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16-403: The Koebner phenomenon describes skin lesions which appear at the site of injury. It is seen in: A similar response occurs in pyoderma gangrenosum and Behcet's syndrome , and is referred to as pathergy . Rarely Koebner phenomenon has been reported as a mechanism of acute myeloid leukemia dissemination. Warts and molluscum contagiosum are often listed as causing a Koebner reaction, but this

32-442: 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

48-506: A diagnosis of Behçet's disease may attempt to induce a pathergy reaction with a test known as a "skin prick test". 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

64-476: A diagnosis of PG have an alternative diagnosis. In light of this, validated diagnostic criteria have recently been developed for ulcerative pyoderma gangrenosum. In addition to a biopsy demonstrating a neutrophilic infiltrate, patients must have at least 4 minor criteria to meet diagnostic criteria. These criteria are based on histology, history, clinical examination and treatment. First-line therapy for disseminated or localized instances of pyoderma gangrenosum

80-676: A moist environment, so treatment should be carefully evaluated at each stage. Papules that begin as small "spouts" can be treated with Dakin's solution to prevent infection and wound clusters also benefit from this disinfectant. Wet to dry applications of Dakins can defeat spread of interior infection. Heavy drainage can be offset with Coban dressings. Grafting is not recommended due to tissue necrosis. If ineffective, alternative therapeutic procedures include systemic treatment with corticosteroids and mycophenolate mofetil ; mycophenolate mofetil and ciclosporin; tacrolimus; thalidomide ; infliximab ; or plasmapheresis . Pathergy Pathergy

96-687: A type of autoinflammatory disorder , is associated with mutations in the proline-serine-threonine phosphatase-interacting 1 gene ( PSTPIP1 ). Though the cause is not well understood, the disease is thought to be due to immune system dysfunction, and particularly improper functioning of neutrophils . In support of an immune cause, a variety of immune mediators such as interleukin (IL)-8 , IL-1β , IL-6 , interferon (IFN)-γ , granulocyte colony-stimulating factor , tumor necrosis factor alpha , matrix metalloproteinase (MMP)-9 , MMP10 , and elafin have all been reported to be elevated in patients with pyoderma gangrenosum. Also in support of an immune cause

112-546: 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 and pyoderma gangrenosum . A highly similar phenomenon known as the Koebner phenomenon occurs in autoimmune diseases such as psoriasis and systemic lupus erythematosus , among others. Doctors looking toward

128-472: Is by direct inoculation of viral particles. The linear arrangement of skin lesions in the Koebner phenomenon can be contrasted to both lines of Blaschko and dermatomal distributions. Blaschko lines follow embryotic cell migration patterns and are seen in some mosaic genetic disorders such as incontinentia pigmenti and pigment mosaicism . Dermatomal distributions are lines on the skin surface following

144-498: Is systemic treatment with corticosteroids and ciclosporin . Topical application of clobetasol , mupirocin , and gentamicin alternated with tacrolimus can be effective. Pyoderma gangrenosum ulcers demonstrate pathergy , that is, a worsening in response to minor trauma or surgical debridement. Significant care should be taken with dressing changes to prevent potentially rapid wound growth. Many patients respond differently to different types of treatment, for example some benefit from

160-635: Is the finding that at least half of all pyoderma gangrenosum patients suffer from immune-mediated diseases. For instance, ulcerative colitis , rheumatoid arthritis , and monoclonal gammopathies have all been associated with pyoderma gangrenosum. It can also be part of autoinflammatory syndromes such as PAPA syndrome. Marzano et al. (2017) identified a variety of single-nucleotide polymorphisms (SNPs) linked to autoinflammation that were carried, singly or in combination, in subsets of patients with pyoderma gangrenosum, acne and suppurative hidradenitis syndrome ( PASH syndrome ) or isolated pyoderma gangrenosum of

176-578: 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 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

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192-497: The distribution of spinal nerve roots. The rash caused by herpes zoster ( Shingles ) follows such dermatomal lines. The Koebner phenomenon was named after the rather eccentric but renowned German dermatologist Heinrich Koebner (1838–1904). Koebner is best known for his work in mycology . His intense nature is illustrated by the following: in a medical meeting, he proudly exhibited on his arms and chest three different fungus infections, which he had self-inoculated, in order to prove

208-524: The infectiousness of the organisms he was studying. The Koebner phenomenon is the generalized term applied to his discovery that on psoriasis patients, new lesions often appear along lines of trauma. 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 canakinumab . The disease

224-407: 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

240-498: The ulcerative subtype. One hallmark of pyoderma gangrenosum is pathergy , which is the appearance of new lesions at sites of trauma, including surgical wounds. Diagnosis of PG is challenging owing to its variable presentation, clinical overlap with other conditions, association with several systemic diseases, and absence of defining histopathologic or laboratory findings. Misdiagnosis and delayed diagnosis are common. It has been shown that up to 39% of patients who initially received

256-450: Was identified in 1930. It affects approximately 1 person in 100,000 in the population. Though it can affect people of any age, it mostly affects people in their 40s and 50s. There are two main types of pyoderma gangrenosum: Other variations are: The following are conditions commonly associated with pyoderma gangrenosum: A rare syndromic association called pyogenic arthritis, pyoderma gangrenosum and acne syndrome ( PAPA syndrome ),

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