Head Lice – Symptoms and Causes

Understanding Head Lice

Head lice are small insects that live on the human scalp and feed on blood. They’re most common in children and spread easily through direct hair-to-hair contact.

These tiny pests don’t jump or fly but crawl from one person’s hair to another’s when heads touch.

Female lice lay eggs (called nits) that stick firmly to hair shafts near the scalp. These eggs hatch in about 8-9 days, continuing the life cycle.

Having head lice doesn’t mean someone is dirty or unclean. These insects can affect anyone regardless of personal hygiene or living conditions. It’s also important to know that head lice don’t spread diseases.

Several treatment options exist for head lice infestations:

• Over-the-Counter Medications: Specially formulated shampoos and lotions.
• Prescription Treatments: Stronger options available from healthcare providers.
• Manual Removal: Special combs to remove lice and nits.

For best results, follow treatment instructions carefully. Complete all steps to eliminate both live lice and their eggs.

Home remedies like olive oil, mayonnaise, or tea tree oil are popular but have limited scientific evidence supporting their effectiveness.

Symptoms

Head lice typically cause several noticeable signs. Itching on the scalp, neck, and ears is the most common symptom, resulting from an allergic reaction to the bites.

For first-time infestations, this itching might not begin until 4-6 weeks after exposure.

The lice themselves may be visible on the scalp, though they can be difficult to spot. These tiny parasites avoid light and move quickly, making detection challenging.

Nits (lice eggs) attach firmly to hair shafts and are most easily seen near the ears and neck hairline. These eggs appear as:

• Tiny specks stuck to hair
• Lighter colored when empty
• Located at varying distances from the scalp

Persistent scratching due to the intense itching can lead to small, red bumps on the scalp, neck, and shoulders. These sores may occasionally become infected with bacteria if scratching continues.

Many people confuse dandruff or hair product residue with nits, but unlike these substances, nits firmly attach to the hair and cannot be easily brushed away.

When to see a doctor

Visit a healthcare provider before starting any head lice treatment for yourself or your child. A medical professional can confirm if head lice are actually present.

Research shows many children receive unnecessary treatments when they don’t have lice.

Several things are commonly mistaken for lice eggs (nits), including:

• Dandruff
• Hair product buildup
• Dead hair tissue beads
• Scabs or dirt
• Other small insects in the hair

Getting a proper diagnosis helps avoid using medications or remedies when they aren’t needed. This is especially important since many lice treatments contain chemicals that shouldn’t be used unnecessarily.

What Causes Head Lice

How Head Lice Develop

Head lice are small tan or gray insects about the size of a strawberry seed. They feed on blood from the human scalp.

Female lice use a sticky substance to attach eggs firmly to hair shafts, placing them less than 1/4 inch from the scalp.

The life cycle of head lice has three main stages:

1. Eggs (Nits): These hatch after 6-9 days.
2. Nymphs: Immature lice that develop for 9-12 days before becoming adults.
3. Adults: Fully grown lice that can live 3-4 weeks, with females laying 6-10 eggs daily.

How Head Lice Spread

Head lice move by crawling—they cannot jump or fly. They most often spread through direct head-to-head contact between people. This commonly happens:

• Within families
• Among children at school
• During playtime activities

While less common, lice can also spread through shared personal items such as:

• Hats and scarves
• Brushes and combs
• Hair accessories
• Headphones
• Pillows and towels

Lice may also spread when clothing items are stored together. For example, hats hanging on the same hook or scarves kept in the same school locker can transfer lice from one person to another.

It’s important to note that household pets like dogs and cats do not play any role in spreading head lice. These parasites are specialized to live on human hosts only.

Risk Factors

Head lice spread mainly through direct head-to-head contact. Children in preschool and elementary school have the highest risk of getting head lice in the United States. This is because young children often:

• Play closely together
• Share personal items
• Have frequent head-to-head contact during activities
• Attend school or daycare where lice can spread easily

The risk increases in settings where many children interact closely with each other.

Complications

Frequent scratching of an itchy scalp caused by head lice can break the skin. These small cuts on the scalp may become infected. When children scratch intensely, they risk damaging their skin and creating entry points for bacteria.

Prevention

Stopping head lice from spreading among children in schools and daycare centers can be challenging.

This is because kids often have close contact with each other. While indirect spread through personal items is less common, there are still steps children can take to reduce their risk.

Children should:

• Hang their clothing on separate hooks from other children’s items
• Not share personal grooming items like combs and brushes
• Avoid sharing hats and scarves
• Stay away from beds, couches or pillows that someone with head lice has used

Sharing protective headgear for activities like sports or biking is typically fine when necessary. The most important prevention measures focus on avoiding direct head-to-head contact and not sharing personal hair care items.