Hyperalgesia is similar to other sorts of pain associated with nerve irritation or damage such as allodynia and neuropathic pain, and consequently may respond to standard treatment for these conditions, using various drugs such as SSRI or tricyclic antidepressants, Nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, gabapentin or pregabalin, NMDA antagonists, or atypical opioids such as tramadol. Where hyperalgesia has been produced by chronic high doses of opioids, reducing the dose may result in improved pain management. However, as with other forms of nerve dysfunction associated pain, treatment of hyperalgesia can be clinically challenging, and finding a suitable drug or drug combination that is effective for a particular patient may require trial and error. The use of a transcutaneous electrical nerve stimulation device has been shown to alleviate hyperalgesia.

Numerous compounds alleviate the pain from allodynia. Some are specific for certain types of allodynia while others are general. They include:

- Dynamic mechanical allodynia - compounds targeting different ion channels; opioids

- Mexiletine

- Lidocaine (IV/topical)

- Tramadol

- Morphine (IV)

- Alfentanil (IV)

- Ketamine (IV)

- Methylprednisone (intrathecal)

- Adenosine

- Glycine antagonist

- Desipramine

- Venlafaxine

- Lyrica

- Static mechanical allodynia - sodium channel blockers, opioids

- Lidocaine (IV)

- Alfentanil (IV)

- Adenosine (IV)

- Ketamine (IV)

- Glycine antagonist

- Venlafaxine

- Gabapentin (may also be helpful in cold and dynamic allodynias)

- Cold allodynia

- Lamotrigine

- Lidocaine (IV)

The list of compounds that can be used to treat allodynia is even longer than this. For example, many non-steroidal anti-inflammatory drugs, such as naproxen, can inhibit COX-1 and/or COX-2, thus preventing the sensitization of the central nervous system. Another effect of naproxen is the reduction of the responsiveness of mechano- and thermoreceptors to stimuli.

Other compounds act on molecules important for the transmission of an action potential from one neuron to another. Examples of these include interfering with receptors for neurotransmitters or the enzymes that remove neurotransmitters not bound to receptors.

Endocannabinoids are molecules that can relieve pain by modulating nociceptive neurons. When anandamide, an endocannabinoid, is released, pain sensation is reduced. Anandamide is later transported back to the neurons releasing it using transporter enzymes on the plasma membrane, eventually disinhibiting pain perception. However, this re-uptake can be blocked by AM404, elongating the duration of pain inhibition.

Hyperalgesia ( or ; 'hyper' from Greek ὑπέρ (huper, “over”), '-algesia' from Greek algos, ἄλγος (pain)) is an increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves. Prostaglandins E and F are largely responsible for sensitizing the nociceptors. Temporary increased sensitivity to pain also occurs as part of sickness behavior, the evolved response to infection.

Allodynia is a clinical feature of many painful conditions, such as neuropathies, complex regional pain syndrome, postherpetic neuralgia, fibromyalgia, and migraine. Allodynia may also be caused by some populations of stem cells used to treat nerve damage including spinal cord injury. Static mechanical allodynia is a paradoxical painful hypoaesthesia, one etiology of which is lesions of A-beta fibers.

As of 2013 low quality evidence supports the use of bisphosphonates. A 2009 review found "very limited data reviewed showed that bisphosphonates have the potential to reduce pain associated with bone loss in patients with CRPS I, however, at present there is not sufficient evidence to recommend their use in practice".

Treatment of opioid tolerance and Opioid-Induced Hyperalgesia (OIH) differs but it may be difficult to differentiate these two conditions in a clinical setting where most pain assessments are done through simple scale scores. The treatment for OIH may be challenging because an inadequate number of quality studies exists possibly due to the complexity in diagnosis of OIH and challenges in working with patients on chronic opioids. Currently there is no single best treatment method for OIH and clinicians are advised to choose an appropriate therapy based on the unique clinical scenario and history of each patient.

