Most antiparasitic agents can be used by patients regardless of other medical conditions the patient may have. However, patients likely will be urged not to use these medications if they have a prior history of reaction to the drugs or if their skin is raw or inflamed.

Thiabendazole (used to treat “creeping eruption”) should not be used in patients with kidney or liver disorders, severe malnutrition or anemia. Lindane (used to treat scabies) should not be used in premature infants, pregnant women, patients with a history of seizures or patients with Norwegian scabies, a condition in which patients are infected with hundreds or thousands of scabies that cause severe skin manifestations. In addition, people with severely inflamed skin should not apply benzyl benzoate or crotamiton to the skin to treat scabies.  

Individuals with asthma should avoid taking ivermectin to treat scabies and head lice because the drug can worsen asthma. In addition, permethrin should not be applied to an inflamed scalp for the treatment of scabies or lice.