Lymphangitis is an acute inflammation of the lymphatic vessels, usually involving a single extremity after skin trauma. Bacterial infection is the most common cause, whereas insect stings, parasitic and fungal infections, but also malignant diseases may trigger this condition. Swelling, tenderness and various skin lesions may be seen on the affected limb. The diagnosis is made by clinical and microbiological criteria, while treatment depends on the underlying cause.
The main clinical features of lymphangitis are the development of erythematous and warm streaks that follow the lymphatic channels on the affected extremity . Lesions and their distinguishing features may significantly aid in making an initial diagnosis. Francisella tularensis manifests with a painful chancre at the site of initial lesion and is followed by intense proximal lymphandenitis that is painful and tender . Purulent discharge from the lesion may also be observed . Sporotrichosis appears as a painless, indurated, erythematous papule that is seen approximately 1-4 weeks after inoculation, with eventual formation of ulcerating nodules . Leishmaniasis shares similar clinical features to Sporotrichosis. The erythematous ulcerating papules, however, are pruritic and appears up to 12 weeks after the bite of a sandfly in endemic areas . Purulent discharge may be observed in nocardiosis as well .,while systemic symptoms such as fever, chills, headaches and tachycardia develop in more severe cases . In rare cases of granulomatous lymphangitis, scrotal edema in the pediatric population may be observed . Lymphangitis carcinomatosa may present with a myriad of symptoms, most common being dyspnea and cough ., suggesting lung cancer as a potential etiology.
A detailed patient history and a thorough physical examination are the most important parts of the diagnostic workup. Information regarding recent travel, onset of symptoms and occupancy are of vital importance in determining the underlying cause, whereas clinical criteria - presence of red streaks and edema, are sufficient to make an initial diagnosis. Although microbial confirmation is considered as unnecessary ., it is very important to determine the underlying cause through various microbiological tests. Culture of the sample obtained from the lesion may be sufficient, whereas serology and PCR (which is now being considered as superior to other methods, primarily due to its speed) may be performed as well. Laboratory findings commonly reveal leukocytosis .
Antimicrobial agents are considered as mainstay of therapy and are often administered empirically, but optimal therapeutic strategies can be determined only if the microbial pathogen is identified . Initial regimens include beta-lactam agents such as penicillin, amoxicillin, ceftriaxone, dicloxacillin or cephalexin, since the most common cause is group B Streptococcus . If the presumed agent is S. aureus and if there is reasonable suspicion for methicillin-resistant (MRSA) strains, vancomycin 1g q12h shouls be administered . Itraconazol and other azole agents are used if Sporotrichosis is suspected, whereas diethylcarbamazine (DEC) is first-line therapy in lymphatic filariasis . Nocardiae respond effectively to trimethoprim-sulfamethoxazole, as does mycobacterium marinum, while sodium stibogluconate and other antimony derivatives have good activity against Leishmania  .
The prognosis is good with early and appropriate therapy, but numerous complications may arise. Progression of the infection into tendons, bones, joints and bursae may be seen, whereas immunocompromised patient can develop a more severe course of illness due to potential dissemination into distant issues . If bacterial microorganisms are not destroyed locally (which is why lymphadenitis is most often present together with lymphadenitis), they can reach the venous and systemic circulation and cause bacteremia or even sepsis, a potentially life-threatening condition . For these reasons, a prompt diagnosis is necessary.
