Agent: Chlamydia trachomatis, subtypes L1, L2, and L3.
Appearance: intracellular organisms.
Clinical: 3 stages:
Primary (genital): papule → pustule formation on the genitals, following 0.5 - 6-week incubation period.
Secondary (inguinal): painful inguinal lymphadenopathy (bubo), usually unilateral, with abscess formation and rupture in 1/3 of cases.
Tertiary: genital ulcers, fistulas, elephantiasis, and rectal strictures. Transmission: sexual (rare in the US: more often seen in Africa, Asia, and South America.
Histology: nonspecific; diagnosis depends upon culture and identification of the organism.
Treatment: antibiotics, as long as they are administered early in the course of disease.