One general treatment option is to reduce or discontinue the dose of opioid to see if OIH is improved. Opioid sparing or opioid switching, which is replacing the current opioid with another pharmacological agent such as morphine or methadone, has been reported to be effective in some studies but this may also increase the sensitivity to pain according to some case reports. Ketamine, a NMDA antagonist, has been shown to prevent the extended use of opioid in post-operative hyperalgesia when it is infused in a small amount perioperatively along with the opioid but there are also studies that show ketamine being ineffective in modulating hyperalgesia. Addition of the NSAID, especially some COX-2 inhibitors, or acetaminophen is also suggested as a possible treatment option.

Tentative evidence supports the use of bisphosphonates, calcitonin, and ketamine. Doing nerve blocks with guanethidine appears to be harmful. Evidence for sympathetic nerve blocks generally is insufficient to support their use. Intramuscular botulinum injections may benefit people with symptoms localized to one extremity.

Opioid-induced hyperalgesia or opioid-induced abnormal pain sensitivity, also called paradoxical hyperalgesia is a phenomenon associated with the long-term use of opioids such as morphine, hydrocodone, oxycodone, and methadone. Over time, individuals taking opioids can develop an increasing sensitivity to noxious stimuli, even evolving a painful response to previously non-noxious stimuli (allodynia). Some studies on animals have also demonstrated this effect occurring after only a single high dose of opioids.

Tolerance, another condition that can arise from prolonged exposure to opioids, can often be mistaken for opioid-induced hyperalgesia and vice-versa, as the clinical presentation can appear similar. Although tolerance and opioid-induced hyperalgesia both result in a similar need for dose escalation to receive the same level of effect to treat pain, they are nevertheless caused by two distinct mechanisms. The similar net effect makes the two phenomena difficult to distinguish in a clinical setting. Under chronic opioid treatment, a particular individual's requirement for dose escalation may be due to tolerance, opioid-induced hyperalgesia, or a combination of both. In tolerance, there is a lower sensitivity to opioids, which occurs via two major theories: decreased receptor activation (desensitization of antinociceptive mechanisms), and opioid receptor down-regulation (internalization of membrane receptors). In opioid-induced hyperalgesia, sensitization of pronociceptive mechanisms occurs, resulting in a decrease in the pain threshold, or allodyna. Identifying the development of hyperalgesia is of great clinical importance since patients receiving opioids to relieve pain may paradoxically experience more pain as a result of treatment. Whereas increasing the dose of opioid can be an effective way to overcome tolerance, doing so to compensate for opioid-induced hyperalgesia may worsen the patient's condition by increasing sensitivity to pain while escalating physical dependence.

The phenomenon is common among palliative care patients following a too rapid escalation of opioid dosage.

Hyperpathia is a clinical symptom of certain neurological disorders wherein nociceptive stimuli evoke exaggerated levels of pain. This should not be confused with allodynia, where normally non-painful stimuli evoke pain.

Hyperpathia describes the neuropathic pain which the pain threshold on one hand is elevated and the other hand is central hyperexcited whenever there is a loss of fibres. Hyperpathia is underlying the peripheral or central deafferentation when the afferent inputs are lost. Hyperpathia only occurs on neuropathic pain patients with the loss of fibres.

The International Association of the Study of Pain’s (IASP) definition of hyperpathia is that: "A painful syndrome characterized by an abnormally painful reaction to a stimulus, "especially a repetitive stimulus, as well as an increased threshold." The definition also complies with a note which is: "It may occur with allodynia, hyperesthesia, hyperalgesia, or dysesthesia. Faulty identification and localization of the stimulus, delay, radiating sensation, and after-sensation may be present, and the pain is often explosive in character. The changes in this note are the specification of allodynia and the inclusion of hyperalgesia explicitly. Previously hyperalgesia was implied, since hyperesthesia was mentioned in the previous note and hyperalgesia is a special case of hyperesthesia".

CVAC sessions

Cyclic Variations in Adaptive Conditioning (CVAC) is a method of touch free cyclic hypobaric pneumatic compression for treatment of tissue edema and, therefore, edema-associated pain. As a pilot study, 10 participants with AD completed pain and quality of life questionnaires before and after 20–40 minutes of CVAC process daily for 5 days. After treatment, there was a significant decrease in pain as measured by the Pain Catastrophizing Scale and the Visual Analogue Scale, but there was no change in pain quality by the McGill Pain Questionnaire. However, there were no changes in the Pain Disability Index or Pittsburgh Sleep Quality Index. This study suggests a potential treatment role for CVAC, and the authors recommended randomized controlled clinical trials.

