Treatment depends on the type of opportunistic infection, but usually involves different antibiotics.

Individuals at higher risk are often prescribed prophylactic medication to prevent an infection from occurring. A patient's risk level for developing an opportunistic infection is approximated using the patient's CD4 T-cell count and sometimes other markers of susceptibility. Common prophylaxis treatments include the following:

Systemic candidiasis occurs when Candida yeast enters the bloodstream and may spread (becoming disseminated candidiasis) to other organs, including the central nervous system, kidneys, liver, bones, muscles, joints, spleen, or eyes. Treatment typically consists of oral or intravenous antifungal medications. In candidal infections of the blood, intravenous fluconazole or an echinocandin such as caspofungin may be used. Amphotericin B is another option.

Antibiotics are commonly used to prevent secondary bacterial infection. There are no specific antiviral drugs in common use at this time for FVR, although one study has shown that ganciclovir, PMEDAP, and cidofovir hold promise for treatment. More recent research has indicated that systemic famciclovir is effective at treating this infection in cats without the side effects reported with other anti-viral agents. More severe cases may require supportive care such as intravenous fluid therapy, oxygen therapy, or even a feeding tube. Conjunctivitis and corneal ulcers are treated with topical antibiotics for secondary bacterial infection.

Lysine is commonly used as a treatment, however in a 2015 systematic review, where the authors investigated all clinical trials with cats as well as "in vitro" studies, concluded that lysine supplementation is not effective for the treatment or prevention of feline herpesvirus 1 infection.

When no pus is present, warm soaks for acute paronychia is reasonable, even though there is a lack of evidence to support its use. Antibiotics such as clindamycin or cephalexin are also often used, the first being more effective in areas where MRSA is common. If there are signs of an abscess (the presence of pus) drainage is recommended.

Chronic paronychia is treated by avoiding whatever is causing it, a topical antifungal, and a topical steroid. In those who do not improve following these measures oral antifungals and steroids may be used or the nail fold may be removed surgically.

Candidiasis is treated with antifungal medications; these include clotrimazole, nystatin, fluconazole, voriconazole, amphotericin B, and echinocandins. Intravenous fluconazole or an intravenous echinocandin such as caspofungin are commonly used to treat immunocompromised or critically ill individuals.

The 2016 revision of the clinical practice guideline for the management of candidiasis lists a large number of specific treatment regimens for "Candida" infections that involve different "Candida" species, forms of antifungal drug resistance, immune statuses, and infection localization and severity. Gastrointestinal candidiasis in immunocompetent individuals is treated with 100–200 mg fluconazole per day for 2–3 weeks.

Neonatal infection treatment is typically started before the diagnosis of the cause can be confirmed.

Neonatal infection can be prophylactically treated with antibiotics. Maternal treatment with antibiotics is primarily used to protect against group B streptococcus.

Women with a history of HSV, can be treated with antiviral drugs to prevent symptomatic lesions and viral shedding that could infect the infant at birth. The antiviral medications used include acyclovir, penciclovir, valacyclovir, and famciclovir. Only very small amounts of the drug can be detected in the fetus. There are no increases in drug-related abnormalities in the infant that could be attributed to acyclovir. Long-term effects of antiviral medications have not been evaluated for their effects after growth and development of the child occurs. Neutropenia can be a complication of acyclovir treatment of neonatal HSV infection, but is usually transient. Treatment with immunoglobulin therapy has not been proven to be effective.

Most treatments are topical or oral antifungal medications.

Topical agents include ciclopirox nail paint, amorolfine or efinaconazole. Some topical treatments need to be applied daily for prolonged periods (at least 1 year). Topical amorolfine is applied weekly. Topical ciclopirox results in a cure in 6% to 9% of cases; amorolfine might be more effective. Ciclopirox when used with terbinafine appears to be better than either agent alone.

Oral medications include terbinafine (76% effective), itraconazole (60% effective) and fluconazole (48% effective). They share characteristics that enhance their effectiveness: prompt penetration of the nail and nail bed, persistence in the nail for months after discontinuation of therapy. Ketoconazole by mouth is not recommended due to side effects. Oral terbinafine is better tolerated than itraconazole. For superficial white onychomycosis, systemic rather than topical antifungal therapy is advised.

