The disease may remain manageable, but in more severe cases, lymph nodes in the neck may swell, and breathing and swallowing are more difficult. People in this stage should seek immediate medical attention, as obstruction in the throat may require intubation or a tracheotomy. Abnormal cardiac rhythms can occur early in the course of the illness or weeks later, and can lead to heart failure. Diphtheria can also cause paralysis in the eye, neck, throat, or respiratory muscles. Patients with severe cases are put in a hospital intensive care unit and given a diphtheria antitoxin. Since antitoxin does not neutralize toxin that is already bound to tissues, delaying its administration is associated with an increase in mortality risk. Therefore, the decision to administer diphtheria antitoxin is based on clinical diagnosis, and should not await laboratory confirmation.

Antibiotics have not been demonstrated to affect healing of local infection in diphtheria patients treated with antitoxin. Antibiotics are used in patients or carriers to eradicate "C. diphtheriae" and prevent its transmission to others. The Centers for Disease Control and Prevention recommends either:

- Metronidazole

- Erythromycin is given (orally or by injection) for 14 days (40 mg/kg per day with a maximum of 2 g/d), or

- Procaine penicillin G is given intramuscularly for 14 days (300,000 U/d for patients weighing 10 kg); patients with allergies to penicillin G or erythromycin can use rifampin or clindamycin.

In cases that progress beyond a throat infection, diphtheria toxin spreads through the blood and can lead to potentially life-threatening complications that affect other organs, such as the heart and kidneys. Damage to the heart caused by the toxin affects the heart's ability to pump blood or the kidneys' ability to clear wastes. It can also cause nerve damage, eventually leading to paralysis. About 40% to 50% of those left untreated can die.

Empirical treatment should generally be started in a patient in whom suspicion of diphtheria is high.

Corticosteroids, such as dexamethasone and budesonide, have been shown to improve outcomes in children with all severities of croup. Significant relief is obtained as early as six hours after administration. While effective when given by injection, or by inhalation, giving the medication by mouth is preferred. A single dose is usually all that is required, and is generally considered to be quite safe. Dexamethasone at doses of 0.15, 0.3 and 0.6 mg/kg appear to be all equally effective.

Moderate to severe croup may be improved temporarily with nebulized epinephrine. While epinephrine typically produces a reduction in croup severity within 10–30 minutes, the benefits last for only about 2 hours. If the condition remains improved for 2–4 hours after treatment and no other complications arise, the child is typically discharged from the hospital.

Severe cases will require admission to intensive care. In addition to the measures listed above for mild tetanus:

- Human tetanus immunoglobulin injected intrathecally (increases clinical improvement from 4% to 35%)

- Tracheotomy and mechanical ventilation for 3 to 4 weeks. Tracheotomy is recommended for securing the airway because the presence of an endotracheal tube is a stimulus for spasm

- Magnesium, as an intravenous (IV) infusion, to prevent muscle spasm

- Diazepam as a continuous IV infusion

- The autonomic effects of tetanus can be difficult to manage (alternating hyper- and hypotension hyperpyrexia/hypothermia) and may require IV labetalol, magnesium, clonidine, or nifedipine

Drugs such as diazepam or other muscle relaxants can be given to control the muscle spasms. In extreme cases it may be necessary to paralyze the patient with curare-like drugs and use a mechanical ventilator.

In order to survive a tetanus infection, the maintenance of an airway and proper nutrition are required. An intake of 3,500 to 4,000 calories and at least 150 g of protein per day is often given in liquid form through a tube directly into the stomach (percutaneous endoscopic gastrostomy), or through a drip into a vein (parenteral nutrition). This high-caloric diet maintenance is required because of the increased metabolic strain brought on by the increased muscle activity. Full recovery takes 4 to 6 weeks because the body must regenerate destroyed nerve axon terminals.

Mild cases of tetanus can be treated with:

- tetanus immunoglobulin (TIG), also called "tetanus antibodies" or "tetanus antitoxin." It can be given as intravenous therapy or by intramuscular injection.

- metronidazole IV for 10 days

- diazepam oral or IV

"Haemophilus influenzae" produces beta-lactamases, and it is also able to modify its penicillin-binding proteins, so it has gained resistance to the penicillin family of antibiotics.

In severe cases, cefotaxime and ceftriaxone delivered directly into the bloodstream are the elected antibiotics, and, for the less severe cases, an association of ampicillin and sulbactam, cephalosporins of the second and third generation, or fluoroquinolones are preferred. (Fluoroquinolone-resistant "Haemophilus influenzae" have been observed.)

Macrolide antibiotics (e.g., clarithromycin) may be used in patients with a history of allergy to beta-lactam antibiotics. Macrolide resistance has also been observed.

The serious complications of HiB are brain damage, hearing loss, and even death.

Gargling salt water is often suggested but evidence looking at its usefulness is lacking. Alternative medicines are promoted and used for the treatment of sore throats. However, they are poorly supported by evidence.

The majority of time treatment is symptomatic. Specific treatments are effective for bacterial, fungal, and herpes simplex infections.

Prescribing antibiotics for laryngitis is not suggested practice. The antibiotics penicillin V and erythromycin are not effective for treating acute laryngitis. Erythromycin may improve voice disturbances after one week and cough after two weeks, however any modest subjective benefit is not greater than the adverse effects, cost, and the risk of bacteria developing resistance to the antibiotics. Health authorities have been strongly encouraging physicians to decrease the prescribing of antibiotics to treat common upper respiratory tract infections because antibiotic usage does not significantly reduce recovery time for these viral illnesses. Decreased antibiotic usage could also have prevented drug resistant bacteria. Some have advocated a delayed antibiotic approach to treating URIs which seeks to reduce the consumption of antibiotics while attempting to maintain patient satisfaction. Most studies show no difference in improvement of symptoms between those treated with antibiotics right away and those with delayed prescriptions. Most studies also show no difference in patient satisfaction, patient complications, symptoms between delayed and no antibiotics. A strategy of "no antibiotics" results in even less antibiotic use than a strategy of "delayed antibiotics".

The Centers for Disease Control describe protocol for treating sinusitis while at the same time discouraging overuse of antibiotics:

- Target likely organisms with first-line drugs: Amoxicillin, Amoxicillin/Clavulanate

- Use shortest effective course: Should see improvement in 2–3 days. Continue treatment for 7 days after symptoms improve or resolve (usually a 10–14 day course).

- Consider imaging studies in recurrent or unclear cases: some sinus involvement is frequent early in the course of uncomplicated viral URI

Treatment comprises symptomatic support usually via analgesics for headache, sore throat and muscle aches. Moderate exercise in sedentary subjects with naturally acquired URTI probably does not alter the overall severity and duration of the illness. No randomized trials have been conducted to ascertain benefits of increasing fluid intake.

Most sinusitis cases are caused by viruses and resolve without antibiotics. However, if symptoms do not resolve within 10 days, amoxicillin is a reasonable antibiotic to use first for treatment with amoxicillin/clavulanate being indicated when the person's symptoms do not improve after 7 days on amoxicillin alone. A 2012 Cochrane review, however, found only a small benefit between 7 and 14 days, and could not recommend the practice when compared to potential complications and risk of developing resistance. Antibiotics are specifically not recommended in those with mild / moderate disease during the first week of infection due to risk of adverse effects, antibiotic resistance, and cost.

Fluoroquinolones, and a newer macrolide antibiotic such as clarithromycin or a tetracycline like doxycycline, are used in those who have severe allergies to penicillins. Because of increasing resistance to amoxicillin the 2012 guideline of the Infectious Diseases Society of America recommends amoxicillin-clavulanate as the initial treatment of choice for bacterial sinusitis. The guidelines also recommend against other commonly used antibiotics, including azithromycin, clarithromycin, and trimethoprim/sulfamethoxazole, because of growing antibiotic resistance. The FDA recommends against the use of fluoroquinolones when other options are available due to higher risks of serious side effects.