Numerous causes of lymphangitis have been identified, the most common being bacterial microorganisms such as group A streptococci, Staphylococcus aureus, Pasteurella multocida and Spirillum minus . Although various nontuberculous mycobacteria (NTM) can cause this type of infection, Mycobacterium marinum is most frequently identified in the setting of nodular lymphangitis . The history of trauma and subsequent exposure to aqueous environments (lakes, oceans and swimming pools) are thought to be the mode of inoculation and infection . Wuchereria bancrofti, Brugia malayi and Brugia timori are causative agents of lymphatic filariasis, one of the most prevalent forms of lymphatic disease . Sporothrix schenckii - a dimorphic fungus, is considered as the most common subcutaneous mycosis ., and is one of the most common causes of nodular lymphaginitis . Leishmania species and Nocardia braziliensis are somewhat less common causes of lymphangitis, whereas Rickettisal species (primarily R. sibirica) was recently discovered as a cause in some parts of the world . Noninfectious causes include arthropod bites, malignant diseases of the lung, breast, kidney, GI tract, thyroid and the cervix (known as lymphangitis carcinomatosa)  ., while granulomatous lymphangitis that appears in the setting of autoimmune diseases such as Melkersson-Rosenthal syndrome, but also Crohn disease have has been established as a potential cause . In fact, lymphangitis has shown to be an important pathological event in Crohn disease, but the underlying cause of lymphatic changes in this disease remain to be solidified .
Lymphangitis is considered as a rare complication of skin and soft tissue infections, developing in less than 0.2% of cellulitis cases . On the other hand, more than 120 million individuals in tropical and sub-tropical parts of the world are thought to be infected by filarial parasites and more than 40 million suffer from serious and debilitating disease ., with mosquitoes being the main vectors of transmission . Previous trauma is considered as the most important risk factor for development of lymphangitis . Abrasions, animal scratch (especially by cats, who harbor agents such as Sporothrix schenckii) ., but also insect bites and thorn puncture are most frequently mentioned modes of trauma . Various occupational risk factors have been established, depending on the underlying microbial agent. Mycobacterium marinum infection is most frequently seen in fish-handlers and those involved in marine-related hobbies ., whereas Sporothrix schenckii and Nocardia braziliensis infections occur in farmers, gardeners and forestry workers, as these microorganisms are found in soil and wood . Leishmaniasis is transmitted by a vector, sandfly, and travel to endemic areas - subtropical parts of Africa and Asia, but also South America (Brazil), is necessary in order to contract this protozoa . Rickettsia sibirica is primarily found on the Mediterranean coast .
The pathogenesis of lymphangitis almost exclusively involves an inflammatory reaction of the immune system to the microbial agent, whether it is parasitic, fungal or bacterial. After trauma that leads to breaks in the skin, the pathogen migrates into the lymphatic vessels and triggers dilation of endothelial capillaries and proliferation of proinflammatory lymphocytes as a result of intense cytokine stimulation . Because of capillary dilation and production of cytokines, fluid accumulation in the interstitium occurs and leads to edema and local tenderness. If the microorganisms attempt to disseminate to other tissues via the lymphatic vessels, inflammation of the lymph nodes (lymphadenitis) proximal to the site of infection is readily observed, as the immune system attempts to resolve the infection .
Lymphangitis is associated with skin trauma and subsequent exposure to microorganisms through either occupational exposures or travel to endemic areas, implying that proper wound care may significantly reduce the incidence of this condition. The use of repellents when traveling may also provide some protection against sandflies and mosquitoes, the principal vectors of leishmaniasis and filariasis, respectively.
