**Abstract**

Cupping therapy is an ancient method which has been used for centuries for various painful conditions. It is performed by applying cups to selected skin points most commonly in the back aiming to create areas of sub-atmospheric pressure. It has been classified as either dry or wet type of therapy. Its mechanism of action is not well understood but several proposed mechanisms are described in the literature. It is relatively safe with a few reported side effects which include scar formation and skin infection. In this paper, a review of the literature will be presented to determine its potential benefits in pain management particularly in musculoskeletal conditions such as low back and neck pain.

**Keywords:** cupping therapy, chronic pain, complimentary therapies, low back pain, pain management

## **1. Introduction**

Cupping therapy is one of the oldest methods of complimentary therapies which has been used in early human civilization. Evidence shows that it was first practiced by the Ancient Egyptians more than 5500 years ago and then it was introduced to the Greek, the Romans, and the rest of the world [1]. The main postulated aim of this therapy is the extraction of harmful substances or toxins from the body by creating negative pressure in a cup [2]. Cupping was described by Razi as a process in which blood from superficial small vessels located in muscles is released [3]. It has been traditionally used for the treatment of painful conditions but has also been used to treat chronic diseases such as cardiovascular disorders, skin diseases, inflammatory disorders, and metabolic diseases [4, 5]. Its exact mechanism of action is not well-understood but several theories have been proposed [6].

#### **2. Description of cupping therapy**

Cupping therapy is done by applying small round cups which are made of glass, bamboo, ceramic or plastic to the area of pain. The cup has a rolled rim to ensure tight contact with skin to preserve the negative pressure created [7]. The mouth of the cup is placed firmly over the preferred location against the skin. The negative pressure is generated by heat or by other vacuums like manual pumps. This negative pressure fixes the cup onto the skin and creates suction effect which pulls the skin upwards into the

cup. Sometimes, the therapist uses lubricants to facilitate the movement of the cups to cover a wider area [8]. The common application sites are the back, chest, abdomen, buttock, and areas of abundant muscle. Traditionally, the cupping therapy is done in sets of four, six or ten [9]. The cups are usually kept in place for 5 to 20 minutes [6]. The common side-effects of cupping therapy are erythema, edema, and ecchymosis in the area where the cup rim was placed. These effects may take several days to weeks to disappear [4, 10]. The cupping therapy process usually consists of the following five main steps:


#### **3. Mechanism of action**

While the exact mechanism of action of cupping therapy is not well-understood, multiple theories have been proposed. Six mechanisms of action have been suggested to describe the various effects of cupping therapy. Three of these theories are addressing the biological and mechanical basis of pain relief which results from cupping therapy. These theories are as follows: the pain-gate, the conditioned pain modulation, and the reflex zone. The remaining three proposed mechanisms of action are meant to explain the beneficial effects of cupping therapy which include an increase in blood circulation, immunomodulatory effects, and the removal of toxins and wastes [6]. The former three theories which are related to pain relief will only be discussed here.

#### **3.1 Pain-gate theory**

This theory proposes that cupping therapy could reduce pain intensity by influencing the communication routes of pain transmission from a stimulated area to the brain and backward [4]. Following a painful stimulus, pain signals are carried by both the small-diameter (A-delta and C) and the large-diameter (A-beta) nociceptive nerve fibers to synapse into a transmission cell in the dorsal horn of the spinal cord [12]. In this area pain modulation takes place through a network of interneurons and presynaptic pain gates [13]. The small fibers have an obstructive effect on the inhibitory cells thus allowing the flow of the transmission signals to the spino-thalamo-cortical pain pathway and then to the brain. While the large fibers stimulate the inhibitory cells and tend to inhibit transmission of pain signals. Thus, pain intensity is expected to be reduced when large nerve fibers are stimulated by touch or pressure or vibration. Based on this theory, both small and large nerve fibers are stimulated during cupping therapy [14]. During the initial stage of cupping therapy, the afferent large nerve fibers will partially close

**219**

*The Role of Cupping Therapy in Pain Management: A Literature Review*

the presynaptic gate as a result of the application of pressure to the skin [13]. As the stimulus intensity is increased, the number of activated units of nerve fiber increases. The subsequent positive and negative effects of the small and large nerve fibers responses tend to counteract each other. However, prolonged stimulation will lead to adaptation of the large fibers which will eventually result in opening of the presynaptic pain gates [13]. This adaptation can be modulated by employing additional stimuli during cupping therapy such as vibration and scratching to stimulate the large fibers again [15]. This increased activity will lead to the closure of the pain gates and experiencing further pain relief [15]. More research is needed to validate

