Sporotrichosis is a disease caused by the infection of the
fungusA fungus is any member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The Fungi are classified as a kingdom that is separate from plants, animals and bacteria...
Sporothrix schenckiiSporothrix schenckii is a thermally dimorphic fungus that can be found world-wide, and is the only active species of the genus Sporothrix....
. This fungal disease usually affects the
skinThe skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system made up of multiple layers of mesodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs. Skin of a different nature exists in amphibians, reptiles, birds...
, although other rare forms can affect the
lungThe lung or pulmonary system is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart...
s,
jointA joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
s,
boneBones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s, and even the
brainThe brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all...
. Because
roseA rose is a perennial flower shrub or vine of the genus Rosa, within the family Rosaceae, that contains over 100 species and comes in a variety of colours. The species form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp prickles...
s can spread the disease, it is one of a few diseases referred to as
rose-thorn or
rose-gardeners' disease.
Because
S. schencki is naturally found in soil,
hayHay is a generic term for grass or legumes that have been cut, dried, and stored for use as animal feed, particularly for grazing animals like cattle, horses, goats, and sheep. Hay is also fed to pets such as rabbits and guinea pigs...
, sphagnum moss, and plants, it usually affects
farmerA farmer is a person who raises living organisms for food or raw materials.- Definition :The term farmer usually applies to a person who grows field crops, and/or manages orchards or vineyards, or raises livestock or poultry such as chicken and cows...
s, gardeners, and agricultural workers. It enters through small cuts and abrasions in the skin to cause the infection. In case of sporotrichosis affecting the lungs, the fungal spores enter through the respiratory pathways. Sporotrichosis can also be acquired from handling cats with the disease; it is an occupational hazard for veterinarians.
Sporotrichosis progresses slowly - the first symptoms may appear 1 to 12 weeks (average 3 weeks) after the initial exposure to the fungus. Serious complications can also develop in patients who have a compromised
immune systemAn immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumour cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
.
Forms and symptoms of sporotrichosis
- Cutaneous or skin sporotrichosis
- This is the most common form of this disease. Symptoms of this form includes nodular lesion
A lesion is any abnormal tissue found on or in an organism, usually damaged by disease or trauma. Lesion is derived from the Latin word laesio which means injury.-Causes of lesions:...
s or bumps in the skin, at the point of entry and also along lymphLymph is the interstitial fluid found between the cells of the human body. It enters the lymph vessels by filtration through pores in the walls of capillaries...
nodes and vessels. The lesion starts off small and painless, and ranges in color from pink to purple. Left untreated, the lesion becomes larger and look similar to a boilBoil is a skin disease caused by the infection of hair follicles, resulting in the localized accumulation of pus and dead tissue. Individual boils can cluster together and form an interconnected network of boils called carbuncles....
and more lesions will appear, until a chronic ulcer develops.
- Usually, cutaneous sporotrichosis lesions occur in the finger, hand, and arm.
- This rare form of the disease occur when S. schenckii spores are inhaled. Symptoms of pulmonary sporotrichosis include productive cough
A cough , in medicine, is a sudden and often repetitively occurring defense reflex which helps to clear the large breathing passages from excess secretions, irritants, foreign particles and microbes...
ing, nodules and cavitations of the lungs, fibrosisFibrosis is the formation or development of excess fibrous connective tissue in an organ or tissue as a reparative or reactive process, as opposed to a formation of fibrous tissue as a normal constituent of an organ or tissue....
, and swollen hilarAbove and behind the cardiac impression is a triangular depression named the hilum, where the structures which form the root of the lung enter and leave the viscus...
lymph nodeA lymph node is an organ consisting of many types of cells, and is a part of the lymphatic system. Lymph nodes are found all through the body, and act as filters or traps for foreign particles. They contain white blood cells that use oxygen to process. Thus they are important in the proper...
s. Patients with this form of sporotrichosis are susceptible to developing tuberculosisTuberculosis is a common and often deadly infectious disease caused by mycobacteria...
and pneumoniaPneumonia is an inflammatory illness of the lung. Frequently, it is described as lung parenchyma/alveolar inflammation and abnormal alveolar filling with fluid ....
- Disseminated sporotrichosis
- When the infection spreads from the primary site to secondary sites in the body, the disease develops into a rare and critical form called disseminated sporotrichosis. The infection can spread to joints and bones (called osteoarticular sporotrichosis) as well as the central nervous system
The central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of bilaterian animals—that is, all animals more advanced than sponges or jellyfish. In vertebrates, the central nervous system is enclosed in the meninges. It contains...
and the brain (called sporotrichosis meningitis).
