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.

While other treatments for croup have been studied, none have sufficient evidence to support their use. Inhalation of hot steam or humidified air is a traditional self-care treatment, but clinical studies have failed to show effectiveness and currently it is rarely used. The use of cough medicines, which usually contain dextromethorphan or guaifenesin, are also discouraged. There is tentative evidence that breathing heliox (a mixture of helium and oxygen) to decrease the work of breathing is useful in those with severe disease. Since croup is usually a viral disease, antibiotics are not used unless secondary bacterial infection is suspected. In cases of possible secondary bacterial infection, the antibiotics vancomycin and cefotaxime are recommended. In severe cases associated with influenza A or B, the antiviral neuraminidase inhibitors may be administered.

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.

If the tonsillitis is caused by group A streptococcus, then antibiotics are useful, with penicillin or amoxicillin being primary choices. Cephalosporins and macrolides are considered good alternatives to penicillin in the acute setting. A macrolide such as erythromycin is used for people allergic to penicillin. Individuals who fail penicillin therapy may respond to treatment effective against beta-lactamase producing bacteria such as clindamycin or amoxicillin-clavulanate. Aerobic and anaerobic beta lactamase producing bacteria that reside in the tonsillar tissues can "shield" group A streptococcus from penicillins.

Chronic cases may be treated with tonsillectomy (surgical removal of tonsils) as a choice for treatment. Children have had only a modest benefit from tonsillectomy for chronic cases of tonsillitis.

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.

Acute infection does not usually require treatment and most adults clear the infection spontaneously. Early antiviral treatment may be required in fewer than 1% of people, whose infection takes a very aggressive course (fulminant hepatitis) or who are immunocompromised. On the other hand, treatment of chronic infection may be necessary to reduce the risk of cirrhosis and liver cancer. Chronically infected individuals with persistently elevated serum alanine aminotransferase, a marker of liver damage, and HBV DNA levels are candidates for therapy. Treatment lasts from six months to a year, depending on medication and genotype. Treatment duration when medication is taken by mouth, however, is more variable and usually longer than one year.

Although none of the available drugs can clear the infection, they can stop the virus from replicating, thus minimizing liver damage. As of 2008, there are seven medications licensed for the treatment of infection in the United States. These include antiviral drugs lamivudine (Epivir), adefovir (Hepsera), tenofovir (Viread), telbivudine (Tyzeka) and entecavir (Baraclude), and the two immune system modulators interferon alpha-2a and PEGylated interferon alpha-2a (Pegasys). In 2015 the World Health Organization recommended tenofovir or entecavir as first-line agents. Those with current cirrhosis are in most need of treatment.

The use of interferon, which requires injections daily or thrice weekly, has been supplanted by long-acting PEGylated interferon, which is injected only once weekly. However, some individuals are much more likely to respond than others, and this might be because of the genotype of the infecting virus or the person's heredity. The treatment reduces viral replication in the liver, thereby reducing the viral load (the amount of virus particles as measured in the blood). Response to treatment differs between the genotypes. Interferon treatment may produce an e antigen seroconversion rate of 37% in genotype A but only a 6% seroconversion in type D. Genotype B has similar seroconversion rates to type A while type C seroconverts only in 15% of cases. Sustained e antigen loss after treatment is ~45% in types A and B but only 25–30% in types C and D.

Treatment is usually supportive only, as the disease is self-limiting and usually runs its course in less than a week.

During the latest outbreak of the disease (2004), several treatment methods were tested. Main treatment involved the administration of antibiotics, in some cases glucose solution or dietary mixtures were additionally supplemented. Outcome of the different treatment methods varied greatly. Especially the success of antibiotic treatment and a widespread use on wild animals remains a matter of debate.

In assisted reproductive technology, sperm washing is not necessary for males with hepatitis B to prevent transmission, unless the female partner has not been effectively vaccinated. In females with hepatitis B, the risk of transmission from mother to child with IVF is no different from the risk in spontaneous conception.

Those at high risk of infection should be tested as there is effective treatment for those who have the disease. Groups that screening is recommended for include those who have not been vaccinated and one of the following: people from areas of the world where hepatitis B occurs in more than 2%, those with HIV, intravenous drug users, men who have sex with men, and those who live with someone with hepatitis B.

Due to its rarity, no comprehensive treatment studies on eosinophilic myocarditis have been conducted. Small studies and case reports have directed efforts towards: a) supporting cardiac function by relieving heart failure and suppressing life-threatening abnormal heart rhythms; b) suppressing eosinophil-based cardiac inflammation; and c) treating the underlying disorder. In all cases of symptomatic eosinophilic myocarditis that lack specific treatment regimens for the underlying disorder, available studies recommend treating the inflammatory component of this disorder with non-specific immunosuppressive drugs, principally high-dosage followed by slowly-tapering to a low-dosage maintenance corticosteroid regimens. It is recommended that afflicted individuals who fail this regimen or present with cardiogenic shock be treated with other non-specific immunosuppressive drugs viz., azathioprine or cyclophosphamide, as adjuncts to, or replacements for, corticosteroids. However, individuals with an underlying therapeutically accessible disease should be treated for this disease; in seriously symptomatic cases, such individuals may be treated concurrently with a corticosteroid regimen. Examples of diseases underlying eosinophilic myocarditis that are recommended for treatments directed at the underlying disease include:

- Infectious agents: specific drug treatment of helminth and protozoan infections typically takes precedence over non-specific immunosuppressive therapy, which, if used without specific treatment, could worsen the infection. In moderate-to-severe cases, non-specific immunosuppression is used in combination with specific drug treatment.

- Toxic reactions to ingested agents: discontinuance of the ingested agent plus corticosteroids or other non-specific immunosuppressive regimens.

- Clonal eosinophilia caused by mutations in genes that are highly susceptible to tyrosine kinase inhibitors such as "PDGFRA", "PDGFRB", or possibly "FGFR1": first generation tyrosine kinase inhibitors (e.g. imatinib) are recommended for the former two mutations; a later generation tyrosine kinase inhibitors, ponatinib, alone or combined with bone marrow transplantation, may be useful for treating the FGFR1 mutations.

- Clonal hypereosinophilia due to mutations in other genes or primary malignancies: specific treatment regimens used for these pre-malignant or malignant diseases may be more useful and necessary than non-specific immunosuppression.

- Allergic and autoimmune diseases: non-specific treatment regimens used for these diseases may be useful in place of a simple corticosteroid regimen. For example, eosinophilic granulomatosis with polyangiitis can be successfully treated with mepolizumab.

- Idiopathic hypereosinphilic syndrome and lymphocyte-variant hypereosinophilia: corticosteroids; for individuals with these hypereosinophilias that are refractory to or break through corticosteroid therapy and individuals requiring corticosteroid-sparing therapy, recommended alternative drug therapies include hydroxyurea, Pegylated interferon-α, and either one of two tyrosine kinase inhibitors viz., imatinib and mepolizumab).

A diagnosis can be made from clinical signs and symptoms, and treatment consists of minimizing the discomfort of symptoms. It can be differentiated from herpetic gingivostomatitis by the positioning of vesicles - in herpangina, they are typically found on the posterior oropharynx, as compared to gingivostomatitis where they are typically found on the anterior oropharynx and the mouth.

Treatment involves appropriate antibiotic medications, monitoring and protection of the airway in severe cases, and, where appropriate, urgent Otolaryngology-Head and Neck Surgery, maxillo-facial surgery and/or dental consultation to incise and drain the collections. The antibiotic of choice is from the penicillin group.

Incision and drainage of the abscess may be either intraoral or external. An intraoral incision and drainage procedure is indicated if the infection is localized to the sublingual space. External incision and drainage is performed if infection involves the perimandibular spaces.

A nasotracheal tube is sometimes warranted for ventilation if the tissues of the mouth make insertion of an oral airway difficult or impossible.

In cases where the patency of the airway is compromised, skilled airway management is mandatory. Fiberoptic intubation is common.

Ludwig's angina is a life-threatening condition, and carries a fatality rate of about 5%.

Diphtheritic stomatitis is a recently discovered disease and has thus far been reported only in Yellow-eyed penguins ("Megadyptes antipodes"). Its symptoms are similar to human diphtheria and is characterized by infecteous lesions in the mouth area that impede swallowing and cause respiratory troubles. The infection is caused by "Corynebacterium amycolatum", an aerobic Gram-positive bacterium and mainly affects very young chicks. However, it seems likely that a triggering agent (e.g. a virus) might be involved in which renders the corynebacterium a secondary pathogen.

The disease has been a serious cause of mortality in the 2002 and 2004 Yellow-eyed penguin breeding seasons. It seems that only the New Zealand South Island and Stewart Island/Rakiura were affected.

Treatment includes irrigation and debridement of necrotic areas (areas of dead and/or dying gum tissue), oral hygiene instruction and the uses of mouth rinses and pain medication. If there is systemic involvement, then oral antibiotics may be given, such as metronidazole. As these diseases are often associated with systemic medical issues, proper management of the systemic disorders is appropriate.