Treatment consists of antibiotic therapy aimed at the typical bacterial pathogens in addition to supportive care for any complications which might result from the infection itself such as hypotension or respiratory failure. A typical regimen will include intravenous antibiotics such as from the penicillin-group which is active against "Staphylococcus aureus" and an aminoglycoside for activity against Gram-negative bacteria. For particularly invasive infections, antibiotics to cover anaerobic bacteria may be added (such as metronidazole). Treatment is typically for two weeks and often necessitates insertion of a central venous catheter or peripherally inserted central catheter.

Chemical (keratolytic) or surgical debridement of the affected nail appears to improve outcomes.

As of 2014 evidence for laser treatment is unclear as the evidence is of low quality and varies by type of laser.

As of 2013 tea tree oil has failed to demonstrate benefit in the treatment of onychomycosis. A 2012 review by the National Institutes of Health found some small and tentative studies on its use.

Although it is a self-limited illness, oral or intravenous antiviral treatments, particularly acyclovir, have been used in the management of immunocompromised or severely infected patients. Topical acyclovir has not been shown to be effective in management of herpetic whitlow. Famciclovir has been demonstrated to effectively treat and prevent recurrent episodes. Lancing or surgically debriding the lesion may make it worse by causing a superinfection or encephalitis.

Docosanol, a saturated fatty alcohol, is a safe and effective topical application that has been approved by the United States Food and Drug Administration for herpes labialis in adults with properly functioning immune systems. It is comparable in effectiveness to prescription topical antiviral agents. Due to its mechanism of action, there is little risk of drug resistance. The duration of symptoms can be shortened a bit if an antiviral, anesthetic, zinc oxide or zinc sulfate cream is applied soon after it starts.

Effective antiviral medications include acyclovir and penciclovir, which can speed healing by as much as 10%. Famciclovir or valacyclovir, taken in pill form, can be effective using a single day, high-dose application and is more cost effective and convenient than the traditional treatment of lower doses for 5–7 days.

Treatment for both pregnant and non-pregnant women is usually with metronidazole, by mouth once. Caution should be used in pregnancy, especially in the first trimester. Sexual partners, even if they have no symptoms, should also be treated.

For 95-97% of cases, infection is resolved after one dose of metronidazole. Studies suggest that 4-5% of trichomonas cases are resistant to metronidazole, which may account for some “repeat” cases. Without treatment, trichomoniasis can persist for months to years in women, and is thought to improve without treatment in men. Women living with HIV infection have better cure rates if treated for 7 days rather than with one dose.

Topical treatments are less effective than oral antibiotics due to Skene's gland and other genitourinary structures acting as a reservoir.

The medications prescribed for acute toxoplasmosis are the following:

- Pyrimethamine — an antimalarial medication

- Sulfadiazine — an antibiotic used in combination with pyrimethamine to treat toxoplasmosis

- Combination therapy is usually given with folic acid supplements to reduce incidence of thrombocytopaenia.

- Combination therapy is most useful in the setting of HIV.

- Clindamycin

- Spiramycin — an antibiotic used most often for pregnant women to prevent the infection of their children.

(other antibiotics, such as minocycline, have seen some use as a salvage therapy).

If infected during pregnancy, spiramycin is recommended in the first and early second trimesters while pyrimethamine/sulfadiazine and leucovorin is recommended in the late second and third trimesters.

During the 1950s there were outbreaks of omphalitis that then led to anti-bacterial treatment of the umbilical cord stump as the new standard of care. It was later determined that in developed countries keeping the cord dry is sufficient, (known as "dry cord care") as recommended by the American Academy of Pediatrics. The umbilical cord dries more quickly and separates more readily when exposed to air However, each hospital/birthing center has its own recommendations for care of the umbilical cord after delivery. Some recommend not using any medicinal washes on the cord. Other popular recommendations include triple dye, betadine, bacitracin, or silver sulfadiazine. With regards to the medicinal treatments, there is little data to support any one treatment (or lack thereof) over another. However one recent review of many studies supported the use of chlorhexidine treatment as a way to reduce risk of death by 23% and risk of omphalitis by anywhere between 27-56% in community settings in underdeveloped countries. This study also found that this treatment increased the time that it would take for the umbilical stump to separate or fall off by 1.7 days. Lastly this large review also supported the notion that in hospital settings no medicinal type of cord care treatment was better at reducing infections compared to dry cord care.

There is a vaccine for FHV-1 available (ATCvet code: , plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. Studies have shown a duration of immunity of this vaccine to be at least three years. The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.

