What is Pruritus?

Pruritus is the medical term for itching. It is an uncomfortable sensation that leads to a desire to scratch the affected area. Pruritus can occur on any part of the body and may be caused by various factors, including skin conditions, allergies, infections, medications, or underlying health issues. It can range from mild to severe and can significantly impact a person’s quality of life.

Types of Pruritus

Pruritus can be classified into various types based on different criteria. Here are some common types:

1. Localized Pruritus: Itching is limited to a specific area of the body. (scalp, genital area, or anus)

2. Generalized Pruritus: Itching affects multiple areas of the body. ( Ichthyosis vulgaris)
3. Acute Pruritus: Itching that develops suddenly and lasts for a short duration, often due to insect bites, allergic reactions, or contact with irritants.

4. Chronic Pruritus: Persistent itching lasting for six weeks or longer. Underlying.medical conditions such as eczema, psoriasis, liver or kidney disease, or neuropathic conditions.

5. Pruritus Noci: This type of itching is associated with a stimulus that directly activates the nerve fibres responsible for transmitting the itch sensation, such as insect bites or allergic reactions.

6. Neuropathic Pruritus: Itching caused by damage or dysfunction of the nervous system, leading to abnormal sensations on the skin.

Causes of Pruritus

• Skin Conditions: Various skin disorders can lead to itching, including dermatitis (such as eczema or contact dermatitis), psoriasis, fungal infections (like ringworm), and insect bites.
• Allergic Reactions: Allergies to substances like pollen, animal dander, certain foods, or medications can cause itching as part of the allergic response.
• Dry Skin: Skin that lacks moisture can become dry and itchy, especially in cold or dry climates or with frequent bathing.
• Systemic Diseases: Certain systemic conditions can cause itching such as , kidney disease, thyroid disorders, diabetes.
• Neurological Conditions: Disorders affecting the nervous system, such as neuropathy or multiple sclerosis, can cause neuropathic itching.
• Medications: Some medications can cause itching as a side effect.(opioids, certain. antibiotics, antifungal drugs, and medications used in cancer treatment)
• Psychological Factors: Stress, anxiety, and other emotional factors.
• Infections: Infections caused by bacteria, viruses, or parasites can lead to itching. (chickenpox, Herpes,, HIV/AIDS, and pinworms)
• Hormonal Changes: Hormonal fluctuations during pregnancy, menopause.
• Environmental Factors: Exposure to irritants such as harsh chemicals, soaps, detergents, or wool clothing can lead to itching.

What is Atopic Dermatitis?

Atopic dermatitis, often referred to as eczema, is an inflammatory skin condition characterised by dry, itchy, and red skin.

Skin Barrier Dysfunction: At the core of atopic dermatitis is a compromised skin barrier. The skin’s outermost layer, the stratum corneum, normally acts as a protective barrier, preventing water loss and blocking the entry of irritants, allergens, and microbes. In atopic dermatitis, this barrier function is impaired, leading to increased transepidermal water loss and susceptibility to environmental triggers.

Causes of Atopic Dermatitis

• Impaired skin barrier
• Stress
• Genetic factors
• Environmental triggers

How Atopic Dermatitis Occurs

Symptoms of Atopic Dermatitis

1. Oozing
2. Redness,
3. Itchiness
4. Inflammation
5. Dry skin

Management of Atopic Dermatitis

1. Anti itch medications
2. Topical Corticosteroids:
3. Topical Calcineurin Inhibitors:
4. Topical Phosphodiesterase-4 (PDE4) Inhibitors:
5. Antihistamines

Itch is associated with Atopic dermatitis

The pathogenesis of atopic dermatitis involves a complex interplay of genetic, environmental, immunological, and neurosensory factors.

1. Itch Sensitization: Dry skin in atopic dermatitis is associated with a lowering of the itch threshold, making the skin more sensitive to itch-inducing stimuli. Interleukin-33 (IL-33), produced by keratinocytes in response to skin damage or inflammation, plays a crucial role in sensitizing sensory nerve fibres, leading to heightened itch perception. Increased intraepidermal nerve fibres further contribute to itch sensitivity.

