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.
Tissue level studies indicate that bile is an important route of excretion. Significant levels have been demonstrated in the majority of body tissues. Although lincomycin appears to diffuse in the cerebrospinal fluid (CSF), levels of lincomycin in the CSF appear inadequate for the treatment of meningitis. Biosynthesis
Lincomycin is an antibiotic classified as a member of the lincosamide class, which typically features a L-proline amino acid derivative linked through amide group with an eight-carbon aminothio sugar. The two units 4-propyl-L-proline and the amino-octose, are each synthesized separately, and are then condensed by LmbD protein, and then further postcondensation reactions involving cleaving of mycothiol, deacetylation, and S-methylation finally yield lincomycin. The biosynthesis of the amino acid moiety of lincomycin, starts with tyrosine which is transformed to 4-propyl-L-proline by the consecutive action of LmbB1, LmbB2, LmbW, LmbA and LmbX proteins. 4-Propyl-L-proline is activated by LmbC and loaded into LmbN, a bifunctional peptidyl carrier protein, and is ready for condensation by LmbD. The biosynthetic pathway for production of the amino-octose moiety is almost fully elucidated although the order of the steps still needs further research. Condensation through a transaldolase (LmbR) of ribose 5-phosphate (C5) with fructose 6-phosphate or sedoheptulose-7-phosphate (providing a C3 unit) forms the octose (C8). Further transformations involving isomerization (LmbN), 1-phosphorylation (LmbP), 8-dephosphorylation (LmbK), guanosine diphosphate attachment at position 1 (LmbO), 4-epimerization (LmbM), 6-oxidation (LmbL), amination (LmbS), imine reduction (LmbZ) and 8-reduction, are performed to construct the amino-octose unit. LmbT protein exchange GDP by ergothioneine and the condensation with 4-propyl-L-proline and catalysed by LmbD can occur.