CHANCROID, LYMPHOGRANULOMA VENEREUM
Chancroid, formerly “soft chancre,” is a sexually transmitted disease characterized by painful ulcers, and painful inguinal lymphadenopathy (buboes). The causative organism, Haemophilus ducreyi, was found by Ducrey in 1889. It is a gram-negative coccoid-bacillary rod that is found at the bottom of the initial ulcer, from which it spreads through lymphatic channels to the inguinal nodes, causing necrosis. H. ducreyi enters the skin through an epithelial break, usually following sexual intercourse. With a mean incubation period of 5 to 7 days, the bacteria secrete a cytolethal toxin that inhibits cell proliferation and induces cell death, causing the characteristic ulcer formation.
The ulcer, very painful and often located around the sulcus of the glans, is characterized by a “soft chancre” with steep edges, irregular borders, undermined skin, and a ring of erythema. It begins as a small congested area that develops into a macule and later a pustule surrounded by a hyperemic zone. A dirty ﬂoor due to the presence of exudate and sloughing tissue, and a profuse, purulent discharge are typical. Inguinal buboes may rupture after becoming an abscess and heal with scarring. This can result in chronic lymphatic obstruction and late elephantiasis-like changes to the penile and scrotal skin. The diagnosis is made from the clinical appearance of the lesions, by polymerase chain reaction (PCR) directed against one of two genomic segments (ribosomal RNA gene or the GroEL gene), or by Gram stain showing H. ducreyi appearing like “schools of ﬁsh,” “railroad tracks,” or “ﬁngerprints.” Organism culture is unreliable and insensitive. Immunochromatography is a more rapid but less available test that uses monoclonal antibodies to the hemoglobin receptor on the bacteria. Treatment involves incision and drainage of buboes and curative antibiotics.
Lymphogranuloma venereum (LGV) is a sexually transmitted disease caused by invasive Chlamydia trachomatis. LGV may begin as a self-limited, painless genital ulcer that occurs at the contact site 3 to 12 days after inoculation. It usually heals rapidly, unless secondary infection occurs. The secondary stage occurs from 10 to 30 days later as the infection spreads to inguinal lymph nodes. Systemic signs of fever, decreased appetite, and malaise may occur as well. Buboes are typically painful at ﬁrst and are associated with necrosis and abscess formation with chronic infection. There can be varying degrees of lymphatic obstruction and chronic edema caused by ﬁbrosis as a result. The diagnosis is made by the appearance of the chronic ulcerative process in the inguinal area, and historically (before 1974) by a positive skin test (Frei test) following intra- dermal injection of Chlamydia antigen. Ulcer biopsy histology is not pathognomonic. Complement ﬁxation is more sensitive (80%) but it has cross-reactivity with other Chlamydia species. Other blood tests such as microimmunoﬂuorescence test for the L-type serovar of C. trachomatis and PCR are very sensitive and speciﬁc, but test availability is limited. Bacterial culture from aspirated material is deﬁnitive bu lacks sensitivity. Treatment with antibiotics is curative.