This theory has been also known by the term "Diffuse Noxious Inhibitory Controls (DNICs)." It is based on the assumption that "pain inhibits pain," or one type of pain masks another [16]. DNIC comprises a spinal-medullary-spinal pathway that is activated when two concomitant painful stimuli are applied at the same time [16]. The activation of this pain pathway, which is triggered by a distant noxious stimulus, causes inhibition of the primary pain at the level of the nociceptive spinal neurons [16]. This pain inhibitory system has been successfully demonstrated in animal studies [17]. Furthermore, findings from clinical studies on the idiopathic pain syndromes such as irritable bowel syndrome, temporomandibular disorders, fibromyalgia, and tension-type headache had confirmed the relevance of this theory to chronic pain in humans [16]. According to this theory, local vibration or scratching done during cupping therapy causes a nociceptive stimulus that triggers the activation of DNICs which eventually lead to the relief of the primary pain [6].

Reflex Zone Theory proposes that there is an existing link between one organ of the body and another one. This link is mediated by interaction between nerves, chemicals, and muscles [18]. Thus, a disturbance in one organ causes external manifestations which can be detected at a site distal to the disturbed organ. The external manifestations are dependent on the organ manifesting them. For example, skin can become cold and pale due to vasoconstriction or it can become warm and red due to vasodilatation. The organ functions are affected due to a reduction in the circulating blood and tissue fluids [19]. Animal studies showed that somatic stimulation of the skin or the peripheral joints could lead to significant effects on the cardiovascular, urinary, and gastrointestinal functions [20]. These reflexes can be either excitatory or inhibitory in terms of organ function. Their main action is attained through spinal pathways, supra-spinal and cortical centers [20]. Therefore, it is hypothesized that the application of the cupping therapy cups over the skin result in the stimulation of the skin receptors which will eventually lead to an improvement in the blood circula-

Cupping was broadly classified into dry and wet cupping, but in 2016 Al-Bedah

*et al* introduced a new classification which consisted of six categories, namely, technical types, power of suction, method of suction, materials inside cups, area treated, and other cupping types [22]. Aboushanab *et al* made additional modifica-

tion through the neural connections to the affected organ [21].

**4. Classification of cupping therapy**

tions of these categories to become as follows [23]:

*DOI: http://dx.doi.org/10.5772/intechopen.93851*

the application of this theory in cupping therapy.

**3.2 Conditioned pain modulation**

**3.3 Reflex zone theory**

*The Role of Cupping Therapy in Pain Management: A Literature Review DOI: http://dx.doi.org/10.5772/intechopen.93851*

the presynaptic gate as a result of the application of pressure to the skin [13]. As the stimulus intensity is increased, the number of activated units of nerve fiber increases. The subsequent positive and negative effects of the small and large nerve fibers responses tend to counteract each other. However, prolonged stimulation will lead to adaptation of the large fibers which will eventually result in opening of the presynaptic pain gates [13]. This adaptation can be modulated by employing additional stimuli during cupping therapy such as vibration and scratching to stimulate the large fibers again [15]. This increased activity will lead to the closure of the pain gates and experiencing further pain relief [15]. More research is needed to validate the application of this theory in cupping therapy.

#### **3.2 Conditioned pain modulation**

*Pain Management - Practices, Novel Therapies and Bioactives*

main steps:

4.The cup is removed.

**3. Mechanism of action**

**3.1 Pain-gate theory**

cup. Sometimes, the therapist uses lubricants to facilitate the movement of the cups to cover a wider area [8]. The common application sites are the back, chest, abdomen, buttock, and areas of abundant muscle. Traditionally, the cupping therapy is done in sets of four, six or ten [9]. The cups are usually kept in place for 5 to 20 minutes [6]. The common side-effects of cupping therapy are erythema, edema, and ecchymosis in the area where the cup rim was placed. These effects may take several days to weeks to disappear [4, 10]. The cupping therapy process usually consists of the following five

1.The therapist assigns and disinfects the designated area for cupping therapy.

