds.
It is very challenging to treat atypical wounds, as it usually requires a team of physicians from different disciplines or areas of specialization. All treatment plans begin with identifying the causing agent(s) of the wound as early as possible. Treating or removing the underlying cause, along with proper wound care, improved lifestyle, psychological therapy (when needed), and the correct medication can successfully resolve almost any case of atypical wounds.