Topical and Oral Anti-Parasitics

Parasitic skin diseases include lice and scabies

What Topical and Oral Medications Are Used to Treat Parasites? 

Common parasitic infections of the skin include head lice (Pediculus humanus capitis), body lice (Pediculosis corporis), pubic lice (Pediculosis pubis), and scabies (Sacroptes scabiei).

Microscopic Image of Body Lice

A less common parasite that infects the skin is the hookworm, which can cause cutaneous larva migrans. Upon diagnosis of a parasitic skin infection, patients are usually given a topical anti-parasitic medication as the first line of treatment. In cases of severe, resistant, or recurrent infections, oral anti-parasitic medications may be prescribed. See Table 1 for a list of topical and oral anti-parasitic medications.

Table 1. Medications for Parasitic Skin Infections


Topical Medications

Oral Medications

Lice (pediculosis)

Permethrin cream/lotion (Acticin, Elimite)

Oral ivermectin (Stromectol)

Malathion (Ovide)


Benzyl alcohol (Ulesfia)

Trimethoprim-sulfamethoxazole (Bactrim, Sulfatrim Pediatric)

Spinosad (Natroba)


Topical ivermectin (Sklice, Soolantra)








(Sarcoptes scabiei)

Permethrin cream/lotion (Acticin, Elimite)

Oral ivermectin (Stromectol)



Crotamiton (Eurax)





Cutaneous larva migrans (caused by hookworms)


Oral ivermectin (Stromectol)


Albendazole (Albenza)

*Brand names in parenthesis


How Do Topical and Oral Anti-Parasitic Medications Work?[1]

  • Permethrin – inhibits important sodium channels on parasite cell membranes, leading to parasite paralysis and death[2]
  • Malathion – kills lice by inhibiting an enzyme in them called cholinesterase[2]
  • Benzyl alcohol – kills lice by suffocation[2]
  • Spinosad – kills lice by causing central nervous system overexcitation[3]
  • Lindane – causes seizures and death of parasites
  • Ivermectin – leads to paralysis and death of parasites
  • Crotamiton – unknown mechanisms of action against Sarcoptes scabiei
  • Albendazole – leads to the death of parasites by degrading parasites’ intestines and depleting their energy


What Conditions Do Anti-Parasitic Medications Treat? 

Table 2. FDA-Approved Uses of Anti-Parasitic Medications

Anti-Parasitic Medication

Skin Conditions

Other Conditions


Head lice, scabies



Head lice


Benzyl Alcohol[6]

Head lice

Mouth pain (cold sores, gum pain)



Head lice


Topical ivermectin[8]

Head lice, rosacea


Oral ivermectin[9]


Strongyloidiasis of the intestines


Head lice, scabies, pubic lice (not intended as first line treatment)




Urinary tract infections, otitis media, chronic bronchitis, infectious diarrhea, pneumonia


Scabies, itch




Echinococcus granulosus, neurocysticercosis 


How Are Anti-Parasitic Medications Given?

Topical anti-parasitic medications are typically given as a single application, although repeat applications are commonly required to eradicate the infection. Oral anti-parasitic medications are most commonly given once or twice per day for at least seven days. However, some infections may only require a single dose while others may require extended treatment beyond seven days.[14]

  • Permethrin – For head lice, the permethrin solution should be applied to the entire scalp and dry hair. After soaking for approximately 10 minutes, the permethrin can be rinsed out with water and the treatment should be repeated on day nine.[15]  For treatment of scabies, permethrin cream should be applied to the entire body, including the soles of the feet and under fingernails and toenails to kill the live scabies mites. The cream can be washed off after approximately 10 hours. Most physicians will require a second application one to two weeks later in order to kill any scabies eggs that might have hatched in the time since the first application.[16]
  • Ivermectin – For both lice and scabies, oral ivermectin is often given as a single dose with a second dose given approximately one week later.[16] 


What Are Common Side Effects and Risks of Anti-Parasitic Medications?

Table 3. Most Common Side Effects of Anti-Parasitic Medications[1]


Skin burning, stinging, tingling, rash


Skin stinging and irritation

Benzyl alcohol

Skin itch, redness


Skin redness and irritation

Topical ivermectin

Localized irritation or burning

Oral ivermectin

Itch, fever, rash, lymph node tenderness, joint pain, irregular heart rate


Ataxia, dizziness, neurotoxicity, seizure, rash, aplastic anemia 

* This Website is for general skin beauty, wellness, and health information only. This Website is not to be used as a substitute for medical advice, diagnosis or treatment of any health condition or problem. The information provided on this Website should never be used to disregard, delay, or refuse treatment or advice from a physician or a qualified health provider.


  1. de Silva N, Guyatt H, Bundy D. Anthelmintics. A comparative review of their clinical pharmacology. Drugs.1997;53(5):769-788; PMID: 9129865.
  2. Frankowski BL, Bocchini JA, Jr. Head lice. Pediatrics.2010;126(2):392-403; PMID: 20660553.
  3. Stough D, Shellabarger S, Quiring J, et al. Efficacy and safety of spinosad and permethrin creme rinses for pediculosis capitis (head lice). Pediatrics.2009;124(3):e389-395; PMID: 19706558.
  4. FDA. PERMETHRIN CREAM 5%. 1998.
  5. FDA. Malathion Lotion USP 0.5% 2009.
  6. FDA. Ulesfia (benzyl alcohol) lotion. 2009.
  7. FDA. Natroba (spinosad) topical suspension, 0.9%. 2011.
  8. FDA. SKLICE (Ivermectin) Lotion, 0.5%.
  9. FDA. Stromectol (Ivermectin). 2009.
  10. FDA. Lindane Lotion USP, 1%. 2003.
  11. FDA. BACTRIM(TM) sulfamexthoxazole and trimethoprim DS tablets and tablets USP. 2013.
  12. FDA. Eurax (crotamiton USP). 2003.
  13. FDA. Albenza(R) (albendazole) Tablets. 2009.
  14. Hochedez P, Caumes E. Common skin infections in travelers. J Travel Med.2008;15(4):252-262; PMID: 18666926.
  15. Meinking TL, Clineschmidt CM, Chen C, et al. An observer-blinded study of 1% permethrin creme rinse with and without adjunctive combing in patients with head lice. J Pediatr.2002;141(5):665-670; PMID: 12410195.
  16. Currie BJ, McCarthy JS. Permethrin and ivermectin for scabies. N Engl J Med.2010;362(8):717-725; PMID: 20181973.