Recent research into treatments for Dercum's disease has identified liposuction as a possible treatment. The researchers wanted to assess the use of liposuction on the affected adipose tissue to see if pain was reduced in the affected patient. The results of this study suggested that pain was reduced in patients for a short period of time. As time had passed the patients pain level had once again increased. The study found that pain was reduced only for a period of time and that all symptoms had come back within 5 years. Other recent treatments include Transcutaneous Electrical Stimulation has in one case proven to safely and effectively reduce the symptoms of the disease. This type of therapy is typically used in the treatment of painful inflammatory conditions. Treatments included 10 consecutive sessions over a 6-month period. After 4 months of treatment pain was reduced and after 6 months of treatment pain was even further reduced.

Treatment consists of several such anesthetic injections, sometimes combined with corticosteroids. Such an approach yields persistent pain relief in two-thirds of patients. This beneficial effect on pain has been demonstrated in a prospective double blind trial. The physical volume of the injection may also break apart the adhesions or fibrosis responsible for the entrapment symptoms.

Patients who do not respond to a stratagem of repetitive local trigger point injections can be offered a surgical approach. Terminal branches of an intercostal nerve are removed at the level of the anterior sheath of the rectus abdominal muscle ('anterior neurectomy'). Several larger series demonstrated a successful response in approximately two out of three patients, which was confirmed in another prospective double blind surgical trial: 73% of the patients who underwent a neurectomy were pain free, compared to 18% in the non-nerve resected group. Patients not responding to an anterior neurectomy, or those in whom the pain syndrome recurs after an initial pain free period (10%) may choose to undergo secondary surgery. This involves a repeated exploration combined with a posterior neurectomy. This procedure has been shown to be beneficial in 50% of cases.

Though evidence for acupuncture is slight, some suggest it may be useful in those with frequent or chronic tension headaches.

People with tension-type headache often use spinal manipulation, soft tissue therapy, and myofascial trigger point treatment. Studies of effectiveness are mixed. A 2006 systematic review found no rigorous evidence supporting manual therapies for tension headache. A 2005 structured review found only weak evidence for the effectiveness of chiropractic manipulation for tension headache, and that it was probably more effective for tension headache than for migraine. A 2004 Cochrane review found that spinal manipulation may be effective for migraine and tension headache, and that spinal manipulation and neck exercises may be effective for cervicogenic headache. Two other systematic reviews published between 2000 and May 2005 did not find conclusive evidence in favor of spinal manipulation. A 2012 systematic review of manual therapy found that hands-on work may reduce both the frequency and the intensity of chronic tension-type headaches.

Over-the-counter drugs, like acetaminophen, aspirin, or ibuprofen, can be effective but tend to only be helpful as a treatment for a few times in a week at most. Analgesic/sedative combinations are widely used (e.g., analgesic/antihistamine combinations like Syndol, Mersyndol and Percogesic, analgesic/barbiturate combinations such as Fiorinal). Frequent use of analgesics may, however, lead to medication overuse headache.

Botulinum toxin does not appear to be helpful.

This syndrome is predominantly found in young women, but also occurs in children, teenagers and octogenarians.

Since most toothache is the result of plaque-related diseases, such as tooth decay and periodontal disease, the majority of cases could be prevented by avoidance of a cariogenic diet and maintenance of good oral hygiene. That is, reduction in the number times that refined sugars are consumed per day and brushing the teeth twice a day with fluoride toothpaste and flossing. Regular visits to a dentist also increases the likelihood that problems are detected early and averted before toothache occurs. Dental trauma could also be significantly reduced by routine use of mouthguards in contact sports.

Approximately 280 million people globally, 4% of the population, have difficulty with itchiness. This is comparable to the 2–3% of the population suffering from psoriasis.

A variety of over-the-counter and prescription anti-itch drugs are available. Some plant products have been found to be effective anti-pruritics, others not. Non-chemical remedies include cooling, warming, soft stimulation.