2. Itch-Scratch Cycle: The intense itching experienced by individuals with atopic dermatitis triggers scratching, which further damages the already compromised skin barrier. This scratching exacerbates inflammation and perpetuates the itch-scratch cycle. Additionally, the mechanical and chemical stimuli from scratching can activate sensory nerves, amplifying the perception of itchiness.

4. Type 2 Inflammatory Response: Disruption of the skin barrier allows entry of external substances, such as allergens from dust mites, which trigger an immune response dominated by type 2 cytokines, including IL-4, IL-13, and IL-31. These cytokines promote inflammation and further sensitize sensory nerve fibres, perpetuating the cycle of itch and inflammation.
5. Vicious Cycle: The itch-scratch cycle combined with ongoing inflammation forms a negative spiral, leading to a persistent and worsening disease burden. Chronic scratching and inflammation can result in thickened, lichenified skin, increased risk of skin infections, and significant impairment of quality of life
   
   

POINTS TO PONDER

• Histamine, released mainly by mast cells, is a well-known pruritogen involved in acute itch. However, intractable itch in AD is largely mediated by histamine-independent pathways.

• Various pruritogens beyond histamine, including proteases, cytokines (such as IL-31, TSLP, IL-4, and IL-13), neuropeptides (e.g., substance P, CGRP), lipids (e.g., prostanoids, leukotrienes), and opioids (e.g., β-endorphin, dynorphins), activate specific receptors on sensory neurons to induce itch.

• Cutaneous nerve fibres play a crucial role in transmitting itch signals, and their increased density contributes to heightened itch sensitivity in AD.

• Dry skin is a key feature of intractable itch in AD, leading to the release of endogenous mediators and dysregulation of antimicrobial peptides, further exacerbating itch and inflammation.
• Therapeutic strategies for managing itch in AD include targeting specific receptors or signalling pathways involved in itch sensation, modulating nerve fibre density, addressing skin dryness, and restoring the expression of antimicrobial peptides to improve barrier function and reduce inflammation.
  
  

Our product helps in providing relief from Itch due to Atopic Dermatitis

Adril Max Lotion

Composition:

1. Camphor- Cooling effect
2. Menthol – Cooling effect
3. Pramoxine hydrochloride- Antipruritic agent and local anaesthetic.

Mode of action of Pramoxine Hydrochloride :

Small unmyelinated C fibres are involved in the transfer of temperature, pain and itch from the periphery to synapse. The Pramoxine hydrochloride being a mild local anaesthetic acts as an antagonist for the sodium ions, and prevents the binding of sodium ions on the voltage gated sodium channels present on C fibres that results in stabilisation of the membrane thereby terminates the propagation of the action potential to adjacent neuron and hence there is no sensation of itch or pain.

For harsh pruritus associated with Atopic Dermatitis use Adril Max Lotion . A steroid free lotion formulated with Camphor & Menthol that gives a cooling effect and Pramoxine Hydrochloride that provides relief in 12 hrs after application.

Salient Features

• Non steroidal
• Prevent Excoriation.
• Provides long term relief.

What is Papular urticaria ?

Papular urticaria is an allergic skin reaction that typically results from insect bites. Itchy bumps often appear on uncovered areas of the skin, such as the face, forearms, and legs.

Types of Insect bites

4. Mosquito Bites: Raised, itchy bumps, often red or pink with a central puncture mark, causing mild to moderate itching and discomfort.
5. Bed Bug Bites: Small, red, itchy bumps clustered together in lines or zigzag patterns, may become inflamed and swollen, leading to secondary infections.
6. Flea Bites: Small, red bumps with a red halo, extremely itchy, often appearing in clusters or lines, especially on the legs and ankles.
7. Ant Bites/Stings: Red, swollen bumps, painful or itchy, fire ant bites may blister and be especially painful and itchy.
8. Bee and Wasp Stings: Immediate pain, swelling, redness, and itching at the site; allergic reactions can lead to difficulty breathing, hives, or swelling of the face and throat.