Lymphangitis is a condition that implies inflammation of the lymphatic channels, which most commonly occurs as a result of an infection ., but non-infectious causes have been identified as well. Group A streptococci are considered as the most frequently isolated bacterial pathogens, followed by Staphylococcus aureus, Pasteurella multocida, Nocardia braziliensis, Mycobacterium marinum, Francisella tularensis and Spirillum minus  . Additionally, both fungal (Sporothrix schenckii) and parasitic (Leishmania species and filarial parasites including Wuchereria bancrofti and Brugia malayi) microorganisms have been identified as important causes . Malignant diseases that cause lymphangitis carcinomatosa (a distinct clinical entity characterized by metastatic cancer spread through the lymphatic system, thus causing inflammation), various autoimmune diseases including Crohn disease and insect bites are established non-infectious causes of lymphangitis   . Epidemiology studies suggest that the mode of infection and pathogenesis almost always includes some form of skin trauma, such as abrasions, animal scratch (especially by cats, who are known vectors of Sporothrix schenckii) and punctures by thorns or insects ., followed by inoculation of the harmful pathogen through the damaged skin. Various occupational risk factors have been determined for some pathogens - marine hobbies and work are associated with Mycobacterium marinum, whereas forestry and garden work prones individuals to Nocardia braziliensis and Sporothrix schenckii infection,as they are readily recovered from soil . South America and subtropical parts of Asia and Africa are considered as endemic regions for Leishmania and filarial parasites, suggesting that travel to these areas is a risk factor as well . The clinical presentation may vary in terms of incubation period and onset of symptoms, but generally includes edema, tenderness and presence of erythematous streaks that follow lymphatic tissues, as well as different skin lesions, including macules, papules, erosions or ulcers . Proximal lymphadenitis is not uncommon,as the immune system attempts to cease further microbial dissemination. In most cases, either a lower or upper extremity is involved. Nodular lymphangitis is a distinct condition caused by a limited number of pathogens (Mycobacterium marinum, Sporothrix schenckii, Nocardia braziliensis, Francisella tlarensis and Leishmania braziliensis), manifesting with erythematous papules and nodules that develop along the subcutaneous and dermal lymphatic drainage pathways  . It is vital to obtain a detailed patient history including information regarding recent trauma and travel to endemic areas and an initial diagnosis can be made during physical examination. Various microbiological studies may be performed (culture, serology, polymerase chain reaction - PCR) and in cases where the cause remains undetermined, computed tomography (CT) of the chest and abdomen should be done in order to exclude malignant disease. Treatment depends on the underlying cause, which may include antimicrobial, antifungal, antiparasitic and chemotherapy, respectively. The prognosis is good with appropriate therapy, but it is important to make the diagnosis early on, as dissemination and hematogenous spread can lead to sepsis in the case of bacterial etiology .
Lymphangitis is a medical term that denotes inflammation of the lymphatic channels, which most commonly occurs as a result of an infection. Bacterial microorganisms (group B streptococci, staphylococci and several other) are considered as primary pathogens, whereas certain fungi that invade the skin (such as Sporothrix schenckii) and parasites (Leishmania sp. and filariae) are recognized microorganisms as well. Some of these organisms are endemic in certain parts of the world (South America or tropical parts of Asia and Africa), implying that travel to these areas poses a significant risk for infection. In rare cases, lymphangitis may be caused by metastatic tumors of virtually any type of cancer (in which case the term lymphangitis carcinomatosa is used), or by certain autoimmune conditions such as Crohn disease. The pathogenesis of lymphangitis invariably starts with some form of trauma that causes breaks in the skin through which a microorganism can reach the subcutaneous tissues. Soon after, an extensive inflammatory reaction is triggered and results in dilation of the capillaries with subsequent accumulation of fluid in the intercellular space. As the microorganisms reach the lymphatic system, they are targeted by the immune system in the attempt to eradicate them. These events manifest with various symptoms, most common being the presence of red streaks on the skin that follow the route of the lymphatic vessels, usually in close proximity of the initial skin trauma. Enlargement and inflammation of the proximal lymph nodes (lymphadenitis) is frequently observed, together with various skin lesions. In most cases, these streaks appear on an arm or leg, near the site of initial breaks in the skin. The diagnosis can be made by clinical findings and initial antibiotic treatment may be started immediately, as the presumed cause is group B streptococci. However, in order to avoid the growing trend of antimicrobial resistance, it is essential to determine the underlying pathogen, which can be performed through cultures from samples obtained from the wound and polymerase chain reaction (PCR), a procedure that identifies microbial DNA in the sample. Once the diagnosis is confirmed, treatment depends on the pathogen responsible and may include antibiotics, antifungals or antiparasitic agents. The global burden of lymphangitis in general is not known, but it is estimated that more than 100 million individuals are suffering from lymphatic filariasis, with more than 40 million being severely impaired by this disease. The prognosis of lymphangitis is good with appropriate therapy, but because dissemination of the infection to other tissues (which may even lead to sepsis) may result in poorer outcomes and disability, it is imperative to make an early diagnosis.