Visitors to Hawaii often inquire about “sand fleas,” a term that can cause confusion. While true sand fleas are crustaceans present in Hawaii, they do not bite humans. The biting insects commonly referred to as “sand fleas” are actually biting midges, also known as “no-see-ums” due to their minuscule size.
Understanding Sand Fleas in Hawaii
In Hawaii, the term “sand fleas” often refers to biting midges, tiny flying insects from the family Ceratopogonidae. True sand fleas are small crustaceans that do not bite people. These midges, measuring less than 1/8 inch (1-3 millimeters), are difficult to see, earning them the nickname “no-see-ums.”
Only female midges bite, needing blood to produce eggs. Their bites, which can feel more intense than a mosquito bite, appear as small, red, itchy bumps or welts, often in clusters. Reactions can last from several days to two weeks, depending on individual sensitivity.
Common Habitats and Active Times
Biting midges thrive in moist and humid environments, making many coastal and inland areas of Hawaii suitable habitats. They are found near coastal salt marshes, mud-coated flatlands, freshwater regions, and areas with damp soil or decaying organic matter. Breeding sites include the edges of springs, streams, ponds, and even damp tree crevices or areas with accumulated decaying leaves.
Midges are most active during periods of low light and calm air, typically at dawn and dusk. Their activity can extend throughout the night, especially in warm, humid conditions. While less common during bright daylight hours, they may still be present on overcast days or in areas with little wind. In Hawaii’s subtropical climate, biting midges can be active year-round, though their populations may peak during the warmer months, generally from March through November.
Preventing Encounters
To minimize bites, several preventive measures can be effective. Applying insect repellents containing active ingredients such as DEET or picaridin to exposed skin and clothing provides a protective barrier. Oil of lemon eucalyptus is another plant-based option recommended for repelling biting insects. Choosing repellents with at least 20% DEET can offer longer-lasting protection.
Wearing protective clothing, such as long-sleeved shirts and long pants, especially during peak activity times like dawn and dusk, can significantly reduce skin exposure. Light-colored clothing may also be less attractive to midges. When indoors, using air conditioning or fans can help, as midges are not strong flyers and struggle against air movement. Eliminating standing water around homes and avoiding known breeding grounds can further reduce their presence.
Relieving Bite Symptoms
If bites occur, several methods can help alleviate the discomfort. Wash the affected area with mild soap and water to clean the skin. Applying a cold compress or an ice pack wrapped in a cloth to the bites can help reduce swelling and numb the itching sensation. Over-the-counter topical treatments such as calamine lotion or hydrocortisone cream can provide relief by soothing skin irritation and reducing inflammation.
Oral antihistamines, available without a prescription, can also help manage the itching and any mild allergic reactions. Some individuals find relief from home remedies like applying a paste made from baking soda and water or using aloe vera gel. It is important to avoid scratching the bites, as this can break the skin and increase the risk of secondary infection. If bite symptoms worsen, show signs of infection such as increased redness, pain, pus, or fever, or if a severe allergic reaction like difficulty breathing or swelling of the face or throat occurs, prompt medical attention is advisable.