Topical antipruritics in the form of creams and sprays are often available over-the-counter. Oral anti-itch drugs also exist and are usually prescription drugs. The active ingredients usually belong to the following classes:

- Antihistamines, such as diphenhydramine (Benadryl)

- Corticosteroids, such as hydrocortisone topical cream; "see" topical steroid

- Counterirritants, such as mint oil, menthol, or camphor

- Crotamiton (trade name Eurax) is an antipruritic agent available as a cream or lotion, often used to treat scabies. Its mechanism of action remains unknown.

- Local anesthetics, such as benzocaine topical cream (Lanacane)

Phototherapy is helpful for severe itching, especially if caused by renal failure. The common type of light used is UVB.

Sometimes scratching relieves isolated itches, hence the existence of devices such as the back scratcher. Often, however, scratching can intensify itching and even cause further damage to the skin, dubbed the "itch-scratch-itch cycle."

The mainstay of therapy for dry skin is maintaining adequate skin moisture and topical emollients.

In-office treatments may be much more complex and they may include the application of dental sealants, having fillings put over the exposed root that is causing the sensitivity, or a recommendation to wear a specially made night guard or retainer if the problems are a result of teeth grinding.

Other possible treatments include fluorides are also used because they decrease permeability of dentin "in vitro". Also, potassium nitrate can be applied topically in an aqueous solution or an adhesive gel. Oxalate products are also used because they reduce dentin permeability and occlude tubules more consistently. However, while some studies have showed that oxalates reduced sensitivity, others reported that their effects did not differ significantly from those of a placebo. Nowadays, dentin hypersensitivity treatments use adhesives, which include varnishes, bonding agents and restorative materials because these materials offer improved desensitization.

Low-output lasers are also suggested for dentin hypersensitivity, including GaAlAs lasers and . They are thought to act by producing a transient reduction in action potential in C-fibers in the pulp, but Aδ-fibers are not affected.

There are many causes of toothache and its diagnosis is a specialist topic, meaning that attendance at a dentist is usually required. Since many cases of toothache are inflammatory in nature, over the counter non-steroidal anti-inflammatory drugs (NSAIDs) may help (unless contraindicated, such as with a peptic ulcer). Generally, NSAIDs are as effective as aspirin alone or in combination with codeine. However, simple analgesics may have little effect on some causes of toothache, and the severe pain can drive individuals to exceed the maximum dose. For example, when acetaminophen (paracetamol) is taken for toothache, an accidental overdose is more likely to occur when compared to people who are taking acetaminophen for other reasons. Another risk in persons with toothache is a painful chemical burn of the oral mucosa caused by holding a caustic substance such as aspirin tablets and toothache remedies containing eugenol (such as clove oil) against the gum. Although the logic of placing a tablet against the painful tooth is understandable, an aspirin tablet needs to be swallowed to have any pain-killing effect. Caustic toothache remedies require careful application to the tooth only, without coming into excessive contact with the soft tissues of the mouth.

For the dentist, the goal of treatment generally is to relieve the pain, and wherever possible to preserve or restore function. The treatment depends on the cause of the toothache, and frequently a clinical decision regarding the current state and long-term prognosis of the affected tooth, as well as the individual's wishes and ability to cope with dental treatment, will influence the treatment choice. Often, administration of an intra-oral local anesthetic such as lidocaine and epinephrine is indicated in order to carry out pain-free treatment. Treatment may range from simple advice, removal of dental decay with a dental drill and subsequent placement of a filling, to root canal treatment, tooth extraction, or debridement.

At-home treatments include desensitizing toothpastes or dentifrices, potassium salts, mouthwashes and chewing gums.

A variety of toothpastes are marketed for dentin hypersensitivity, including compounds such as strontium chloride, strontium acetate, arginine, calcium carbonate, hydroxyapatite and calcium sodium phosphosilicate. Desensitizing chewing gums and mouthwashes are also marketed.

Potassium-containing toothpastes are common; however, the mechanism by which they may reduce hypersensitivity is unclear. Animal research has demonstrated that potassium ions placed in deep dentin cavities cause nerve depolarization and prevent re-polarization. It is not known if this effect would occur with the twice-daily, transient and small increase in potassium ions in saliva that brushing with potassium-containing toothpaste creates. In individuals with dentin hypersensitivity associated with exposed root surfaces, brushing twice daily with toothpaste containing 5% potassium nitrate for six to eight weeks reduces reported sensitivity to tactile, thermal and air blast stimuli. However, meta analysis reported that these individuals' subjective report of sensitivity did not significantly change after six to eight weeks of using the potassium nitrate toothpaste.