Symptoms of papular urticaria

(1)Bumps that are itchy, inflamed, raised

(2)Itch caused by Insect bites

Insect bites can trigger localized itching, particularly if the individual has an allergic reaction to components in the insect’s saliva or venom. Here is how allergic itch in localized insect bites typically occurs:

Introduction of Allergens:

When an insect bites, it injects saliva or venom into the skin. This saliva contains proteins and other molecules that can act as allergens in susceptible individuals. These allergens can trigger an immune response in the skin.

Activation of Mast Cells:

Mast cells are immune cells found in the skin and other

tissues. They play a crucial role in allergic reactions. When allergens from insect saliva enter the skin, they can bind to specific receptors on mast cells, leading to their activation.

Release of Histamine and Other Mediators:

Activated mast cells release various mediators, including histamine, leukotrienes, prostaglandins, and cytokines.

Histamine, in particular, plays a central role in triggering itch and inflammation in allergic reactions.

Histamine-Mediated Itch:

Histamine acts on sensory nerve endings in the skin, stimulating nerve fibres known as C-fibres. This stimulation sends signals to the brain, resulting in the sensation of itch (pruritus). The release of histamine also causes blood vessels to dilate and become more permeable, leading to redness, swelling, and heat at the site of the insect bite.

Recruitment of Immune Cells:

In addition to histamine, other inflammatory mediators released by mast cells attract immune cells, such as eosinophils, neutrophils, and T cells, to the site of the insect bite. These cells contribute to the local inflammatory response, leading to further itching, redness, and swelling.

Delayed Hypersensitivity Reaction:

In some cases, localized insect bites can trigger a delayed hypersensitivity reaction, where the immune system reacts more strongly to the allergens in subsequent exposures. This can lead to a prolonged and more intense itching response, as well as the formation of papules, blisters, or hives at the bite site.

Treatments for papular urticaria include:

• Oral antihistamine medication
• Antiseptic cream to prevent secondary infection
• Steroid cream

What are Drug Side Reactions?

Drug side reactions, also known as adverse drug reactions (ADRs), are unintended and harmful reactions that occur after the administration of a medication.

Types of Drug-Side Reactions

Some common types of drug side reactions include:

1. Allergic Reactions: These can manifest as rashes, hives, itching, swelling, or even anaphylaxis, which is a severe and potentially life-threatening allergic reaction.
2. Gastrointestinal Reactions: Drugs can cause nausea, vomiting, diarrhoea, constipation, or abdominal pain.
3. Central Nervous System Effects: Some drugs may cause dizziness, drowsiness, headache, confusion, or mood changes.
4. Hematologic Reactions: Drugs may interfere with blood clotting or cause abnormalities in blood cell counts, leading to bleeding disorders or anaemia.
5. Skin Reactions: Drugs may cause photosensitivity, skin rash, or skin discolouration.

Symptoms of Drug side reactions

Allergic inflammation caused by drug side effects can manifest in various ways, including:

1. Skin rashes
2. Hives (urticaria)
3. Swelling (angioedema)
4. Respiratory symptoms (e.g., wheezing, shortness of breath)
5. Gastrointestinal disturbances (e.g., nausea, vomiting, diarrhoea)
6. Systemic reactions (e.g., anaphylaxis)

Drug side effects causing allergic inflammation

It involves an immune response triggered by the body’s reaction to a medication. Here how it generally occurs:

1. Introduction of the Drug: When a person takes a medication, whether orally, Topically, or by injection, the drug’s active ingredients are introduced into the body.
2. Immune Recognition: Sometimes, the body may identify the drug or one of its components as a foreign substance or allergen. This recognition can occur due to various factors, including the chemical structure of the drug or previous exposure to similar substances.
3. Activation of Immune Response: Upon recognition of the drug as a potential threat, the immune system mounts an allergic response. This response involves the production and release of immunoglobulin E (IgE) antibodies specific to the drug.
4. Release of Inflammatory Mediators: IgE antibodies bind to mast cells and basophils, triggering the release of inflammatory mediators such as histamine, leukotrienes, and cytokines.
5. Tissue Inflammation: The release of these inflammatory mediators leads to inflammation in various tissues and organs throughout the body, depending on the route of administration and distribution of the drug.