2.A suitable sized cup is positioned on the selected area and the therapist uses a method of suction to suck the air inside the cup. The cup will be left on the skin for 3–5 minutes. If it is wet cupping, then superficial incisions are performed on the skin by a scalpel blade (No. 15 to 21) or by puncturing the skin with a

5.The treated area is cleaned, disinfected, and a dressing is applied. The dressing

While the exact mechanism of action of cupping therapy is not well-understood, multiple theories have been proposed. Six mechanisms of action have been suggested to describe the various effects of cupping therapy. Three of these theories are addressing the biological and mechanical basis of pain relief which results from cupping therapy. These theories are as follows: the pain-gate, the conditioned pain modulation, and the reflex zone. The remaining three proposed mechanisms of action are meant to explain the beneficial effects of cupping therapy which include an increase in blood circulation, immunomodulatory effects, and the removal of toxins and wastes [6]. The former

needle, or an auto-lancing device or a plum-blossom needle [11].

is usually kept for 48 hours following the session of therapy [6].

three theories which are related to pain relief will only be discussed here.

This theory proposes that cupping therapy could reduce pain intensity by influencing the communication routes of pain transmission from a stimulated area to the brain and backward [4]. Following a painful stimulus, pain signals are carried by both the small-diameter (A-delta and C) and the large-diameter (A-beta) nociceptive nerve fibers to synapse into a transmission cell in the dorsal horn of the spinal cord [12]. In this area pain modulation takes place through a network of interneurons and presynaptic pain gates [13]. The small fibers have an obstructive effect on the inhibitory cells thus allowing the flow of the transmission signals to the spino-thalamo-cortical pain pathway and then to the brain. While the large fibers stimulate the inhibitory cells and tend to inhibit transmission of pain signals. Thus, pain intensity is expected to be reduced when large nerve fibers are stimulated by touch or pressure or vibration. Based on this theory, both small and large nerve fibers are stimulated during cupping therapy [14]. During the initial stage of cupping therapy, the afferent large nerve fibers will partially close

3.The cup is placed again on the skin for 3–5 minutes.

**218**

This theory has been also known by the term "Diffuse Noxious Inhibitory Controls (DNICs)." It is based on the assumption that "pain inhibits pain," or one type of pain masks another [16]. DNIC comprises a spinal-medullary-spinal pathway that is activated when two concomitant painful stimuli are applied at the same time [16]. The activation of this pain pathway, which is triggered by a distant noxious stimulus, causes inhibition of the primary pain at the level of the nociceptive spinal neurons [16]. This pain inhibitory system has been successfully demonstrated in animal studies [17]. Furthermore, findings from clinical studies on the idiopathic pain syndromes such as irritable bowel syndrome, temporomandibular disorders, fibromyalgia, and tension-type headache had confirmed the relevance of this theory to chronic pain in humans [16]. According to this theory, local vibration or scratching done during cupping therapy causes a nociceptive stimulus that triggers the activation of DNICs which eventually lead to the relief of the primary pain [6].

#### **3.3 Reflex zone theory**

Reflex Zone Theory proposes that there is an existing link between one organ of the body and another one. This link is mediated by interaction between nerves, chemicals, and muscles [18]. Thus, a disturbance in one organ causes external manifestations which can be detected at a site distal to the disturbed organ. The external manifestations are dependent on the organ manifesting them. For example, skin can become cold and pale due to vasoconstriction or it can become warm and red due to vasodilatation. The organ functions are affected due to a reduction in the circulating blood and tissue fluids [19]. Animal studies showed that somatic stimulation of the skin or the peripheral joints could lead to significant effects on the cardiovascular, urinary, and gastrointestinal functions [20]. These reflexes can be either excitatory or inhibitory in terms of organ function. Their main action is attained through spinal pathways, supra-spinal and cortical centers [20]. Therefore, it is hypothesized that the application of the cupping therapy cups over the skin result in the stimulation of the skin receptors which will eventually lead to an improvement in the blood circulation through the neural connections to the affected organ [21].

#### **4. Classification of cupping therapy**

Cupping was broadly classified into dry and wet cupping, but in 2016 Al-Bedah *et al* introduced a new classification which consisted of six categories, namely, technical types, power of suction, method of suction, materials inside cups, area treated, and other cupping types [22]. Aboushanab *et al* made additional modifications of these categories to become as follows [23]:
