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
