Overview:
Prurigo Nodularis, as the name suggests, is a chronic inflammatory (pruritic) nodular skin disease that comes across as hard, itchy bumps or nodules, typically affecting the arms or legs. The condition, however, is more than just an itch. It is commonly a clinical manifestation of an autoimmune condition called cholestatic hepatitis. While the disease can affect both sexes regardless of age, it is more prevalent in older adults. The mainstay of treatment for prurigo nodularis is relieving the continuous itch-scratch cycle. A primary benefit of exploring patient-centered clinical trials is access to newer treatment approaches for vulnerable skin conditions before they reach the market.
Continue reading the blog to know more about prurigo nodularis.
What Is Prurigo Nodularis?
Prurigo nodularis, a chronic skin condition is characterized by hard, itchy nodules or bumps on the skin. It ranges in color and size from pink to brown, typically 0.5-3 cm. Intense itching, a predominant hallmark of prurigo nodularis significantly worsens at night. The itch-scratch cycle lingers to a point the skin starts to bleed. Once the skin is scratched, newer nodules are triggered in an endless itch-scratch cycle.
Diagnostic Dilemma:
The diagnostic dilemma associated with prurigo nodularis amplifies in the presence of cutaneous mimickers. Some of the commonly identified mimickers are:
Pemphigoid Nodularis:
a rare form of pemphigoid, replicates symptoms similar to those experienced in prurigo nodularis. A biopsy test is indicated to distinguish the conditions.
Hypertrophic lichen planus:
is another skin disease that typically produces lesions on sites similar to those influenced by prurigo nodularis. To discern between the two conditions, a dermoscopy test performs better.
Epidermolysis bullosa:
a rare subtype of epidermolysis bullous is associated with traumatic blisters. In a few circumstances, it is mistaken for prurigo nodularis because of the incidence on similar affected sites.
Etiology Of Prurigo Nodularis:
Understanding why itchy skin develops is complicated. Prurigo nodularis is a disease of multifactorial origin. While the exact cause of prurigo nodularis is not well understood, it is believed to be metastasized by chronic itching and scratching. In addition, stress acts as a potential risk factor for the exacerbation of prurigo nodularis. It is because prolonged periods of stress aggravate the itching and scratching associated with prurigo nodularis. Moreover; certain demographics and underlying conditions, from internal malignancy to renal failure to psychiatric conditions, contribute to the production of pruritic nodules.
Put simply, several factors contribute to the development of hard, itchy nodules on the skin.
The commonly identified causative factors for unwanted pruritic flares are:
- Atopic dermatitis
- Contact dermatitis
- Diabetes
- End-stage kidney disease
- Hepatitis C
- Untreated HIV
- Lymphoma (Hodgkin’s lymphoma, non-Hodgkin’s lymphoma)
- Mental health conditions, including anxiety or depression
Alongside the above-mentioned long-term medical conditions that contribute to prurigo nodularis, according to statistics:
- In about 50% of the cases, innate or acquired inflammatory conditions such as asthma, eczema, hay fever, and hives are identified as culprits for pruritic skin nodules.
- In other instances, 30% of the metabolic and chemical conditions such as uremia, an anomaly of the liver, and a nutrition deficit contribute to the itching associated with prurigo nodularis.
According to research, some people are at higher risk of developing prurigo nodularis:
- Older adults, greater than 50 years old
- Black people, with itchy skin conditions such as Atopic dermatitis, allergies, etc
- Certain chronic conditions
In the presence of a variety of circumstances, it is difficult to identify the sole reason behind the advent of the inflammatory response associated with prurigo nodularis.
To simplify the complexity, studies suggest that the condition may be the result of any of the following:
- An intense inflammatory response of the body
- Thickened excitable nerves due to scratching
- Changes in the person’s immune system
Clinical Presentation Of Prurigo Nodularis:
A typical presentation of the nodules produced in prurigo nodularis usually initiates as small, red, itchy papules or rounded skin bumps. As the condition advances, these rounded lesions evolve into large, dome-shaped, wart-like growth (nodules) up to 3 cm in diameter, firm to touch.
Additionally, as the nodules age, undergo a color change from red to brown-back to turning pale occasionally.
The condition manifests a wide range of clinical pictures depending on its severity and correspondence with other health conditions. The commonly reported features indicative of prurigo nodularis are:
Nodules:
Hard, raised bumps or nodules that are typically 0.5-3 cm in size and range in color from pink to brown.
Itching:
Pruritus, or intense itching, is a characteristic hallmark symptom of prurigo nodularis and can be exacerbated by heat, sweating, or emotional stress.
Scratching:
The nodules often develop as a result of chronic scratching or rubbing of the affected area. The reason behind this is the drying effect, which aggravates scratching, causes new nodules to form secondary to scratching and rubbing. This, leads to a cycle of itching, scratching, and more itching, which worsens the condition over time.
Localization:
The nodules are typically localized to one or more areas of the body, such as the arms, legs, back, or scalp.
Secondary changes:
Due to the persistent scratching, prurigo nodularis can cause secondary changes such as hyperpigmentation, scarring, and lichenification (thickened, leathery skin).
Discomfort:
The nodules can be uncomfortable or painful, especially if they become infected or inflamed.
Mentioned above are some of the commonly experienced symptoms of skin conditions similar to those experienced with prurigo nodularis. However, the distinctive “butterfly pattern” makes it stand out amongst other skin conditions. Dome-shaped nodular lesions following a typical distribution on the extensor surfaces of the extremities may be present elsewhere on the body, but the upper, and middle back, where the patient cannot easily reach, are typically spared. The resulting pattern of involved and clear skin is a classic “butterfly sign”, which is self-descriptive for prurigo nodularis.
Treatment Intervention:
It is important to note that treatment for prurigo nodularis may require a combination of therapies and may take some time to see improvement. Therefore, any treatment plan with the primary goal of treating the itch and preventing newer nodules from forming to allow the skin to heal should be considered.
Examples of standard medications available to relieve symptoms include
Topical corticosteroids:
are the most commonly prescribed ointment or cream for soothing prurigo nodularis. Topical corticosteroids reduce inflammation and itching and are applied directly to the affected skin.
Topical calcineurin inhibitors:
Tacrolimus and pimecrolimus are prescribed to reduce itching and scratching.
Oral antihistamines:
To reduce itching, cetirizine, fexofenadine, and loratadine, are consumed.
Phototherapy:
Light therapy is a treatment that involves exposing the affected skin to controlled amounts of natural or artificial light. It helps reduce inflammation and itching.
Systemic therapies:
These include oral corticosteroids, immunosuppressive agents, and other medications that can be taken orally or by injection.
Outlook:
Prurigo nodularis can be tough to deal with. The frequent itch and painful rash can take an emotional toll on people’s lives, making them vulnerable to a lack of confidence. Therefore, it is essential to consult with a dermatologist for a proper diagnosis and treatment if symptoms persist.
Moreover, self-care is essential, and getting psychological help can be beneficial. For additive care, multiple clinical research organizations are investigating new treatments for prurigo nodularis to help better manage the condition.