What are the other Names for this Condition? (Also known as/Synonyms)

• Nodular Prurigo
• Picker’s Nodules
• PN (Prurigo Nodularis)

What is Prurigo Nodularis? (Definition/Background Information)

• Prurigo Nodularis (PN) is a common and benign skin disorder that is characterized by the presence of often multiple, itchy, skin nodules that mostly occurs on the arms and legs
• The condition mostly affects young and middle-aged women. The cause of Prurigo Nodularis is unknown, but it may be influenced by factors such as stress, other skin conditions, and even kidney/liver dysfunction
• Prurigo Nodularis can lead to complications such as secondary skin infections due to bacteria or fungi. Some individuals may develop emotional and psychological stress due to cosmetic concerns
• Prurigo Nodularis can be treated through a combination of topical applications and oral medications, along with adequate skin care and personal hygiene
• Presently, it may not be possible to prevent Prurigo Nodularis. Nevertheless, the prognosis of this skin disorder is normally excellent with suitable treatment

Who gets Prurigo Nodularis? (Age and Sex Distribution)

• Prurigo Nodularis is seen in all age groups but typically observed in young and middle-aged adults
• Both male and female genders are affected, although a female predilection is observed
• Individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Prurigo Nodularis? (Predisposing Factors)

Following are the risk factors for Prurigo Nodularis:

• Emotional stress; anxiety and depression
• Skin conditions that include atopic dermatitis, irritant contact dermatitis, and psoriasis
• Liver disorders
• Linear IgA disease (a type of autoimmune disorder)
• Thyroid dysfunction
• Kidney failure
• Insect bites in children

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Prurigo Nodularis? (Etiology)

The cause of development of Prurigo Nodularis is not well known.

• Prurigo Nodularis is a type of neurodermatitis, which is any skin condition made worse  by emotional stress, anxiety, or depression
• It does not spread from one individual to another through physical contact or through sharing of items. It is a non-infectious condition

What are the Signs and Symptoms of Prurigo Nodularis?

The signs and symptoms of Prurigo Nodularis may include the following:

• The distinctive characteristic of Prurigo Nodularis is the presence of multiple papules and nodules (in most cases) that are itchy
• This can lead to chronic and continuous itching and scratching, which is a very prominent feature of this disorder
• The nodules are firm; each nodule may range in size from a few mm to a few cm
• Frequent ulceration of the nodules are known to occur
• The nodules are observed in areas that are within easy reach of scratching, such as on the arms, legs, head and neck area, and in the pelvic region
• The skin may break, causing oozing, or raw skin appearance from intense scratching
• Long-term scratching causes thick, leather-like skin (lichenification); there may be scales on the skin
• The condition can cause hyperpigmentation of skin in the affected area

How is Prurigo Nodularis Diagnosed?

A few diagnostic tests that are performed for Prurigo Nodularis may include:

• A thorough physical examination and evaluation of a complete medical history
• Dermoscopy: Dermoscopy is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Blood tests, to rule out other causes such as infections
• Potassium hydroxide (KOH) test: The KOH prep involves microscopic observation of skin scrapings for any fungal infections
• Allergy skin test
• Skin biopsy: A biopsy of the lesion is usually performed to confirm the diagnosis. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Note: A tissue biopsy of the skin nodules is generally not necessary, but may be performed to rule out other conditions or infections.

A differential diagnosis may be undertaken to eliminate the following conditions:

• Atopic dermatitis
• Fungal skin infections
• Irritant contact dermatitis
• Psoriasis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Prurigo Nodularis?

The complications of Prurigo Nodularis may include:

• The bleeding and ulceration of the skin lesions can cause fungal or bacterial infections to form on the skin surface
• Chronic and intense itching can cause permanent scarring of the skin
• Emotional and psychological stress due to cosmetic issues arising from the scaly, leathery skin
• Loss of sleep due to scratching at night

How is Prurigo Nodularis Treated?

The following measures may be used to treat Prurigo Nodularis:

• Taking proper skin care by avoiding the tendency to itch
• Avoiding activities that can aggravate the condition; avoiding harsh soaps and detergents
• Maintain cleanliness and body hygiene
• Using moisturizers or other lotions to prevent the skin from drying
• Use of topical corticosteroid creams and lotions
• Vitamin D and calcineurin inhibitor creams
• Administration of antihistamines, if itching is due to allergic causes and for direct anti-itch effects
• Antibiotics may be used to treat infections
• Use of occlusive bandages to prevent itching or scratching the skin surface
• Unna Boot: A roll of gauze, medicated with zinc oxide paste is wrapped around the large areas of thickened skin (particularly in the calf region). This is placed for up to 1 week, to prevent scratching and further deterioration of the condition
• Additionally, cryosurgery and phototherapy may be useful in treating the skin nodules
• Undertaking treatment of any underlying disorders or conditions
• Behavioral modification therapy and stress management
• Selective serotonin reuptake inhibitors (SSRI) and tricyclic antidepressants can be effective
• Other central acting agents are used in treatment resistant cases
• Nemolizumab has recently been FDA-approved for treatment of pruritis associated with Prurigo Nodularis

How can Prurigo Nodularis be Prevented?

Currently, it may not be possible to prevent Prurigo Nodularis. However, the following factors may help control severity of the symptoms and prevent worsening of the skin texture:

• Maintaining proper hygiene
• Keeping the skin moisturized
• Avoiding the tendency to itch
• In children, clipping the nails short can be particularly beneficial

What is the Prognosis of Prurigo Nodularis? (Outcomes/Resolutions)

The prognosis of Prurigo Nodularis is generally excellent with appropriate treatment.

Additional and Relevant Useful Information for Prurigo Nodularis:

There is no evidence to prove that dietary factors have an influence on Prurigo Nodularis.