IRRITANT CONTACT
DERMATITIS
Irritant contact dermatitis is one of the most commonly encountered
dermatoses in the dermatology clinic. Its true incidence is unknown. Irritant
contact dermatitis can be caused by a multitude of factors, and the morphology
of its appearance can be varied. One of the most common forms of irritant
contact dermatitis is seen on the hands and is caused by occupational exposures
to irritant chemicals or excessive hand washing.
Clinical Findings: Irritant contact dermatitis can occur at any
age. Some studies show that women are more commonly affected. There is no
racial predilection. There are many exposures that can eventually lead to the
development of irritant contact dermatitis. The final clinical manifestations
are similar despite the different instigating chemicals. Variations exist in
the location of the dermatitis. The hallmark of irritant contact dermatitis is
xerosis. Once the skin dries out to a certain point, it becomes inflamed. This
leads to the clinical picture of dry pink or red patches. On the hands, painful
fissures or splits may occur within the skin lines. Diaper dermatitis in
infants is one specific form of irritant contact dermatitis. The wet diaper
rubbing against the child’s buttocks and legs can cause skin irritation, red
patches, and occasionally erosions. The child can become irritable with
pruritus and is at higher risk for secondary bacterial infections.
Many chemicals are direct irritants
to the skin, and injuries from these agents are occasionally seen in a
dermatologist’s office. Exposure of the skin to hydro- chloric acid results in
skin cell death, necrosis, and inflammation. This, in turn, leads to the
development of red patches or plaques with varying amounts of erosion and
ulceration. These patients often receive care in an occupational work setting
or in the emergency room. The same can be said for exposure of the skin to
strong basic chemicals such as sodium hydroxide. Basic chemicals can cause an
irritant contact dermatitis that is directly related to the necrotic effect of
the chemical on the skin surface.
One of the most common causes of
irritant contact dermatitis is frequent hand washing. The use of soaps removes
the natural oils and waxes that the skin pro- duces as a way of physiologically
keeping the skin from drying out. Once the removal of these oils outweighs
their production, dryness begins to set in. If the skin is not given enough
time to repair itself, the epidermis continues to dry out and becomes inflamed.
Pink to red patches are evident, and, as the irritation continues, the dryness
worsens until fissuring and cracking occur.
Ring dermatitis is another common
form of irritant contact dermatitis. It is believed that soap residue builds up
between the surface of the ring and the skin. This prolonged contact causes an
irritant contact dermatitis underlying the ring. It can be misdiagnosed as an
allergic contact dermatitis, and on initial presentation, these two forms of
dermatitis cannot be differentiated. The main differential diagnosis is between
an irritant and an allergic contact dermatitis. The two have similar clinical
appearances and can be almost impossible to differentiate. Irritant contact
dermatitis typically has an acute onset and a decrescendo resolution, unless
there is repeated exposure to the irritant. Allergic contact dermatitis usually
has a crescendo-decrescendo clinical course. These patterns can be helpful in
differentiating the two conditions.
Pathogenesis: Exposure to an irritant chemical, whether an
acid or a base, or repeated exposure to soap and water leads to a
similar inflammatory cascade. The damaged keratinocytes release myriad
inflammatory cytokines. The intensity of the reaction is based on the
concentration of the irritant and the exposure time. The recruitment of T cells
occurs later in the time course of irritant contact dermatitis, when compared
with allergic contact dermatitus.
Treatment: The goal of treatment is to remove the skin from
exposure to the irritant. Barrier creams and frequent diaper changes may
be all that is needed to resolve irritant contact diaper dermatitis. Hand
dermatitis can be treated with a combination of moisturizers, topical
corticosteroids, and avoidance of frequent hand washing. If these changes can
be accomplished, the prognosis is excellent. Workers with potential
occupational exposures to irritant chemicals must be properly trained in
handling them and given the correct protective gear to prevent exposure.
