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DIFFERENT TYPES OF IRRITANT CONTACT DERMATITIS

Irritant Contact Dermatitis (ICD) is an inflammatory skin disease that is a major occupational health concern worldwide. Irritant contact dermatitis is involved in an estimated 70% to 80% of all occupational skin hazards reported. This has led to the term Occupational Irritant Dermatitis (OID) to define contact dermatitis that occurred as a result of exposure to irritants in the workplace. Irritant contact dermatitis grew in alarming proportions after the industrial revolution and is becoming increasingly prevalent in currently developing nations.

Irritant contact dermatitis is caused by the direct exposure of the skin to irritant agents and it has no immunological connection – there is no systemic immune response from the body involved. Irritant contact dermatitis must be differentiated from its close clinical counterpart allergic contact dermatitis (ACD), which is however related to an immunological disorder (the body’s immune system responds to an allergen).

Both these forms of contact dermatitis have very similar clinical features, histology (microscopic tissue study), and immunohistology, though they differ in their pathogeneses. For a correct prognosis, it is necessary not only to differentiate between allergic contact dermatitis and irritant contact dermatitis, but also to know about the clinical features of different types of irritant contact dermatitis. They are as follows:

Acute Irritant Contact Dermatitis

Acute irritant contact dermatitis is a common workplace hazard. It generally happens due to accidental contact with a strong irritant. Acute irritant contact dermatitis is marked by a characteristic ‘decrescendo’ syndrome. This involves a steady reactive climax (the time span can be anything from a few minutes to some hours) after exposure, followed by a healing process.

Clinical indications are:

  • Burning (chemical burns)
  • Stinging
  • Soreness of the exact inflamed location
  • Redness of the skin (erythema)
  • Excess fluid build up in tissue cells (edema)
  • Blisters (bullae)
  • Possible necrosis (destruction of tissues)

The acute lesions are localized (limited to the exact location of toxic damage of the tissue by contact with the irritant), have well-marked outlines and irregular distribution (that indicates an external cause). Common irritant agents are acids or alkalis.

Acute Delayed Irritant Contact Dermatitis

This kind of irritant contact dermatitis is a late inflammatory reaction that is detected frequently during patch testing.

It can be caused by the following irritants among others:

  • Anthralin (dithranol)
  • Benzalkonium chloride
  • Ethylene oxide

Clinical features are:

  • Inflammation noticeable only after 8 to 24 hours (or even more) after contact with the irritant.
  • It may have almost identical symptoms to allergic contact dermatitis. The differentiating factor can be a burning sensation that is exclusive to irritant contact dermatitis rather than itchiness (pruritus) that is specific to allergic contact dermatitis.
  • Susceptibility to touch and water are key indicators of ICD.

Irritant Reaction Irritant Contact Dermatitis

Irritant reaction irritant contact dermatitis is a sub clinical irritant dermatitis that occurs in workplaces with a wet chemical ambience. Types of workers at high risk to this kind of irritant contact dermatitis are:

  • Hairdressers
  • Caterers
  • Metal workers

In other patients this condition often begins at a spot covered and confined by jewelry and then spreads over the fingers, hands and the forearms.

Its clinical indications are:

  • Scaling
  • Redness (erythema)
  • Vesicles (water filled blisters)
  • Pustules
  • Erosions

Clinical complications are:

  • Dyshidrotic dermatitis
  • Cumulative irritant contact dermatitis, if contact is for a long span of time.

Cumulative Irritant Contact Dermatitis

Cumulative irritant contact dermatitis is caused by multiple sub-threshold skin abuse, with an array of triggers and repetitive attack of irritant agents. Moreover, the repeated skin abuse occurs at such a close interval that it does not allow enough time in between for total renewal of the affected skin barrier function. The condition is manifest only after the cumulative effect of the repetitive abuse reaches a clinical climax or limit, which may however reduce with the advancement of the disease.

Mild irritants generally do not cause irritant contact dermatitis, especially if exposure to them is at an interval that enables restoration of skin barrier function. However, they can pose a threat, if contact is at very close intervals or if the clinical limit is decreased. Cumulative irritant contact dermatitis is also influenced by the characteristics of the irritant, which include pH, solubility, detergent activity, physical condition etc.

Clinical indicators are:

  • The lesions are better defined in acute patients than in chronic patients.
  • Chronic patients also suffer from itching and pain.
  • Xerosis, erythema, vesicles are the lesser symptoms.
  • Lichenification and hyperkeratosis of the skin are major symptoms.

Asteatotic Dermatitis

Asteatotic dermatitis or ‘exsiccation eczematid irritant contact dermatitis’ occurs only in the dry winter weather. It often affects elderly people who take a bath without a proper moisturizing regime as aftercare. Less commonly it can affect younger people too.

Its clinical features are:

  • Severe itchiness.
  • Dry skin with ichthyosiform scaling.
  • Skin patches of eczema craquele.

Traumatic Irritant Contact Dermatitis

As the name suggests, Traumatic irritant contact dermatitis occurs as a result of intense skin trauma in the form of burns, deep gashes or cuts or severe irritant contact dermatitis. Use of strong soaps or detergents in skin damaged areas can also cause the associated trauma.

Clinical features include:

  • Long-term eczematous lesions mainly in the hands.
  • Slow healing spread over at least 6 weeks.
  • Reddening of the affected spot.
  • Infiltration of the affected area by inflammatory cells.
  • Scaling of the skin.
  • Fissuring of the skin.

Pustular and Acneiform Irritant Contact Dermatitis

Pustular and acneiform irritant contact dermatitis are commonly caused by the following irritants:

  • Metals
  • Croton oil
  • Mineral oils
  • Tars
  • Greases
  • Cutting and metal working associated chemical solutions
  • Naphthalenes

Clinical features can include:

  • Folliculitis or acneiform lesions, mainly in patients with atopic dermatitis, seborrhea, or previous acne vulgaris.
  • Unproductive and temporary eruptions.
  • Miliarial eruptions due to enclosing garments, adhesive tape and ultraviolet and infrared rays.

Non-erythematous Irritant Contact Dermatitis

Non-erythematous irritant contact dermatitis is a subclinical variant of irritant contact dermatitis. It is marked by early skin irritation phases noticed in the form of changes in the barrier function of the outermost layer of the skin (stratum corneum). However, this occurs without much clinical relevance.

Subjective or Sensory Irritant Contact Dermatitis

Subjective or sensory irritant contact dermatitis is caused by irritants like lactic or sorbic acid. Clinical features include:

  • Stinging sensations
  • Burning sensations
  • Lack of visible skin irritation

This reaction may be accurately ascertained with dose reactivity in double-blinded contact patch tests.

Airborne Irritant Contact Dermatitis

Airborne irritant contact dermatitis occurs in sensitive skin of the face and periorbital regions on exposure to irritants in the air. It is often identical in its clinical features with photoallergic reactions. It can be distinguished via its location of occurrence such as the upper eyelids, philtrum (the infranasal depression or the vertical passage in the upper lip) and in areas under the chin.

Frictional Irritant Contact Dermatitis

Frictional irritant contact dermatitis is a distinct irritant contact dermatitis subtype resulting from repeated substandard frictional trauma. It is also has a supplementary effect in allergic contact dermatitis and irritant contact dermatitis.

The clinical traits in the affected skin are:

  • Hyperkeratosis
  • Acanthosis
  • Lichenification
  • Hardening
  • Thickening
  • Greater roughness