Why the skin is sensitive to touch? Acupuncture reduces pain

Allodynia is a condition in which someone experiences pain in the skin from non-painful stimuli, such as a light touch to the skin. Allodynia can be a symptom of different conditions, or it can occur on its own.

The main symptom of allodynia is pain from non-painful stimuli.

Some people with allodynia may experience severe pain with gentle pressure. Symptoms can vary from mild to severe. Some people may feel a burning sensation while others feel an ache or squeezing pain. Other symptoms accompanied can be depression, anxiety, insomnia, fatigue, not concentrating etc.

Some underlying conditions can cause allodynia. It’s most commonly linked to fibromyalgia and migraine headaches. Postherpetic neuralgia or peripheral neuropathy can also cause it.

The exact cause of allodynia is not known.

Allodynia may occur due to increased responsiveness or malfunction of sensory nerves and receptors.

Acupuncture can help reduce pain.

What is referred pain?

Referred pain is the pain felt in somewhere in the body other than in the site of origin. For example, teeth pain can be felt during heart attack. This teeth pain is referred pain, not the source of pain. The presence of pain in the teeth or jaws doesn't mean that there is any dental condition that needs to be treated, if there is no dental pain history. This is a typical example of referred pain which is pain felt at a site distant from the site of origin. Referred pain is frequently found in patients with chronic musculoskeletal pain (for example, temporomandibular disorder (TMD). In patients with TMD muscle and/or jaw joint pain could refer to the teeth. Patients and clinicians alike can become convinced that the pain is actually due to some form of dental problems. In these circumstances, treating teeth has no effect on the pain.

Pain referral has a neural basis. Specific pathways and neural connections in the brain are thought to lead to the possibility of pain referral.

One group of nerve fibres conduct information about touch and another group conduct information about tissue damage or noxious stimulation via different sensory nerves. Many sensory fibres from different parts of the different area can terminate on the same set of second order neurons. The second order neurones are part of the pathway that sends sensory information to higher centres for perception. However, since there is so much convergence of sensory information from different body parts onto the same second order neurones, these second order neurones may provide ambiguous information as to the exact location of the noxious stimulus. This neural mechanism is thought to be one way whereby the higher centres of the brain can become "confused" as to the exact location of the noxious stimulus.

Another explanation of pain referral is the activating of silent or latent synaptic connections. When there is prolonged and/or intense noxious stimulation, some of these ineffective synapses may become effective connections. The information is transmitted from other parts unrelated to the source of the pain. The brain therefore can become confused as to the correct location of the pain.

There is a simple diagnostic test that can be done to help distinguish referred pain to a tooth. Clinicians can use a diagnostic local anaesthetic to produce a neural inactivation at the site where the patient complains of the pain, e.g. a tooth. If the pain being felt in the tooth is referred pain, then the pain should persist despite the local anaesthetic. Locating the origin of pain is a key step for further treatment.

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4327510/

What is pain sensitisation?

Pain is a sensation of hurt resulting from the activation of pain pathways by harmful stimuli to lead to tissue damage. Detection of the stimuli is a protective process to help the body prevent injury or to avoid further contact with the stimuli. However in many clinical conditions the pain is no longer protective, but causes harm. The pain in these situations arises spontaneously, can be elicited by normally innocuous stimuli, is exaggerated and prolonged in response to noxious stimuli and spreads beyond the site of injury. This is caused by pain sensitization. There are two types of sensitizations: peripheral sensitization is a reduction in threshold and amplification in the responsiveness of pain receptors. This occurs when the receptors are exposed to inflammatory mediators and damaged tissue. Central sensitization is an enhancement in the function of neurons and circuits in pain pathways. This is caused by increases in membrane excitability and synaptic efficacy as well as to reduced inhibition in central nervous system in response to activity, inflammation, and neural injury. As a result previous non harmful stimuli generate amplified signals. Central sensitization is responsible for many of the temporal, spatial, and threshold changes in pain sensibility in acute and chronic clinical pain settings and exemplifies the fundamental contribution of the central nervous system to the generation of pain hypersensitivity.

Pelvic fascia and fascia inflammation

The fascia is connective tissue made up with collagen. The fascia can be seen between muscles, bones, ligaments and other internal organs. The pelvic fascia is the fascia surrounding the pelvis that line the walls and floor of the pelvis and covers pelvic floor muscles and pelvic organs such as the bladder, cervix and vagina in female and the prostate in male and rectum. The bladder and urethra and the vagina and uterus are attached to the pelvic walls by the pelvic fascia. This fascia lies immediately beneath the peritoneum and is continuous with various thickenings or condensations in specific areas. The fascia has myofibroblasts which have contractile ability and this active contraction is controlled by a nerve supply. The fascia inflammation stimulates fascia contracting which contributing to the muscle tightness and muscle tension and pain to surrounding region from the vulval area. Pelvic fascia inflammation can also irritate the bladder causing painful urination, frequent urination. The inflammation can also cause disturbed menstrual cycles. Acupuncture can reduce inflammation and improves the pain, urination pain, frequent urination and restore menstrual cycles.