Bugs, bugs, bugs, everywhere there are bugs. Lice, scabies, ticks, and mosquitos all infect humans in unique ways.
Lice or Pediculosis Capitis is responsible for millions of infections yearly in the United States. Lice are approximately 3 mm in length, wingless, unable to fly or jump, spread in times of close contact, and survive 24-48 hours away from humans. Nits are lice eggs less than 1 mm, white, hatching in 7-10 days, maturing to adults in about 1-2 weeks. Lice’s saliva prevents coagulation and results in itching.
A variety of treatment modalities exist for lice. Permethrin 1%, pyrethrin plus piperonyl butoxide, Malathion, Spinosad 0.9%, Ivermectin 0.5% lotion, and benzyl alcohol 5% lotion are examples. All but Malathion is administered to dry damp hair for 10 minutes before rinsing and repeated in 7-10 days. Malathion is administered to dry hair and left in place for 8-12 hours before rinsing. Ivermectin is only applied once. Permethrin 1% is used for 2 months or older. Malathion is used for 6 years and older. All chemicals possess the potential of causing itching, redness, and swelling. Additional cautions include malathion as flammable chemical.
In preventing spread and maintaining safety, specific considerations are described. For example, bedding, clothing, hats, are sterilized by washing in hot water, freezing, or smothering in a sealed plastic bag. Caution around close contact is essential for reducing transmission.
In fact, close living areas potentiate easy spread of body lice or pediculosis corporis. Body lice prefer warm areas such as waist band areas and cause itching and redness. Treatment includes permethrin 5% application on body for 8-12 hours before washing off as first line therapy. However, oral ivermectin may be used as an alternative. The itching is treated with corticosteroids.
Pediculosis Pubis are sexually transmitted and most common among young adults. Opthalmic petrolatum is recommended to kill the lice following two to four times a day application.
Scabies similar to lice is transmitted by close contact. They are typically located in waist band and between digets where they burrow and result in itching. These symptoms may take up to 4-6 weeks to manifest and unfortanantely, transmission continues to occur. The amount of mites is 10-15 and often used to confirm diagnosis along with the rash appearance. Treatment includes permethrin 5% cream applied head to toe, leaving on for 8-12 hours, and washing off in the morning with a repeat application if necessary in 7 days. Bedding and clothing is washed with hot water and/or stored in sealed plastic bag for a week. Symptoms are treated with oral antihistamines, moisturizers, and low dose corticosteroids.
These therapies are also used to treat insect bites. The insects are often mosquitos, ticks, flies, and fleas. Prevention strategies include insect repellants such as DEET 20-30% approved for older than 2 months of age, bed nets, clothing, and avoiding wooded, wet areas. When prevention fails, then washing the affected area with warm soapy water, applying a cold pack, and using anti-inflammatory products are recommended for optimal symptomatic reduction.
In conclusion, integumentary alterations with bugs require knowledge and usage of preventative and treatment strategies. Many products are available for these applications. Consult with prescriber or pharmacist for the best product and strategy to reduce complications.
Pharm D, BCPS, BCACP, CDE, MSMTM