Alopecia syphilitica is non-scarring hair loss that can occur during secondary syphilis. The classic pattern is “moth-eaten” hair loss—small, irregular patches of thinning that can be easy to confuse with other conditions.
Medical note: This article is for general education and does not provide personal medical advice. If syphilis is a possibility, seek prompt testing and clinician guidance. For the full roadmap, start here: Hair Loss (Complete Guide).
Quick navigation
- What it is (plain English)
- What it usually looks like
- Why it happens (simple mechanism)
- Conditions that can look similar
- How it’s diagnosed
- Treatment (high-level)
- What to do (safe next steps)
- When to see a doctor
- FAQ
- References
What is alopecia syphilitica?
Alopecia syphilitica is hair loss associated with syphilis, most often during the secondary stage. It is typically non-scarring, meaning follicles are not destroyed and regrowth is common after appropriate treatment.
On our site, this belongs under: Non-Scarring Alopecia (Hub) and the big-picture map: Types of Hair Loss.
What it usually looks like
The classic clue is the pattern:
- “Moth-eaten” alopecia: small, irregular patches of thinning (often not perfectly round)
- Diffuse thinning: less specific; can resemble telogen effluvium
- Often minimal scale and no scarring
Why it happens (simple mechanism)
The exact mechanism is not fully settled, but syphilitic alopecia is thought to reflect an inflammatory/infectious process affecting the hair cycle. The key practical point is that follicles are usually preserved (non-scarring), so treating the underlying infection often leads to regrowth.
Conditions that can look similar (important)
Alopecia syphilitica is a well-known “mimicker.” Common look-alikes include:
- Alopecia areata: smooth round/oval patches; often sharply demarcated.
Read: Alopecia Areata. - Tinea capitis: consider if there is scale, black dots, broken hairs, itch, or a child is affected.
Read: Tinea Capitis. - Trichotillomania: irregular patches with hairs of different lengths; behavioral component.
Read: Trichotillomania. - Telogen effluvium: diffuse shedding with a trigger/timeline.
Read: Telogen Effluvium.
How it’s diagnosed
Diagnosis requires blood testing for syphilis (typically a combination of screening + confirmatory tests). Because syphilis can involve multiple organ systems and can be contagious, confirmation matters.
Use our framework pages:
Treatment (high-level)
Syphilis is treated with antibiotics. Treatment choice depends on disease stage and clinical context, so it should be directed by a clinician using current guidelines. After appropriate treatment, hair regrowth is commonly expected over weeks to a few months.
What to do (safe next steps)
- Get tested promptly: don’t assume it’s “just alopecia areata” when the pattern is irregular or “moth-eaten.”
- Ask about a full exam: secondary syphilis can have skin/mucosal findings and systemic symptoms.
- Avoid self-treating with random hair meds first: the priority is confirming/ruling out an infection.
- Be gentle with hair care: avoid harsh traction/chemicals until the diagnosis is clarified.
When to see a doctor (red flags)
- Rash (especially palms/soles), mouth sores, or generalized symptoms (fever, swollen nodes)
- Eye or neurologic symptoms (urgent evaluation)
- Pregnancy (urgent testing/treatment to protect the baby)
- Rapid progression or uncertainty about diagnosis
Read: When to See a Doctor.
FAQ
Is alopecia syphilitica permanent?
It is usually non-scarring, so regrowth is common after appropriate treatment—though timing varies.
Can hair loss be the only sign?
Yes. While many people have other symptoms of secondary syphilis, some reports describe hair loss as a prominent (or even the main) presenting sign.
How fast does hair grow back?
Many reports describe visible regrowth within weeks and more substantial regrowth by around 3 months after treatment, though individual timelines vary.
References (trusted medical sources)
- CDC: About Syphilis (includes patchy hair loss as a secondary symptom)
- CDC: Syphilis — STI Treatment Guidelines
- DermNet: Syphilis (secondary syphilis can include patchy alopecia)
- WHO: Syphilis fact sheet
- NEJM Image in Clinical Medicine: Syphilitic Alopecia
- PMC: “Moth-eaten alopecia” as a sign of secondary syphilis
- PMC Review: Alopecia syphilitica — diagnosis to treatment (regrowth expectations)
- Frontiers in Medicine: Clinical + trichoscopic features; regrowth after therapy
Last updated: February 02, 2026.
