Genital bumps or lumps are most often caused by one of three STIs — HPV (genital warts), molluscum contagiosum, or genital herpes — but many harmless, non-STI conditions look nearly identical. Because these overlap so much by sight, only a test can tell you which one (if any) you have.
Human papillomavirus
Molluscum contagiosum virus
Herpes simplex virus
| Item | Value |
|---|---|
| HPV & genital warts | managed — Human papillomavirus |
| Molluscum contagiosum | curable — Molluscum contagiosum virus |
| Genital herpes | managed — Herpes simplex virus |
The short list of likely causes
When a new bump shows up below the belt, the realistic suspects fall into two buckets. The first is sexually transmitted: HPV (which can produce genital warts), molluscum contagiosum, and genital herpes. The second is a group of completely benign, extremely common skin findings that aren't infections at all — Fordyce spots, pearly penile papules, skin tags, cysts, and ingrown hairs CDC.
These conditions overlap too much to tell apart reliably by eye, and several of them are frequently silent or produce only a tiny, easy-to-miss lesion. A clinical exam plus targeted testing settles it. People go wrong self-diagnosing from a phone photo.
Which STIs cause genital bumps or lumps
HPV and genital warts
HPV is the most common STI, and certain types cause genital warts. A wart usually shows up as a small bump or a cluster of bumps in the genital area — they can be flat, raised, or take on a cauliflower-like texture, and they're typically painless. Many people with HPV never develop warts at all: most HPV infections are asymptomatic and cause no visible disease, and the high-risk types tied to cancer are essentially never something you'd feel or see CDC Pink Book.
Timing is unpredictable. The CDC doesn't give a fixed incubation window for warts. They can appear months or even years after you acquire HPV, so the moment of infection often can't be pinned down. If you're wondering whether warts hurt, itch, or bleed, we cover the full symptom picture in do genital warts hurt? itching, bleeding & feel.
Molluscum contagiosum
Molluscum is a benign, usually mild skin infection caused by a poxvirus. In adults it's often spread through sexual contact. The tell-tale bump is small, firm, and pearly — white, pink, or skin-colored, roughly the size of a pinhead up to a pencil-eraser, with a distinctive small dip or dimple in the center CDC. They can crop up almost anywhere on the body (rarely the palms or soles) and are sometimes itchy or sore.
That central dimple is the single most useful clue separating molluscum from a wart, though it's not foolproof. For the full rundown of how these look and behave, see molluscum contagiosum bumps.
Genital herpes
Genital herpes is caused by two related viruses, HSV-1 and HSV-2. Most people have no symptoms or only very mild ones — most don't know they're infected, and the majority of HSV-2 infections are never diagnosed CDC. When symptoms do appear, herpes behaves differently from warts or molluscum: a first outbreak typically starts as blisters that break open into painful sores, which take a week or more to heal, often alongside flu-like symptoms such as fever, body aches, and swollen glands.
The sores show up on or around the genitals, rectum, or mouth. Later outbreaks tend to be shorter and less severe, and many people get a warning prodrome — tingling, itching, or burning — before a sore appears. What sets herpes apart is the pain and that blister-to-ulcer evolution; warts and molluscum are usually painless and stay solid.
When it's not an STI
A lot of genital bumps are normal anatomy or harmless skin findings that have nothing to do with sex. These are worth knowing so you don't panic over something benign:
- Pearly penile papules — small, uniform, dome-shaped bumps arranged in neat rows around the rim of the glans; a normal anatomical variant, not an infection.
- Fordyce spots — tiny pale or yellowish bumps that are simply visible oil glands, common on the shaft, scrotum, or vulva.
- Skin tags — soft, flesh-colored flaps of skin that can appear in skin folds; entirely harmless.
- Cysts — fluid- or material-filled lumps under the skin that feel like a movable nodule.
- Ingrown hairs — a red, sometimes tender bump where a shaved or waxed hair curls back into the skin; often resolves on its own.
All of these are common and harmless, and none require treatment unless they bother you. A pearly papule and a small wart, or a cyst and a molluscum bump, can look strikingly similar to an untrained eye.
How to tell them apart
Clinicians triage genital bumps by a handful of features: texture, whether they cluster, location, and whether there's pain. Use these as a guide, not a verdict:
- Texture and shape: Warts can be rough or cauliflower-like; molluscum is smooth, firm, and dimpled in the center; herpes starts as fluid-filled blisters that rupture into open sores.
- Pain: Herpes sores are usually painful and may burn or tingle first; warts and molluscum are typically painless.
- Clustering and spread: Warts often appear in groups and can multiply; molluscum can spread to nearby skin through scratching; herpes recurs in the same general spot.
- Healing: Herpes sores crust and heal over a week or more, then can return; warts and molluscum tend to persist without that blister-heal cycle.
Even so, the features overlap too much to be certain, and several of these conditions are frequently silent. A test settles which one it is.
Side-by-side comparison
| Feature | HPV / genital warts | Molluscum contagiosum | Genital herpes |
|---|---|---|---|
| Cause | Human papillomavirus | Poxvirus (molluscum contagiosum virus) | HSV-1 or HSV-2 |
| Typical look | Bump or cluster, sometimes cauliflower-like | Firm pearly bump with a central dimple | Blisters that break into open sores |
| Pain | Usually painless | Usually painless, sometimes itchy | Often painful; may have prodrome |
| Course | Can appear months to years after exposure | Usually mild, self-limited | Heals over a week or more, can recur |
| Other symptoms | Often none | Sometimes itchy or sore | First outbreak may bring fever, aches, swollen glands |
How it's tested
Testing depends on what's suspected. Herpes is confirmed when a lesion is present by swabbing the sore for type-specific virologic testing — a NAAT or culture works best when there's an active sore to sample CDC. There's no routine HPV test for men, adolescents, or women under thirty, so warts are usually diagnosed by a clinician's visual exam rather than a lab swab. Molluscum is also typically a clinical diagnosis based on the bump's appearance. For the full how-to, see get tested, and if you're counting days since a possible exposure, check when to test after exposure.
In practice, testing is straightforward: depending on what's being checked, you'll give a urine sample, do a self-collected swab, or get a quick exam. It's free or low-cost at health departments, Planned Parenthood, and Title X clinics, and results usually come back within a few days.
What to do next
Don't try to pop, scrape, or treat a genital bump on your own, since that can spread molluscum or worsen a herpes sore. Get it looked at and tested so you're treating the right thing. Treatment differs by cause: warts have several removal options, molluscum often clears without intervention, and herpes is managed with antiviral medication. If you're exploring options beyond standard prescriptions, we discuss alternative herpes treatments separately.
Red flags — when to get seen urgently
Most genital bumps aren't emergencies, but see a clinician promptly if you notice any of these:
- Painful sores or ulcers, especially with fever, body aches, or swollen glands suggesting a first herpes outbreak.
- A bump that's rapidly growing, bleeding, or changing in color or shape.
- Signs of infection around a lump — spreading redness, warmth, pus, or significant pain.
- Difficulty urinating, severe pain, or sores that won't heal.
- A new bump after recent sexual contact when you're unsure of your partner's status.