Uncomplicated infections can be diagnosed and treated based on symptoms alone. Antibiotics taken by mouth such as trimethoprim/sulfamethoxazole (TMP/SMX), nitrofurantoin, or fosfomycin are typically first line. Cephalosporins, amoxicillin/clavulanic acid, or a fluoroquinolone may also be used. However, resistance to fluoroquinolones among the bacterial that cause urinary infections has been increasing. The FDA recommends against the use of fluoroquinolones when other options are available due to higher risks of serious side effects. These medications substantially shorten the time to recovery with all being equally effective. A three-day treatment with trimethoprim, TMP/SMX, or a fluoroquinolone is usually sufficient, whereas nitrofurantoin requires 5–7 days. Fosfomycin may be used as a single dose but has been associated with lower rates of efficacy.

With treatment, symptoms should improve within 36 hours. About 50% of people will recover without treatment within a few days or weeks. Fluoroquinolones are not recommended as a first treatment. The Infectious Diseases Society of America states this due to the concern of generating resistance to this class of medication. Amoxicillin-clavulanate appears less effective than other options. Despite this precaution, some resistance has developed to all of these medications related to their widespread use. Trimethoprim alone is deemed to be equivalent to TMP/SMX in some countries. For simple UTIs, children often respond to a three-day course of antibiotics. Women with recurrent simple UTIs may benefit from self-treatment upon occurrence of symptoms with medical follow-up only if the initial treatment fails.

In people with latent toxoplasmosis, the cysts are immune to these treatments, as the antibiotics do not reach the bradyzoites in sufficient concentration.

The medications prescribed for latent toxoplasmosis are:

- Atovaquone — an antibiotic that has been used to kill "Toxoplasma" cysts inside AIDS patients

- Clindamycin — an antibiotic that, in combination with atovaquone, seemed to optimally kill cysts in mice

The mainstay of treatment is antibiotics. Phenazopyridine is occasionally prescribed during the first few days in addition to antibiotics to help with the burning and urgency sometimes felt during a bladder infection. However, it is not routinely recommended due to safety concerns with its use, specifically an elevated risk of methemoglobinemia (higher than normal level of methemoglobin in the blood). Acetaminophen (paracetamol) may be used for fevers. There is no good evidence for the use of cranberry products for treating current infections.

Some vertically transmitted infections, such as toxoplasmosis and syphilis, can be effectively treated with antibiotics if the mother is diagnosed early in her pregnancy. Many viral vertically transmitted infections have no effective treatment, but some, notably rubella and varicella-zoster, can be prevented by vaccinating the mother prior to pregnancy.

If the mother has active herpes simplex (as may be suggested by a pap test), delivery by Caesarean section can prevent the newborn from contact, and consequent infection, with this virus.

IgG antibody may play crucial role in prevention of intrauterine infections and extensive research is going on for developing IgG-based therapies for treatment and vaccination.

Bumblefoot is so named because of the characteristic "bumbles" or lesions, as well as swelling of the foot pad, symptomatic of an infection. Topical antiseptics in addition to oral or injected antibiotics may be used to combat the infection, which if left untreated may be fatal.

A number of topical antivirals are effective for herpes labialis, including acyclovir, penciclovir, and docosanol.

The treatments used for plaque psoriasis can also be used for guttate psoriasis. Few studies have specifically focused on guttate psoriasis management, so there is currently no firm guidelines for managing guttate psoriasis differently from plaque psoriasis. Due to the role streptococcal infection plays in the development of guttate psoriasis, systemic antibiotics have been considered as a potential treatment option. Although systemic antibiotics may be considered to treat the initial infection at its source, there is no support for their use in the management of subsequent guttate psoriasis itself. The condition often usually clears up on its own within weeks to months, and only about one third of patients will develop chronic plaques.

Evidence from a randomized controlled trials for screening pregnant women who do not have symptoms for infection with trichomoniasis and treating women who test positive for the infection have not consistently shown a reduced risk of preterm birth. Further studies are needed to verify this result and determine the best method of screening. In the US, screening of pregnant women without any symptoms is only recommended in those with HIV as trichomonas infection is associated with increased risk of transmitting HIV to the fetus.

Several antiviral drugs are effective for treating herpes, including acyclovir, valaciclovir (valacyclovir), famciclovir, and penciclovir. Acyclovir was the first discovered and is now available in generic. Valacyclovir is also available as a generic and is slightly more effective than aciclovir for reducing lesion healing time.

Evidence supports the use of acyclovir and valacyclovir in the treatment of herpes labialis as well as herpes infections in people with cancer. The evidence to support the use of acyclovir in primary herpetic gingivostomatitis is weaker.