Syphilis is a chronic, systemic sexually transmitted infection (STI) caused by the gram-negative spirochete bacteriumTreponema pallidum subspecies pallidum. Transmission occurs primarily through direct sexual contact with active infectious lesions, but also transplacentally (congenital syphilis), via blood transfusion, or through skin breaks contacting infectious lesions. Untreated, the disease progresses through four distinct clinical stages: primary (painless chancre at the site of entry), secondary (systemic dissemination — rash, condylomata lata, mucous patches), latent (asymptomatic; seroreactive with no clinical signs), and tertiary (gummatous, cardiovascular, or neurologic destruction). Because syphilis can mimic virtually any disease — presenting as rash, meningitis, dementia, aortic aneurysm, uveitis, hepatitis, and more — it earned the historic title “the great imitator” and continues to be the “great mimicker” in modern medicine. Syphilis disproportionately affects men who have sex with men (MSM) and people with HIV, and rates have risen sharply in the United States since the early 2000s. As an inpatient profee coder, syphilis appears in neurology, cardiology, psychiatry, and infectious disease admissions — neurosyphilis (A52.3) and cardiovascular syphilis (A52.0x) are the most clinically severe and code-impactful presentations you’ll encounter; always check the CSF and serology results in the chart when either is suspected.
New Latin, from Girolamo Fracastoro’s 1530 Latin poem Syphilis sive morbus Gallicus
Named after Syphilus, a fictional shepherd in the poem who was the first person to contract the disease — sent as divine punishment by the sun god Apollo for defiance
The full poem title translates as “Syphilis, or the French Disease” — reflecting the pan-European blame game of the early outbreak era
The word syphilis entered medical English in 1718 as Modern Latin, originally from the title of an epic Latin poem published in 1530 by the Veronese physician and poet Girolamo Fracastoro (c. 1476-1553). Fracastoro coined the name from his protagonist — a shepherd named Syphilus — believed to be derived from the figure Sipylus in Ovid’s Metamorphoses. Fracastoro first applied the term as a generic disease name in his landmark epidemiological treatise De Contagione et Contagiosis Morbis in 1546, making it one of only a handful of diseases named after a fictional literary character. Before Fracastoro’s coinage, the disease was known across Europe variously as the “French disease” (morbus Gallicus), the “Neapolitan disease,” the “Italian disease,” and in Britain as the “Great Pox.”
🔀 ALIASES / ALTERNATE TERMS
Lues / Lues venerea(classical Latin clinical term; still used in lab/chart shorthand — “lues” = plague)
The Great Imitator(clinical nickname reflecting its ability to mimic almost any disease)
The Great Pox(historical British term distinguishing it from smallpox)
Morbus Gallicus(Latin: “French disease” — the pre-Fracastoro European name)
VDRL (Venereal Disease Research Laboratory) — nontreponemal screening test; positive in active disease; used to monitor treatment response
RPR (Rapid Plasma Reagin) — nontreponemal screening test; similar to VDRL; used for initial screening
FTA-ABS (Fluorescent Treponemal Antibody Absorption) — treponemal confirmatory test; remains positive for life even after treatment
TP-PA (Treponema pallidum Particle Agglutination) — treponemal confirmatory test; used in reverse screening algorithm
Benzathine penicillin G (Bicillin L-A) — first-line treatment for all stages of syphilis; single IM injection for primary/secondary; three doses for late latent/tertiary
Jarisch-Herxheimer reaction — febrile reaction within hours of syphilis treatment; due to endotoxin release from dying spirochetes
HIV co-infection — dramatically accelerates syphilis progression; neurosyphilis more common; requires CSF evaluation
TORCH infections — group of congenital infections (Toxoplasma, Other [syphilis], Rubella, CMV, HSV)
CODING CORNER
🏥 ICD-10-CM CODES
Congenital Syphilis — Category A50
(Transmitted mother to fetus in utero or at delivery)
HIV-1 and HIV-2, single result (alternative HIV screen)
⚠️ Coding Note:A53.9 (syphilis, unspecified) is a last-resort code — the stage and type are almost always determinable from serology titers, treatment records, and provider documentation. For neurosyphilis, stage specificity matters enormously: A52.11 (tabes dorsalis), A52.17 (general paresis), and A52.3 (neurosyphilis, unspecified) are distinct codes — pull the neurologist’s consult note and CSF results before defaulting to unspecified. Congenital syphilis (A50) is a high-priority public health code and a frequent focus of maternal/newborn quality audits — document whether it is early vs. late AND symptomatic vs. latent. For inpatient profee, the CSF-VDRL performed via lumbar puncture (62270) is your key procedure for neurosyphilis claims — confirm the ordering provider interpreted the results AND documented their clinical impression based on the CSF findings. When syphilis is co-diagnosed with HIV, code both (sequence based on reason for admission); HIV + neurosyphilis is a clinically significant combination that affects care intensity and DRG weight. Jarisch-Herxheimer reaction post-treatment is not separately coded in ICD-10-CM — document it narratively for clinical completeness but it does not have its own billable code at this time.
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