Prurigo nodularis (PN), also known as nodular prurigo, is an inflammatory skin condition that causes intense itching, which leads to scratching and picking. This constant scratching causes hard, raised bumps (known as nodules or picker’s nodules) to form on the skin. These nodules then become itchy, causing the skin to break and potentially become infected.

PN may be associated with other systemic (affecting the entire body) medical conditions, such as:

• Atopic dermatitis (eczema)
• Bullous pemphigoid (causes skin blistering)
• Psoriasis
• Chronic kidney disease
• Thyroid problems
• HIV infection
• Cancer

Many of these medical conditions cause itchy skin as a symptom, which results in scratching and eventually leads to nodules and thickening of the skin.

Skin Symptoms of Prurigo Nodularis

Intense itching (known as pruritus) causes people with PN to excessively pick at and scratch their skin. In response to the scratching, the skin thickens, forming itchy bumps, nodules, and scarring.

PN can develop anywhere on the body where you pick at or scratch your skin. However, the bumps tend to appear in some areas more than others, including:

• Arms
• Upper or lower back
• Abdomen
• Legs
• Buttocks
• Back of the scalp

Picker’s nodules are less common in the middle of the back because it is more difficult to reach this area.

Intense Itching and Crawling Sensation

For many people with PN, rashes are brought on by intense itching, burning, or stinging sensations on the skin. In rare cases, people have reported feeling like bugs are crawling across their skin. These sensations may be caused by:

• Stress
• Insect bites
• Other skin conditions, such as eczema, lichen planus, or psoriasis
• Brachioradial pruritus, a nerve condition that causes itching and stinging on the forearms

Naturally, once your skin starts to itch, you may scratch it. In PN, this itching and scratching can cause hard bumps, or nodules, to form on the skin. These nodules may also itch intensely, leading to the itch-scratch cycle. Dermatologists often choose treatment options that focus on breaking this cycle to stop more nodules from forming.

Papules, Nodules, or Plaques

Intense itching and picking can cause firm nodules to form on the skin. They typically appear around six weeks after an itching episode. The nodules may also itch after they form, either occasionally or continuously.

PN skin lesions can range in size from 0.2 inches (0.5 centimeter) up to 1.2 inches (about 3 centimeters). The term used for the lesions depends on their size and what layers of the skin they affect:

• Papules are typically less than about 0.4 inches (1 centimeter) long and are raised above the skin’s surface.
• Nodules are longer than 0.4 inches (1 centimeter) and affect multiple layers of skin, including the epidermis (top layer of skin) and the dermis (the next layer down from the epidermis).
• Plaques are also longer than 0.4 inches (1 centimeter), but they typically cover more of the outer skin layer and do not go as deep.

PN rashes and lesions tend to be symmetrical, meaning they appear on both sides of the body in the same place. Each person’s PN case is different, and the number of nodules varies from person to person. Some individuals may have only a few nodules, but others may have hundreds. They may also be different colors, ranging from the color of your skin to red, pink, black, or brown.

Thickened Skin and Scarring

Over time, the excessive scratching associated with PN can cause the skin to become thicker and scarred. This is called lichenification or hyperkeratosis because the skin begins making too much of the protein keratin in response to irritation. These thicker patches of skin may look like calluses.

PN nodules may last for months to years, depending on the severity of your condition. Even after the bumps recede and rashes go away, they can leave scars. You may notice darkened flat spots where nodules once were, scarring from itching, or lighter-colored spots on your skin.

Skin Infections

Secondary bacterial infections can also occur in people with PN. This is because itching and picking at the skin can cause open wounds, especially around nodules. As a result, bacteria can get into the open wound and grow. Infected nodules and other skin lesions may be red, swollen, painful to the touch, or appear crusted over. They can cause a person to have fever and are a potential source of severe infection.

Mental Health Symptoms of Prurigo Nodularis

Many skin disorders negatively affect mental health and the overall quality of life of those living with the conditions. Because skin conditions are often very visible, many people who have them feel stressed, anxious, and stigmatized. Some studies have investigated how living with PN affects mental health.

Depression, Anxiety, and Other Mental Health Conditions

Depression and anxiety are common in people living with skin disorders such as PN. One study found that out of 7,095 people with PN, 1,513 (21.3 percent) had anxiety. There were also 1,228 people (17.3 percent) living with mood disorders, which can include depression and bipolar disorder.

Constant itching and scratching may also make it difficult for you to carry out your daily activities, either from the constant itch or the lack of sleep at night caused by scratching. According to the American Academy of Dermatology, people with PN have reported that the condition interferes with going to work or school and prevents them from going out to social events or activities.

Insomnia

Many people with inflammatory skin diseases such as PN, psoriasis, and eczema have difficulty sleeping due to itchy skin. These skin conditions make it more difficult to regulate body temperature, hormonal levels, and inflammation during sleep, which leads to itching sensations. This is known as nocturnal pruritus and may lead to insomnia or other sleep disturbances. One study of 39 people with PN showed that 29 of the participants experienced sleep disturbances to a mild, moderate, and great extent.

Find Your Team

MyPrurigoTeam is the social network for people with prurigo nodularis and their loved ones. On MyPrurigoTeam, members from all over the world come together to ask questions, give advice, and share their experiences with others who understand life with prurigo nodularis.

Do you have prurigo nodularis? Share your experience in the comments below, or start a conversation by posting on your Activities page.