Pubic Lice and Scabies — STIs You Can Actually See

Most STIs require lab testing to detect. Pubic lice and scabies are different — they're parasites, often visible (or detectable from their effects), and treatable in days with topical medications.

They're not dangerous, but they're uncomfortable, contagious, and require partner treatment.

The short answer

Pubic lice ("crabs")

What they look like

• Adult lice are 1-2mm, grayish-white or yellow-brown
• Visible to the naked eye if you look closely
• Nits (eggs) are tiny white/yellow specks attached to hair shafts at the base
• Move slowly compared to head lice

Symptoms

• Itching in pubic area, sometimes intense
• Itching worse at night
• Small specks (lice) visible on skin or hair
• Small dark spots (lice feces) on underwear
• Bluish marks on skin where lice have fed (rare)
• Mild fever, irritability (in heavy infestations — uncommon)

How they spread

• Sexual contact — primary route
• Close body contact that allows lice to crawl from one person to another
• Sharing bedding, towels, clothing — possible but less common (lice die within 24-48 hours away from a host)

Diagnosis

• Visual inspection
• Sometimes nits visible at base of hair shafts
• Magnifying lens helps
• Sometimes microscope confirmation

Treatment

OTC options:

• Permethrin 1% lotion or cream rinse (Nix, Rid)
  • Apply to dry pubic area
  • Leave on for 10 minutes
  • Rinse off
  • Repeat in 7-10 days to catch newly-hatched lice
• Pyrethrin shampoo — similar use

Prescription options:

• Ivermectin oral (for resistant cases)
• Malathion lotion (rarely used)
• Lindane (rarely used due to toxicity)

After treatment

• Itching may persist for a few days
• Wash all clothing, bedding, towels used in past 2 days in hot water (130°F+)
• Or seal items in plastic bag for 2 weeks
• Don't share bedding or towels with anyone until treated and clear
• Treat all sexual partners from past 30 days
• Repeat treatment in 7-10 days to catch newly hatched lice

Eyelashes affected?

• Don't use permethrin near eyes
• Petroleum jelly applied to lash bases 2x/day for 8 days can suffocate lice
• Or see ophthalmologist for safer prescription options

Resistance

• Some pubic lice are resistant to permethrin
• If treatment doesn't work in 1-2 weeks, switch to alternative
• Ivermectin oral is option for resistant cases

Scabies

What it is

Tiny mites (Sarcoptes scabiei) that burrow into the upper layer of skin and lay eggs. The body's immune reaction to the mites and their products causes intense itching.

Symptoms

• Intense itching, especially at night
• Rash — small red bumps or blisters
• Burrow lines — short, wavy lines on skin (especially between fingers, wrists, elbows, waistline, genitals)
• Nodules — sometimes persistent firm bumps after treatment
• Crusted scabies — severe form with thick crusty skin, in immunocompromised people

Where it appears

• Web of fingers (between digits)
• Wrists, elbows
• Underarms
• Waistline
• Genitals
• Buttocks
• Breasts (in women)
• Generally spares head/face/scalp (except in young children)

How it spreads

• Close skin-to-skin contact — sexual, family, household
• Sharing bedding, clothing, towels — more important than for pubic lice (scabies mites live longer off-host)
• Casual contact unlikely — usually requires 10-15 minutes of skin contact
• Highly contagious in close-living situations (households, nursing homes, dorms)

Diagnosis

• Clinical: rash + intense itching especially at night + characteristic distribution
• Microscopy: scraping of burrow examined under microscope (gold standard)
• Sometimes dermoscopy

Treatment

First-line:

• Permethrin 5% cream (prescription)
  • Apply to entire body from neck down
  • Leave on for 8-14 hours (often overnight)
  • Wash off
  • Repeat in 1 week

Alternative:

• Oral ivermectin — 200 mcg/kg single dose, repeat in 1-2 weeks
  • Good for crusted scabies or treatment failure
  • Easier than topical for some patients

For crusted scabies:

• Combination of topical permethrin AND oral ivermectin
• Multiple treatment cycles
• Specialist care

Itching after treatment

• Normal to itch for 2-4 weeks after successful treatment
• This is the immune response to dead mites, not active infestation
• Topical steroid cream + antihistamine for symptom relief
• Don't re-treat unless new evidence of active infection

Household and partner treatment

• Treat all household members and sexual partners simultaneously
• Even those without symptoms
• Mites can live 2-3 days off-host
• Wash all bedding, towels, clothing in hot water + high-heat dryer
• Or seal in plastic bag for 1 week (mites die)
• Vacuum upholstery thoroughly

When to see a doctor

• Suspected pubic lice or scabies
• OTC treatment hasn't cleared lice in 2 weeks
• Intense itching that's affecting sleep
• Visible skin infection (redness, pus, fever)
• Recurrent infestations
• Crusted/Norwegian scabies (severe form)
• Pregnancy + suspected infestation

Common confusion with other conditions

Eczema

• Can look similar (red, itchy rash)
• Eczema usually doesn't have burrow lines
• Eczema patterns are different

Allergic reaction

• New soap, lotion, fabric softener
• Usually clear with avoidance + topical steroid

Dermatitis

• Various causes; usually doesn't itch as intensely at night

Other STIs

• Different distribution
• Different appearance
• Need different treatment

Hygiene during and after treatment

What needs washing

• All clothing worn in past 2-3 days
• All bedding (sheets, pillowcases, blankets)
• All towels used recently
• Anything else in close skin contact

How to wash

• Hot water (130°F+ / 54°C+)
• High heat dryer cycle
• Or dry-clean
• Or seal in plastic bag for 2 weeks (lice) / 1 week (scabies)

Don't share

• Bedding
• Clothing
• Towels
• Until everyone treated and clear

Partner notification

• Sexual partners from past 30 days for pubic lice
• Sexual partners + close household contacts for scabies (within past month or so)
• Both should be treated simultaneously
• Even asymptomatic — they can be in incubation

Special situations

Pregnancy

• Permethrin 1% (pubic lice) — safe in pregnancy
• Permethrin 5% (scabies) — safe in pregnancy
• Avoid lindane and ivermectin in pregnancy
• Treatment is important to prevent neonatal exposure

Children

• Pubic lice in children is uncommon; consider sexual abuse evaluation if seen in pre-pubescent child
• Scabies is common in children — typical treatments work; use permethrin per pediatrician

Immunocompromised

• Crusted scabies risk
• Requires aggressive treatment
• Hospitalization sometimes needed
• Combined oral + topical treatment

Treatment failure

• Re-evaluate diagnosis
• Consider drug resistance
• Switch agents
• Specialist referral

Common myths

"Crabs and scabies are dirty diseases — only unhygienic people get them." Not true. Both affect people regardless of hygiene. They spread through close contact, not from being dirty.

"You can get them from a toilet seat." Pubic lice essentially never spread this way. Scabies very rarely.

"Shaving cures crabs." It can reduce population but doesn't eliminate them. Treatment is still needed.

"Itching after treatment means it didn't work." For scabies especially: itching can continue for 2-4 weeks after successful treatment due to immune response.

Long-term consequences

• Treated cases have no long-term consequences
• Skin infection from scratching is the main complication
• Pubic lice don't transmit other diseases
• Scabies doesn't transmit other diseases either (unlike body lice, which can)

Bottom line

Pubic lice ("crabs"):

• Visible insects in pubic hair
• Treat with OTC permethrin 1% or pyrethrin
• Treat partners; wash all bedding/clothing
• Repeat treatment in 7-10 days

Scabies:

• Microscopic mites causing intense itching + burrow lines
• Treat with prescription permethrin 5% (or oral ivermectin)
• Treat all household + partners simultaneously
• Itching continues 2-4 weeks after successful treatment — normal

Neither is dangerous, both are very treatable, and discreet help is widely available.

For more on related conditions, see genital itching causes, BV vs yeast vs STI, and STI testing window periods.