Desensitizing toothpastes containing potassium nitrate have been used since the 1980s while toothpastes with potassium chloride or potassium citrate have been available since at least 2000. It is believed that potassium ions diffuse along the dentinal tubules to inactivate intradental nerves. However, , this has not been confirmed in intact human teeth and the desensitizing mechanism of potassium-containing toothpastes remains uncertain. Since 2000, several trials have shown that potassium-containing toothpastes can be effective in reducing dentin hypersensitivity, although rinsing the mouth after brushing may reduce their efficacy.

Studies have found that mouthwashes containing potassium salts and fluorides can reduce dentine hypersensitivity, although rarely to any significant degree. , no controlled study of the effects of chewing gum containing potassium chloride has been made, although it has been reported as significantly reducing dentine hypersensitivity.

Nano-hydroxyapatite (nano-HAp) is considered one of the most biocompatible and bioactive materials, and has gained wide acceptance in dentistry in recent years. An increasing number of reports have shown that nano-hydroxyapatite shares characteristics with the natural building blocks of enamel having the potential, due to its particle size, to occlude exposed dentinal tubules helping to reduce hypersensitivity and enhancing teeth remineralization.

For this reason, the number of toothpastes and mouthwashes that already incorporate nano-hydroxyapatite as a desensitizing agent is increasing.

There is considerable research into the causes, diagnosis and treatments for FGIDs. Diet, microbiome, genetics, neuromuscular function and immunological response all interact. Heightened mast cell activation has been proposed to be a common factor among FGIDs, contributing to visceral hypersensitivity as well as epithelial, neuromuscular, and motility dysfunction.

Inflammation (from Latin "") is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and initiate tissue repair.

The classical signs of inflammation are heat, pain, redness, swelling, and loss of function. Inflammation is a generic response, and therefore it is considered as a mechanism of innate immunity, as compared to adaptive immunity, which is specific for each pathogen. Too little inflammation could lead to progressive tissue destruction by the harmful stimulus (e.g. bacteria) and compromise the survival of the organism. In contrast, chronic inflammation may lead to a host of diseases, such as hay fever, periodontitis, atherosclerosis, rheumatoid arthritis, and even cancer (e.g., gallbladder carcinoma). Inflammation is therefore normally closely regulated by the body.

Inflammation can be classified as either "acute" or "chronic". "Acute inflammation" is the initial response of the body to harmful stimuli and is achieved by the increased movement of plasma and leukocytes (especially granulocytes) from the blood into the injured tissues. A series of biochemical events propagates and matures the inflammatory response, involving the local vascular system, the immune system, and various cells within the injured tissue. Prolonged inflammation, known as "chronic inflammation", leads to a progressive shift in the type of cells present at the site of inflammation, such as mononuclear cells, and is characterized by simultaneous destruction and healing of the tissue from the inflammatory process.

Inflammation is not a synonym for infection. Infection describes the interaction between the action of microbial invasion and the reaction of the body's inflammatory response — the two components are considered together when discussing an infection, and the word is used to imply a microbial invasive cause for the observed inflammatory reaction. Inflammation on the other hand describes purely the body's immunovascular response, whatever the cause may be. But because of how often the two are correlated, words ending in the suffix "" (which refers to inflammation) are sometimes informally described as referring to infection. For example, the word "urethritis" strictly means only "urethral inflammation", but clinical health care providers usually discuss urethritis as a urethral infection because urethral microbial invasion is the most common cause of urethritis.

It is useful to differentiate inflammation and infection as there are many pathological situations where inflammation is not driven by microbial invasion – for example, atherosclerosis, type III hypersensitivity, trauma, ischaemia. There are also pathological situations where microbial invasion does not result in classic inflammatory response—for example, parasitosis, eosinophilia.

Inflammation is usually indicated by adding the suffix "", as shown below. However, some conditions such as asthma and pneumonia do not follow this convention. More examples are available at list of types of inflammation.