Pathergy is a skin condition in which a minor trauma such as a bump or bruise leads to the development of skin lesions or ulcers that may be resistant to healing. Pathergy can also lead to ulcerations at the site of surgical incisions. Pathergy is seen with both

Behçet's disease Behçet's disease (BD) is a type of inflammatory disorder which affects multiple parts of the body. The most common symptoms include painful sores on the mucous membranes of the mouth and other parts of the body, inflammation of parts of the e ...

and

pyoderma gangrenosum Pyoderma gangrenosum is a rare, inflammatory skin disease where painful pustules or nodules become ulcers that progressively grow. Pyoderma gangrenosum is not infectious. Treatments may include corticosteroids, ciclosporin, infliximab, or cana ...

. A highly similar phenomenon known as the

Koebner phenomenon The Koebner phenomenon or Köbner phenomenon (, ), also called the Koebner response or the isomorphic response, attributed to Heinrich Köbner, is the appearance of skin lesions on lines of trauma. The Koebner phenomenon may result from either a ...

occurs in

autoimmune diseases An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...

such as

psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...

and

systemic lupus erythematosus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...

, among others. Doctors looking toward a diagnosis of Behçet's disease may attempt to induce a pathergy reaction with a test known as a "skin prick test".http://www.jimmunol.org/content/177/9/6415.full.pdf The inflammation and ulceration that occurs as a result of pathergy in pyoderma gangrenosum often responds to systemic steroid therapy. The pathergy reaction is a unique feature of Behçet's disease and, according to the International Study Group for Behcet's Disease, is among the major criteria required for the diagnosis. Different positive pathergy reaction rates in BD have been reported worldwide. When BD-positive groups are studied for pathergy reaction, the pathergy-positive and pathergy-negative BD groups showed a similar male: female ratio, age at disease onset, and mean disease duration. They also exhibited similar

HLA-B51 HLA-B51 (B51) is an HLA- B serotype. The serotype identifies the more common HLA-B*51 gene products. B51 is a split antigen of the broad antigen B5, and is a sister serotype of B52. There are many alleles within the B*51 allele group. B51 is ...

levels and a similar frequency of oral ulcerations in close family members. The mucocutaneous manifestations, systemic disease expression, and severity score were similar in patients with and without the pathergy reaction. The presence of a positive pathergy reaction is not associated with an increased risk for specific mucocutaneous or systemic manifestations of the disease, and probably does not predict a more severe disease course. It is also important to note that, while a positive pathergy reaction helps to confirm a specific Behçet's disease diagnosis, a negative reaction does not invalidate a BD diagnosis, because the disease process has to be active at the time of the skin prick test to produce a pathergy reaction. Differences in positive/negative pathergy and severity of the reaction depend on disease activity, ethnicity, type of needle used for the prick test, among other factors. Pathergy test is done both orally and cutaneous. Orally, the lower lip is the site of testing. Appearance of any ulcer or papule indicates a positive pathergy reaction. Cutaneous sites are the flexor forearm.

Epidemiology

References

{{reflist Dermatologic terminology

Epidemiology

See also

References