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What is Chancroid and explain in detail?
Chancroid ( SHANG-kroyd) is a bacterial sexually transmitted infection characterized by painful sores on the genitalia. Chancroid is known to spread from one individual to another solely through sexual contact. However, there have been reports of accidental infection through another route which is by the hand. While uncommon in the western world, it is the most common cause of genital ulceration worldwide.

Signs and symptoms
These are only local and no systemic manifestations are present.
The ulcer characteristically:

Ranges in size dramatically from 3 to 50 mm (1/8 inch to 2 inches) across
Is painful
Has sharply defined, undermined borders
Has irregular or ragged borders, described as saucer-shaped.
Has a base that is covered with a gray or yellowish-gray material
Has a base that bleeds easily if traumatized or scraped
Painful swollen lymph nodes occur in 30–60% of patients.
Dysuria (pain with urination) and dyspareunia (pain with intercourse) in femalesAbout half of infected men have only a single ulcer. Women frequently have four or more ulcers, with fewer symptoms. The ulcers are typically confined to the genital region most of the time.
The initial ulcer may be mistaken as a "hard" chancre, the typical sore of primary syphilis, as opposed to the "soft chancre" of chancroid.Approximately one-third of the infected individuals will develop enlargements of the inguinal lymph nodes, the nodes located in the fold between the leg and the lower abdomen.Half of those who develop swelling of the inguinal lymph nodes will progress to a point where the nodes rupture through the skin, producing draining abscesses. The swollen lymph nodes and abscesses are often referred to as buboes.

Complications
Extensive lymph node inflammation may develop.
Large inguinal abscesses may develop and rupture to form draining sinus or giant ulcer.
Superinfection by Fusarium and Bacteroides. These later require debridement and may result in disfiguring scars.
Phimosis can develop in long-standing lesion by scarring and thickening of foreskin, which may subsequently require circumcision.

Sites For Chancroid Lesions
Males
Internal and external surface of prepuce.
Coronal sulcus
Frenulum
Shaft of penis
Prepucial orifice
Urethral meatus
Glans penis
Perineum area

Females
Labia majora is most common site. "Kissing ulcers" may develop. These are ulcers that occur on opposing surfaces of the labia.
Labia minora
Fourchette
Vestibule
Clitoris
Perineal area
Inner thighs

Causes
Chancroid is a bacterial infection caused by the fastidious Gram-negative streptobacillus Haemophilus ducreyi. This pathogen is highly infectious. It is a disease found primarily in developing countries, most prevalent in low socioeconomic groups, associated with commercial sex workers.Chancroid, caused by H. ducreyi has infrequently been associated with cases of Genital Ulcer Disease in the US but has been isolated in up to 10% of genital ulcers diagnosed from STD clinics in Memphis and Chicago.Infection levels are very low in the Western world, typically around one case per two million of the population (Canada, France, Australia, UK and US). Most individuals diagnosed with chancroid have visited countries or areas where the disease is known to occur frequently, although outbreaks have been observed in association with crack cocaine use and prostitution.Chancroid is a risk factor for contracting HIV, due to their ecological association or shared risk of exposure, and biologically facilitated transmission of one infection by the other. Approximately 10% of people with chancroid will have a co-infection with syphilis and/or HIV.

Pathogenesis
H. ducreyi enters skin through microabrasions incurred during sexual intercourse. The incubation period of H. ducreyi infection is 10 to 14 days after which there is progression of the disease. A local tissue reaction leads to development of erythomatous papule, which progresses to pustule in 4–7 days. It then undergoes central necrosis to ulcerate.

Diagnosis
Variants
Some of clinical variants are as follows.

Laboratory findings
From bubo pus or ulcer secretions, H. ducreyi can be identified using special culture media; however, there is a <80% sensitivity. PCR-based identification of the organisms is available, but none in the United States are FDA-cleared. Simple, rapid, sensitive and inexpensive antigen detection methods for H. ducreyi identification are also popular. Serologic detection of H. ducreyi uses outer membrane protein and lipooligosaccharide. Most of the time, the diagnosis is based on presumptive approach using the symptomatology which in this case includes multiple painful genital ulcers.

Differential diagnosis
Despite many distinguishing features, the clinical spectrums of following diseases may overlap with chancroid:
Primary syphilis
Genital herpesPractical clinical approach for this STI as Genital Ulcer Disease is to rule out top differential diagnosis of Syphilis and Herpes and consider empirical treatment for Chancroid as testing is not commonly done for the latter.

Comparison with syphilis
There are many differences and similarities between the conditions syphilitic chancre and chancroid:
SimilaritiesBoth originate as pustules at the site of inoculation, and progress to ulcerated lesions
Both lesions are typically 1–2 cm in diameter
Both lesions are caused by sexually transmissible organisms
Both lesions typically appear on the genitals of infected individuals
Both lesions can be present at multiple sites and with multiple lesionsDifferencesChancre is a lesion typical of infection with the bacterium that causes syphilis, Treponema pallidum
Chancroid is a lesion typical of infection with the bacterium Haemophilus ducreyi
Chancres are typically painless, whereas chancroid are typically painful
Chancres are typically non-exudative, whereas chancroid typically have a grey or yellow purulent exudate
Chancres have a hard (indurated) edge, whereas chancroid have a soft edge
Chancres heal spontaneously within three to six weeks, even in the absence of treatment
Chancres can occur in the pharynx as well as on the genitals

Prevention
Chancroid spreads in populations with high sexual activity, such as prostitutes. Use of condom, prophylaxis by azithromycin, syndromic management of genital ulcers, treating patients with reactive syphilis serology are some of the strategies successfully tried in Thailand. Also, treatment of sexual partners is advocated whether they develop symptoms or not as long as there was unprotected sexual intercourse with the patient within 10 days of developing the symptoms.

Treatment
For the initial stages of the lesion, cleaning with soapy solution is recommended and sitz bath may be beneficial. Fluctuant nodules may require aspiration. Treatment may include more than one prescribed medication.

Antibiotics
Macrolides are often used to treat chancroid. The CDC recommendation is either a single oral dose (1 gram) of azithromycin, a single IM dose (250 mg) of ceftriaxone, oral (500 mg) of erythromycin three times a day for seven days, or oral (500 mg) of ciprofloxacin twice a day for three days. Due to a paucity of reliable empirical evidence it is not clear whether macrolides are actually more effective and/or better tolerated than other antibiotics when treating chancroid