- The symptoms of disseminated sporotrichosis include weight loss, anorexia
Anorexia is the decreased sensation of appetite...
, and appearance of bony lesions.
Sporotrichosis in animals
Sporotrichosis can be diagnosed in domestic and wild mammals. In veterinary medicine it is most frequently seen in cats and horses. Cats have a particularly severe form of cutaneous sporotrichosis and also can serve as a source of zoonotic infection to persons who handle them and are exposed to exudate from skin lesions.
Diagnosis
Sporotrichosis is a
chronicIn medicine, a chronic disease is a disease that is long-lasting or recurrent. The term chronic describes the course of the disease, or its rate of onset and development. A chronic course is distinguished from a recurrent course; recurrent diseases relapse repeatedly, with periods of remission in...
disease with slow progression and often subtle symptoms. It is difficult to diagnose, as many other diseases share similar symptoms and therefore must be ruled out.
Patients with sporotrichosis will have antibody against the fungus S. schenckii, however, due to variability in sensitivity and specificity, it may not be a reliable diagnosis for this disease. The confirming diagnosis remains culturing the fungus from the skin,
sputumSputum is matter that is expectorated from the respiratory tract, such as mucus or phlegm, mixed with saliva, which can then be spat from the mouth. It is usually associated with air passages in diseased lungs, bronchi, or upper respiratory tract...
,
synovial fluidSynovial fluid is a thick, stringy fluid found in the cavities of synovial joints. With its sperm-like consistency , synovial fluid reduces friction between the articular cartilage and other tissues in joints to lubricate and cushion them during movement.-Overview:The inner membrane of synovial...
, and
cerebrospinal fluidCerebrospinal fluid , Liquor cerebrospinalis, is a clear bodily fluid that occupies the subarachnoid space and the ventricular system around and inside the brain. In essence, the brain "floats" in it....
.
Cats with sporotrichosis are unique in that the exudate from their lesions may contain numerous organisms. This makes cytological evaluation of exudate a valuable diagnostic tool in this species. Exudate is pyogranulomatous and phagocytic cells may be packed with yeast forms. These are variable in size, but many are cigar-shaped.
Prevention
The majority of sporotrichosis cases occur when the fungus is introduced through a cut or puncture in the skin while handling vegetation containing the fungal spores. Prevention of this disease includes wearing long sleeves and gloves while working with soil, hay bales, rose bushes, pine seedlings, and sphagnum moss.
Treatment
Treatment of sporotrichosis depends on the severity and location of the disease. The following are treatment options for this condition:
- Saturated potassium iodide
Potassium iodide is an inorganic compound with formula KI. This white salt is the most commercially significant iodide compound, with approximately 37,000 tons produced in 1985. It is less hygroscopic than sodium iodide, making it easier to work with...
solution
- Although its mechanism is unknown, oral application of potassium iodide in droplet form can cure cutaneous sporotrichosis. This usually requires 3 to 6 months of treatment.
- Itraconazole
Itraconazole , invented in 1984, is a triazole antifungal agent that is prescribed to patients with fungal infections...
(Sporanox) and fluconazoleFluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. In a bulk powder form, it appears as a white crystalline powder, and it is very slightly soluble in water and soluble in alcohol. It is commonly marketed under the trade...
- These are antifungal drugs. Itraconazole is currently the drug of choice and is significantly more effective than fluconazole. Fluconazole should be reserved for patients who cannot tolerate itraconazole.
- Amphotericin B
Amphotericin B is a polyene antifungal drug, often used intravenously for systemic fungal infections...
- This antifungal medication is delivered intravenously. Many patients, however, cannot tolerate Amphotericin B due to its potential side effects of fever, nausea, and vomiting.
- In case of sporotrichosis meningitis, the patient may be given a combination of Amphotericin B and 5-fluorocytosine/Flucytosine
Flucytosine, or 5-fluorocytosine, a fluorinated pyrimidine analogue, is a synthetic antimycotic drug.It is structurally related to the cytostatic fluorouracil and to floxuridine. It is available in oral and in some countries also in injectable form. A common brand name is Ancobon. The drug is...
.
- Surgery
Surgery is a medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, to help improve bodily function or appearance, or sometimes for some other reason...
- In cases of bone infection and cavitatory nodules in the lungs, surgery may be necessary.
Complications
Sporotrichosis can develop into other diseases, including
cellulitisCellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters,...
,
sarcoidosisSarcoidosis , also called sarcoid or Besnier-Boeck disease, is a multisystem granulomatous inflammatory disease characterized by non-caseating granulomas . The cause of the disease is still unknown...
, and
tuberculosisTuberculosis is a common and often deadly infectious disease caused by mycobacteria...
.
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