Progressive vaccinia is a rare cutaneous condition caused by the

vaccinia ''Vaccinia virus'' (VACV or VV) is a large, complex, enveloped virus belonging to the poxvirus family. It has a linear, double-stranded DNA genome approximately 190 kbp in length, which encodes approximately 250 genes. The dimensions of the ...

virus, characterized by painless but progressive necrosis and ulceration.

Presentation

Complications

Opportunistic

fungal A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

, protozoal, or

bacterial Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were amon ...

infections and the vaccinia virus itself may lead to septic shock and disseminated intravascular coagulation, in addition to necrosis and ulcerated skin tissue. Some of these tissues may eventually become large, requiring not only a skin graft but surgical removal of the destroyed tissue, in order to avoid graft-versus-host disease in organ transplanted patients, in whom immunosuppressive therapy would otherwise have to be discontinued to allow healing of the wound.

Pathophysiology

Vaccinia is introduced into the skin by means of multiple punctures of a bifurcated needle. The virus replicates in the basal layer and disseminates from cell to cell, causing necrosis and the formation of fluid-filled vesicles. Nonetheless, the initial spread of the virus is slowed by innate antiviral mechanisms, and, by the second week, the cell-mediated immune response begins to eliminate infected cells. Neutrophils, macrophages, and lymphocytes infiltrate the inoculation site, forming a confluent pustule and releasing cytokines and chemokines that cause

hyperemia Hyperaemia (also hyperemia) is the increase of blood flow to different tissues in the body. It can have medical implications but is also a regulatory response, allowing change in blood supply to different tissues through vasodilation. Clinically, ...

and edema in surrounding tissues. This may initially manifest into complaints of malaise and other mild constitutional symptoms, fever, vomiting, and tender enlarged axillary lymph nodes. Some vaccinees develop additional local “satellite” pustules that resolve along with the primary lesion. The virus may gain access to the blood at an early stage, and secondary skin lesions, which follow the same evolution as the inoculation site, may appear across the body. Bacteria, like Staphylococcus aureus, may infect the ulcerated, and necrotic lesions. Coalescent lesions may cover large portions of the body with extensive tissue destruction. Although some vaccinia viruses commonly disseminate through the bloodstream, the ''NYCBOH strain'' reportedly causes only limited viremia in a small percentage of recipients during the period of pustule formation. The inflammatory process reaches its peak by days 10–12 after vaccination and begins to resolve by day 14, with the shedding of the scab and other pustules by day 21. This sequence of events, which simulates the development of smallpox "pock", is known as a “take” reaction. A successful "take" is required for the development of antivaccinia antibody and cell-mediated responses.

Treatment

In addition to a

skin graft Skin grafting, a type of graft surgery, involves the transplantation of skin. The transplanted tissue is called a skin graft. Surgeons may use skin grafting to treat: * extensive wounding or trauma * burns * areas of extensive skin loss du ...

, some medications also work. Among antiviral substances,

cidofovir Cidofovir, brand name Vistide, is a topical or injectable antiviral medication primarily used as a treatment for cytomegalovirus (CMV) retinitis (an infection of the retina of the eye) in people with AIDS. Cidofovir was approved for medical u ...

showed some effect in preliminary studies. Apart from treating opportunistic infections with

anti-viral Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Unlike most antibiotics, antiviral drugs do ...

, and antibiotic medications, for

HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...

or immunocompromised (or at the very least iatrogenic immunosuppression like cancer and autoimmune disease) people, immediate highly active antiretroviral therapy (HAART) in HIV patients and withdrawal of immunosuppressive therapy accompanied by aggressive administration of VIG are given to save the patient's life. Intensive care and supportive treatment are required. VIG is given at up to 10 ml / kg body weight.

Note

References