Treatment of secondary membranous nephropathy is guided by the treatment of the original disease. For treatment of idiopathic membranous nephropathy, the treatment options include immunosuppressive drugs and non-specific anti-proteinuric measures. Recommended first line therapy often includes: cyclophosphamide alternating with a corticosteroid.

Aggressive risk factor modification is required for effective treatment of microvascular angina where exercise plays a major role. Several other treatment strategies including b-blockers, angiotensin-converting enzyme inhibitors, ranolazine, l-arginine, statin drugs and potentially estrogen replacement therapy have been shown to relieve anginal symptoms as well as improve vascular function. Nitrates may be effective for symptom relief. Further studies are required to determine whether specific treatments are associated with improved survival as well as decreased symptoms.

It is recommended that blood pressure typically be reduced to less than 140/90 mmHg. The diastolic blood pressure however should not be lower than 60 mmHg. Beta blockers are recommended first line for this use.

Perhaps the most difficult aspect of membranous glomerulonephritis is deciding which people to treat with immunosuppressive therapy as opposed to simple "background" or anti-proteinuric therapies. A large part of this difficulty is due to a lack of ability to predict which people will progress to end-stage renal disease, or renal disease severe enough to require dialysis. Because the above medications carry risk, treatment should not be initiated without careful consideration as to risk/benefit profile. Of note, corticosteroids (typically Prednisone) alone are of little benefit. They should be combined with one of the other 5 medications, each of which, along with prednisone, has shown some benefit in slowing down progression of membranous nephropathy. It must be kept in mind, however, that each of the 5 medications also carry their own risks, on top of prednisone.

The twin aims of treating membranous nephropathy are first to induce a remission of the nephrotic syndrome and second to prevent the development of endstage renal failure. A meta-analysis of four randomized controlled studies comparing treatments of membranous nephropathy showed that regimes comprising chlorambucil or cyclophosphamide, either alone or with steroids, were more effective than symptomatic treatment or treatment with steroids alone in inducing remission of the nephrotic syndrome.

Therapeutic interventions with medium-chain triglyceride-enriched low-fat diets, intratracheal heparin, inhaled tissue plasminogen activator, and steroids have also been reported and have met with variable success.

Inhaled mucolytics: Potassium iodide and acetylcysteine inhaled therapy are often used to help the patient cough up the casts by breaking down the thick mucus formations.

Inhaled and oral steroids: If PB is associated with asthma or an infection, inhaled and oral steroids have been shown to be effective.

Drug regimens prescribed for lupus nephritis include mycophenolate mofetil (MMF), intravenous cyclophosphamide with corticosteroids, and the immune suppressant azathioprine with corticosteroids. MMF and cyclophosphamide with corticosteroids are equally effective in achieving remission of the disease. MMF is safer than cyclophosphamide with corticosteroids, with less chance of causing ovarian failure, immune problems or hair loss. It also works better than azathioprine with corticosteroids for maintenance therapy. Individuals with lupus nephritis have a high risk for B-cell lymphoma (which begins in the immune system cells).

Treatment of the primary gastroenterological distress is the first concern, mitigation of gastric symptoms will also alleviate cardiac distress.

- Anticholinergics, magnesium, or sodium (to raise blood pressure) supplements

- Anticonvulsants have eliminated all symptoms in some RS sufferers; Lorazepam, Oxcarbazepine increase GI motility, reduce vagus "noise" (sodium channel blocking believed to contribute to positive effects)

- Alpha blockers may increase gi motility if that is an issue, also 5 mg to 10 mg amitriptyline if motility is an issue that can't be solved by other methods

- antigas - simethicone, beano, omnimax reduces epigastric pressure

- Antacids - nexium, tums, Pepcid AC, rolaids, etc. reduces acid reflux in the case of hiatal hernia or other esophageal type RS.

- Vagusectomy

- Beta blockers - reduces contractility and automaticity of the heart which reduces irregular rhythms but also lowers blood pressure when symptoms occur, and further reduces perfusion ex: Atenolol, this will control disarrhythmia, but can precipitate Prinzmetal Angina and Heart block substantially.

There are a number of treatment options for coronary artery disease:

- Lifestyle changes

- Medical treatment – drugs (e.g., cholesterol lowering medications, beta-blockers, nitroglycerin, calcium channel blockers, etc.);

- Coronary interventions as angioplasty and coronary stent;

- Coronary artery bypass grafting (CABG)