Progressive vaccinia is a rare cutaneous condition caused by the vaccinia virus, characterized by painless but progressive necrosis and ulceration.

Presentation

Complications

Opportunistic fungal,

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

l, or bacterial infections and the vaccinia virus itself may lead to septic shock and

disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts o ...

, 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 Graft-versus-host disease (GvHD) is a syndrome, characterized by inflammation in different organs. GvHD is commonly associated with bone marrow transplants and stem cell transplants. White blood cells of the donor's immune system which remain wit ...

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 A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

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 Inoculation is the act of implanting a pathogen or other microorganism. It may refer to methods of artificially inducing immunity against various infectious diseases, or it may be used to describe the spreading of disease, as in "self-inoculati ...

site, forming a confluent pustule and releasing cytokines and chemokines that cause hyperemia and

edema Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...

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 ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive ...

, 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, some medications also work. Among antiviral substances, cidofovir showed some effect in preliminary studies. Apart from treating opportunistic infections with anti-viral, and

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

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 immu ...

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