Is Neurodermatitis an Autoimmune Disease? Causes & Triggers

Several factors may contribute to the development of neurodermatitis, include:

• Environmental factors such as skin irritants, tight clothing, or bug bite
• Systemic disorders such as psoriasis (chronic autoimmune disease that causes skin inflammation), eczema, and lichen planus (immune-mediated condition) 
• Psychological factors or diseases such as obsessive-compulsive disorder, anxiety, stress, and depression

It is speculated that some individuals have an inherited genetic predisposition, but the primary itch occurs as a result of certain skin conditions. The continuous cycle of scratching and itching can be triggered by external factors that may have irritated the skin.

Studies have reported that the condition is more common in people in the age group of 30-50 with a female predominance (at a ratio of 2:1).

The exact underlying cause of neurodermatitis is unknown. However, several studies have indicated that there may be some key triggers that can precipitate the condition:

• Extreme stress
• Anxiety
• Emotional trauma 
• Depression
• Obsessive-compulsive disorder
• Nerve injuries or hypersensitive nerves
• Insect bites
• Dryness of skin
• Wearing tight clothing, especially made up of synthetic fiber such as polyester or rayon
• Other skin diseases such as eczema, lichen planus and psoriasis

Anybody can develop neurodermatitis, but some people are more likely to get it than others. Risk factors include:

• Sex (women are more affected)
• Age (people between ages 30-50 are more affected)
• Other skin conditions such as contact dermatitis, atopic dermatitis (allergic skin conditions), and psoriasis (an autoimmune disease)
• Anxiety disorders and obsessive-compulsive disorders
• Family history of other skin diseases including eczema and contact dermatitis

Although not confirmed, some recent studies have suggested that those with certain personality traits, poor social skills, lack of flexibility, a tendency toward pain avoidance, dependency on other people, and people-pleasing may be more prone to developing neurodermatitis.

Neurodermatitis can occur anywhere on the body, mostly on the arms, shoulders, elbows, legs, ankles, wrists, hands, back of the neck, or scalp. Sometimes, the anal and genital areas and the face may also be affected.

The characteristic lesions of neurodermatitis are plaques measuring around 3 to 6 cm that appear:

• Dry
• Thick
• Scaly
• Leathery
• Discolored (reddish, brownish, yellowish, gray, or purple)

Older patches are white or pale in the center, surrounded by darker colors. Itching is intense, causing frequent scratching that makes the plaque lichenified (lichenification).

The chronic inflammation due to the pressure of the increased thickness of the cornified layer of the skin on the more fragile layers below leads to more itching, which causes even more scratching. This scratch-itch cycle is self-perpetuating, where the initial stimulus leads to scratching, which results in thickening of the skin, and eventually leads to more itching.

Itching is often more intense when you are relaxed or trying to sleep, often making you wake up in the middle of the night to scratch the affected area.

Neurodermatitis is usually diagnosed by a dermatologist after taking a medical history, examining the affected skin, and ruling out other skin conditions such as eczema and psoriasis. Tests that may be ordered include:

• Skin swab test: To find out if there is an infection
• Patch test: To confirm if an allergy is a problem
• Fungal tests: To identify skin disorders in the general and rule out sexually transmitted infections
• Skin biopsy: To find or rule out psoriasis or mycosis fungoides (a form of lymphoma)

Neurodermatitis is a non-life-threatening and lifelong condition, but the itching can be so intense that it significantly impacts quality of life.

With the right treatment plan and appropriate self-care, neurodermatitis can heal completely and has a good prognosis; however, neurodermatitis can relapse if activated by one of the triggers. 

In rare cases, neurodermatitis can develop into skin cancers such as squamous-cell or verrucous carcinoma, possibly due to continuous scratching and rubbing that activates chemicals causing inflammation, which in turn can transform the skin cells into cancerous cells.