Skin Care Education

Dermatitis

A broad term for skin inflammation causing redness, itching, and irritation. Covers several distinct conditions with different underlying causes, triggers, and patterns of behaviour.

What Is Dermatitis?

Dermatitis is a general medical term for inflammation of the skin. It describes a group of conditions that share the common feature of an inflammatory response in the skin, manifesting as some combination of redness, itching, swelling, scaling, crusting, or blistering. The term is broad and does not refer to a single specific condition but rather encompasses several distinct types that differ in their causes, their patterns of distribution on the body, and their clinical behaviour.

Dermatitis is not contagious and is not caused by poor hygiene. It is a common condition that affects people of all ages, skin types, and skin tones. Many forms of dermatitis are chronic, meaning they tend to persist over time and flare and settle in cycles rather than resolving with a single course of treatment. Others are acute reactions to a specific exposure and resolve once that exposure is removed.

In aesthetic and skincare contexts, dermatitis is relevant both as an underlying condition that affects how the skin tolerates products and professional treatments, and as something that certain skincare ingredients or inappropriate product use can trigger or worsen. Understanding which type of dermatitis is present is important for guiding appropriate skincare choices and professional treatment decisions.

Types of Dermatitis

Atopic dermatitis (eczema): the most common chronic form. Characterised by intensely itchy, dry, inflamed skin that tends to flare and settle in cycles. Strongly associated with genetic predisposition and commonly occurs alongside other atopic conditions such as asthma and hay fever. Most often begins in childhood but can persist into or begin in adulthood.
Contact dermatitis: caused by direct contact between the skin and an external substance. Divided into irritant contact dermatitis, a non-immune reaction caused by substances that physically damage the skin, and allergic contact dermatitis, an immune-mediated reaction to a specific allergen. Common triggers include fragrances, preservatives, metals such as nickel, and certain skincare or cosmetic ingredients.
Seborrhoeic dermatitis: causes scaly, flaky patches and redness in areas with high sebaceous gland activity, most commonly the sides of the nose, eyebrows, ears, and scalp. Associated with a naturally occurring skin yeast called Malassezia. Often chronic and requiring ongoing management.
Perioral dermatitis: a pattern of small red bumps and mild scaling around the mouth and sometimes the nose and eyes. More common in women. Frequently associated with prolonged use of topical corticosteroids and sometimes with fluorinated toothpastes or heavy occlusive moisturisers.
Nummular dermatitis: presents as coin-shaped patches of inflamed, itchy skin, most commonly on the limbs. Often associated with very dry skin and tends to worsen in cold, dry conditions.

Causes and Contributing Factors

Factor	Description
Compromised skin barrier	A weakened or disrupted outer skin barrier is a central factor in many forms of dermatitis, particularly atopic dermatitis. When the barrier is impaired, irritants and allergens penetrate more readily, and the skin loses moisture more rapidly, both of which increase inflammatory reactivity.
Genetic predisposition	Atopic dermatitis in particular has a strong hereditary component. Variants in genes responsible for barrier proteins, particularly filaggrin, are associated with increased susceptibility. A family history of atopic conditions significantly raises the likelihood of developing atopic dermatitis.
Immune system dysregulation	Both atopic and allergic contact dermatitis involve an overactive or misdirected immune response. In atopic dermatitis the innate immune system responds disproportionately to harmless stimuli. In allergic contact dermatitis the adaptive immune system becomes sensitised to a specific substance and mounts an inflammatory response upon re-exposure.
Exposure to irritants or allergens	Contact with substances that either directly damage the skin surface or trigger an allergic immune response is the primary cause of contact dermatitis. Common irritants include soaps, detergents, solvents, and water exposure. Common allergens include fragrance, nickel, cobalt, preservatives, and rubber chemicals.
Malassezia yeast	Seborrhoeic dermatitis is associated with an inflammatory response to Malassezia, a yeast that lives naturally on skin surfaces. Overgrowth or an atypical immune response to the yeast in sebum-rich areas of the face and scalp drives the characteristic scaling and redness.
Environmental triggers	Cold, dry weather, low humidity, excessive heat, sweating, and exposure to harsh environmental conditions can trigger or worsen flares across multiple types of dermatitis by disrupting the skin barrier and increasing inflammatory reactivity.
Stress	Psychological stress is a well-established trigger for flares of atopic dermatitis and can exacerbate other types. Stress hormones influence immune function and skin barrier integrity, contributing to increased inflammatory activity in susceptible individuals.
Topical corticosteroids	Prolonged or inappropriate use of topical corticosteroids around the mouth is one of the most commonly identified triggers of perioral dermatitis. Paradoxically, the condition often worsens temporarily when the steroids are discontinued before improving.

Frequently Asked Questions: Dermatitis

The terms eczema and atopic dermatitis are used interchangeably in clinical practice to refer to the same condition: the chronic, relapsing inflammatory skin condition associated with genetic barrier impairment and immune dysregulation. Dermatitis, however, is a broader umbrella term that encompasses several other distinct conditions including contact dermatitis, seborrhoeic dermatitis, and perioral dermatitis, none of which are referred to as eczema. All forms of eczema are dermatitis, but not all dermatitis is eczema.

No. All forms of dermatitis are inflammatory conditions arising from the interaction between the individual’s skin, immune system, and various triggers. None of them are caused by infectious agents and none can be transmitted from one person to another through contact. The red, scaly, or blistered appearance of dermatitis can sometimes be mistaken for an infectious condition, but it is important to understand that there is no risk of transmission.

Yes. Skincare and cosmetic products are among the most common triggers of contact dermatitis, both irritant and allergic. Fragrance is one of the most frequently identified allergens in cosmetic products. Other common culprits include preservatives such as methylisothiazolinone and parabens, certain emulsifiers, lanolin, propylene glycol, and botanical extracts. Products that are overly stripping or that compromise the skin barrier can also trigger or worsen atopic dermatitis in susceptible individuals.

Stress does not cause dermatitis in the sense of creating the underlying condition from scratch, but it is a well-established and clinically significant trigger for flares in those who already have a tendency toward inflammatory skin conditions. Stress influences immune function, increases systemic inflammation, and impairs skin barrier integrity, all of which can precipitate or worsen a flare of atopic dermatitis or other inflammatory skin conditions. Managing stress as part of an overall approach to skin health is therefore relevant, though it is rarely the only factor involved.