A short-course (3–7 days) of antibiotics seems to be just as effective as the typical longer-course (10–14 days) of antibiotics for those with clinically diagnosed acute bacterial sinusitis without any other severe disease or complicating factors. The IDSA guideline suggest five to seven days of antibiotics is long enough to treat a bacterial infection without encouraging resistance. The guidelines still recommend children receive antibiotic treatment for ten days to two weeks.

For unconfirmed acute sinusitis, intranasal corticosteroids have not been found to be better than a placebo either alone or in combination with antibiotics. For cases confirmed by radiology or nasal endoscopy, treatment with corticosteroids alone or in combination with antibiotics is supported. The benefit, however, is small.

There is only limited evidence to support short treatment with oral corticosteroids for chronic rhinosinusitis with nasal polyps.

There is some low quality evidence suggesting that mometasone may lead to symptomatic improvement in children with adenoid hypertrophy.

Surgical removal of the adenoids is a procedure called adenoidectomy. Carried out through the mouth under a general anaesthetic, adenoidectomy involves the adenoids being curetted, cauterised, lasered, or otherwise ablated. Adenoidectomy is most often performed because of nasal obstruction, but is also performed to reduce middle ear infections and fluid (otitis media). The procedure is often carried out at the same time as a tonsillectomy, since the adenoids can be clearly seen and assessed by the surgeon at that time.

Antihistamine drugs can be taken orally and nasally to control symptoms such as sneezing, rhinorrhea, itching, and conjunctivitis.

It is best to take oral antihistamine medication before exposure, especially for seasonal allergic rhinitis. In the case of nasal antihistamines like azelastine antihistamine nasal spray, relief from symptoms is experienced within 15 minutes allowing for a more immediate 'as-needed' approach to dosage.

Ophthalmic antihistamines (such as azelastine in eye drop form and ketotifen) are used for conjunctivitis, while intranasal forms are used mainly for sneezing, rhinorrhea, and nasal pruritus.

Antihistamine drugs can have undesirable side-effects, the most notable one being drowsiness in the case of oral antihistamine tablets. First-generation antihistamine drugs such as diphenhydramine cause drowsiness, but second- and third-generation antihistamines such as cetirizine and loratadine are less likely to cause this problem.

Pseudoephedrine is also indicated for vasomotor rhinitis. It is used only when nasal congestion is present and can be used with antihistamines. In the United States, oral decongestants containing pseudoephedrine must be purchased behind the pharmacy counter by law in effort to prevent the making of methamphetamine.

Intranasal corticosteroids are used to control symptoms associated with sneezing, rhinorrhea, itching, and nasal congestion. Steroid nasal sprays are effective and safe, and may be effective without oral antihistamines. They take several days to act and so must be taken continually for several weeks, as their therapeutic effect builds up with time.

In 2013, a study compared the efficacy of mometasone furoate nasal spray to betamethasone oral tablets for the treatment of people with seasonal allergic rhinitis and found that the two have virtually equivalent effects on nasal symptoms in people.

Systemic steroids such as prednisone tablets and intramuscular triamcinolone acetonide or glucocorticoid (such as betamethasone) injection are effective at reducing nasal inflammation, but their use is limited by their short duration of effect and the side-effects of prolonged steroid therapy.

In most cases treatment for rhinorrhea is not necessary since it will clear up on its own—especially if it is the symptom of an infection. For general cases blowing your nose can get rid of the mucus buildup. Though blowing may be a quick-fix solution, it would likely proliferate mucosal production in the sinuses, leading to frequent and higher mucus buildups in the nose. Alternatively, saline nasal sprays and vasoconstrictor nasal sprays may also be used, but may become counterproductive after several days of use, causing rhinitis medicamentosa.

In recurring cases, such as those due to allergies, there are medicinal treatments available. For cases caused by histamine buildup, several types of antihistamines can be obtained relatively cheaply from drugstores.

