Final answer:
The first-line treatment for head lice involves over-the-counter pediculicides, which are topical treatments applied to the scalp to eliminate lice, while antibiotics and corticosteroids are not effective for killing lice.
Step-by-step explanation:
The first-line treatment for head lice is the use of over-the-counter pediculicides. These are topical treatments that are applied directly to the scalp and hair to eliminate lice. Examples of these treatments include permethrin and pyrethrins, which are insecticidal preparations specifically intended to target and kill lice. Oral antibiotics are not used for treating head lice, as they are ineffective against these parasites. Topical corticosteroids may be used to alleviate the itching associated with head lice infestation but do not kill the lice themselves. Intravenous antivirals are irrelevant in this context as head lice are not caused by viruses. It is important to follow the instructions on the pediculicide product for effective treatment and to re-treat as specified by the product guidelines or healthcare provider, in case of re-infestation or if live lice are still found after the initial treatment.