Sea Lice Are Not Spreadable from Person to Person
Sea lice bites (sea bathers eruption) are not contagious or spreadable from person to person, as they are not parasites that remain on the skin after leaving the water. 1
What Are Sea Lice?
Sea lice in humans refer to a condition called "sea bathers eruption," which is fundamentally different from the parasitic sea lice that affect fish in aquaculture settings:
- Human sea lice bites: These are actually stings from the microscopic larvae of jellyfish or sea anemones that get trapped between skin and clothing/hair while swimming. They are not true "lice" and do not remain on the body or spread between people.
- Fish sea lice: These are true parasitic copepods (Lepeophtheirus salmonis and Caligus species) that affect fish in marine environments 2, 3, 4. These parasites are host-specific to fish and cannot infest or survive on humans.
Key Differences from Head Lice
It's important to distinguish sea lice from head lice (Pediculus humanus capitis), which are actual parasites that can spread between humans:
- Head lice are transmitted primarily through direct head-to-head contact 5
- Head lice can rarely spread through shared personal items like combs, brushes, and hats 5
- Head lice require human blood to survive and cannot live more than 1-2 days away from the scalp 5
Treatment for Sea Lice Bites
If you've experienced sea lice bites, treatment focuses on managing symptoms rather than eliminating parasites:
- Topical corticosteroids to reduce inflammation
- Oral antihistamines to relieve itching
- Calamine lotion as a supportive measure 1
Prevention of Sea Lice Bites
To prevent sea lice bites when swimming in affected waters:
- Remove swimwear as soon as possible after leaving the water
- Shower promptly with fresh water
- Wash swimwear thoroughly before reuse
When to Seek Medical Attention
Medical attention should be sought if:
- Symptoms worsen or persist despite appropriate home treatment
- Secondary bacterial infection develops
- Systemic symptoms occur 1
Common Misconceptions
A common mistake is confusing sea lice bites with actual parasitic infestations. Using pediculicides (medications designed for head lice) is ineffective for sea lice bites since there are no parasites to eliminate 1.
The term "sea lice" is misleading as these are not lice at all, but rather a reaction to marine larvae stings. Unlike true parasitic conditions such as scabies or head lice that can spread through close contact 5, sea bathers eruption is not contagious and poses no risk of person-to-person transmission.