People who prefer to keep clear nasal passages, such as singers, who need a clear nasal passage to perform, may use a technique called "nasal irrigation" to prevent rhinorrhea. Nasal irrigation involves rinsing the nasal cavity regularly with salty water or store bought saline solutions.

Antibiotics do not help the many lower respiratory infections which are caused by parasites or viruses. While acute bronchitis often does not require antibiotic therapy, antibiotics can be given to patients with acute exacerbations of chronic bronchitis. The indications for treatment are increased dyspnoea, and an increase in the volume or purulence of the sputum. The treatment of bacterial pneumonia is selected by considering the age of the patient, the severity of the illness and the presence of underlying disease. Amoxicillin and doxycycline are suitable for many of the lower respiratory tract infections seen in general practice.

In 2012, the World Health Organization estimated that vaccination prevents 2.5 million deaths each year. If there is 100% immunization, and 100% efficacy of the vaccines, one out of seven deaths among young children could be prevented, mostly in developing countries, making this an important global health issue. Four diseases were responsible for 98% of vaccine-preventable deaths: measles, "Haemophilus influenzae" serotype b, pertussis, and neonatal tetanus.

The Immunization Surveillance, Assessment and Monitoring program of the WHO monitors and assesses the safety and effectiveness of programs and vaccines at reducing illness and deaths from diseases that could be prevented by vaccines.

Vaccine-preventable deaths are usually caused by a failure to obtain the vaccine in a timely manner. This may be due to financial constraints or to lack of access to the vaccine. A vaccine that is generally recommended may be medically inappropriate for a small number of people due to severe allergies or a damaged immune system. In addition, a vaccine against a given disease may not be recommended for general use in a given country, or may be recommended only to certain populations, such as young children or older adults. Every country makes its own vaccination recommendations, based on the diseases that are common in its area and its healthcare priorities. If a vaccine-preventable disease is uncommon in a country, then residents of that country are unlikely to receive a vaccine against it. For example, residents of Canada and the United States do not routinely receive vaccines against yellow fever, which leaves them vulnerable to infection if travelling to areas where risk of yellow fever is highest (endemic or transitional regions).

The management of rhinitis depends on the underlying cause.

For allergic rhinitis, intranasal corticosteroids are recommended. For severe symptoms intranasal antihistamines may be added.

It is important that parents and caretakers remain calm, take first aid measures, and carefully observe the child. If a child is having a febrile seizure, parents and caregivers should do the following:

- Note the start time of the seizure. If the seizure lasts longer than 5 minutes, call an ambulance. The child should be taken immediately to the nearest medical facility for diagnosis and treatment.

- Call an ambulance if the seizure is less than 5 minutes but the child does not seem to be recovering quickly.

- Gradually place the child on a protected surface such as the floor or ground to prevent accidental injury. Do not restrain or hold a child during a convulsion.

- Position the child on his or her side or stomach to prevent choking. When possible, gently remove any objects from the child’s mouth. Nothing should ever be placed in the child's mouth during a convulsion. These objects can obstruct the child's airway and make breathing difficult.

- Seek immediate medical attention if this is the child’s first febrile seizure and take the child to the doctor once the seizure has ended to check for the cause of the fever. This is especially urgent if the child shows symptoms of stiff neck, extreme lethargy, or abundant vomiting, which may be signs of meningitis, an infection over the brain surface.

In those who have prolonged seizures intravenous lorazepam is recommended. The other benzodiazepines—midazolam and diazepam—are also reasonable options.

Reduction of hypertrophied turbinates, correction of nasal septum deviation, removal of polyps, sectioning of the parasympathetic secretomotor fiber to nose (vidian neurectomy) for controlling refractory excessive rhinorrhea.

There is no benefit from the use of phenytoin, valproate, pyridoxine, ibuprofen, zinc sulfate, diclofenac, acetaminophen.

There is a decrease of recurrent febrile seizures with intermittent diazepam and phenobarbital but there is a high rate of adverse effects. They are thus not recommended as an effort to prevent further seizures.

First-generation antihistamine has been suggested as first-line therapy to treat post-nasal drip.