Dermatitis
Common skin inflammation with many forms.
Dermatitis is an umbrella term for several types of skin inflammation, most commonly marked by itching, redness, and a rash. When the condition is acute, small blisters may form; in chronic cases, the skin can thicken over time. The affected area may be tiny or cover the entire body. While dermatitis and eczema are often used interchangeably, "eczema" typically refers specifically to atopic dermatitis, the most prevalent form. The precise cause of dermatitis is frequently unclear, but it is thought to involve a mix of genetic and environmental factors. Cases may stem from a combination of allergic reactions and poor venous return. The specific type of dermatitis is usually identified by the patient's history and where the rash appears. For instance, irritant dermatitis commonly develops on the hands of people who frequently get them wet, while allergic contact dermatitis arises from exposure to an allergen, triggering a hypersensitivity reaction. Prevention of atopic dermatitis often involves essential fatty acids, and treatment includes moisturizers and steroid creams, which should be mid to high strength and used for under two weeks at a time to avoid side effects. Antibiotics are needed if a skin infection develops. Contact dermatitis is managed by avoiding the triggering irritant or allergen. Antihistamines can aid sleep and reduce nighttime scratching. Dermatitis affects a significant portion of the global population, with atopic dermatitis being the most common type, usually starting in childhood. Contact dermatitis is twice as common in females, and allergic contact dermatitis affects about 7% of people at some point. Irritant contact dermatitis is especially common in certain occupations.
Quick Facts
- Field
- Dermatology
- Complications
- Skin infection
- Causes
- Atopic dermatitis
- allergic contact dermatitis
- irritant contact dermatitis
- seborrhoeic dermatitis
- stasis dermatitis
- Diagnosis
- Based on symptom
- Differential
- Scabies
- psoriasis
- dermatitis herpetiformis
- lichen simplex chronicus
- Prevention
- Essential fatty acids
- Treatment
- Moisturizers
- steroid creams
- antihistamines
- Frequency
- 245 million in 2015 (3.34% of world population)
Facts from the source article.
Lore & Background
The exact cause of the condition is often unclear. Cases may involve a combination of allergy and poor venous return. The type of dermatitis is generally determined by the person's history and the location of the rash. For example, irritant dermatitis often occurs on the hands of those who frequently get them wet. Allergic contact dermatitis occurs upon exposure to an allergen, causing a hypersensitivity reaction in the skin. Dermatitis was estimated to affect 245 million people globally in 2015, or 3.34% of the world population. Atopic dermatitis is the most common type and generally starts in childhood. In the United States, it affects about 10–30% of people. Contact dermatitis is twice as common in females as in males. Allergic contact dermatitis affects about 7% of people at some point in their lives. Irritant contact dermatitis is common, especially among people with certain occupations, exact rates are unclear.
Reader's Guide
Dermatitis encompasses several distinct types of skin inflammation, including atopic, contact, stasis, and seborrhoeic forms, each with characteristic features. The primary symptom across all types is itchy skin, though irritant contact dermatitis tends to be more painful than itchy. Affected areas vary by type: atopic dermatitis commonly appears in the folds of the arms, behind the knees, on the wrists, face, and hands, while seborrhoeic dermatitis often begins as dandruff on the scalp and may spread to facial areas, the chest, and upper back. Dermatitis herpetiformis presents as small, red bumps about one centimeter in size, often grouped symmetrically on the back, buttocks, elbows, knees, neck, shoulders, and scalp, accompanied by itching, stinging, and burning. On lighter skin, dermatitis appears red; on darker skin, it may look darker brown or purple. The condition is not contagious, and its exact cause remains unclear, though a combination of genetic and environmental factors is suspected. The hygiene hypothesis suggests that an overly clean childhood environment may contribute to eczema by limiting exposure to bacteria and other immune modulators, with urban areas showing higher prevalence than rural ones. Complications include a risk of severe viral infections from smallpox vaccination, as well as recurring bacterial and viral infections due to deficiencies in skin barrier proteins and lipids. Daily moisturizing and anti-inflammatory therapy are recommended to prevent these infections.
Frequently Asked Questions
What is Dermatitis?
Dermatitis is an umbrella term covering several forms of skin inflammation that typically show up as itching, redness, and a visible rash. Rather than one single condition, it is a broad family of related skin reactions.
How is Dermatitis different from Eczema?
People often use the two words interchangeably, but 'eczema' is more precisely reserved for atopic dermatitis, the most frequently seen subtype. Dermatitis is the wider category, and eczema is one prominent member of that family.
How common is Dermatitis?
In the United States, atopic dermatitis is estimated to affect roughly 10–20% of children and about 1–3% of adults. For other subtypes like contact dermatitis, prevalence figures shift from study to study, and no single universally agreed-upon gender ratio has been established.
What are the main subtypes of Dermatitis?
The most widely recognized forms are atopic dermatitis (commonly called eczema) and contact dermatitis, which is triggered by the skin touching an irritant or allergen. Each subtype can differ in its triggers, how long it lasts, and the specific way the skin reacts.
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