Contact dermatitis: Diagnosing and treating skin conditions in the elderly

Contact dermatitis is a significant cause of skin disease in geriatric patients. We discuss factors that predispose older adults to contact dermatitis, such as changes in barrier function and types of commonly contacted irritants and allergens.

Dermatitis is a significant disease in the geriatric population. The 1996-1997 National Ambulatory Medical Care Survey showed that "Dermatitis, Not Otherwise Specified (NOS)" was the sixth most frequently coded dermatologic diagnosis for adults aged 55 and older. This diagnosis, from physicians in all specialties, accounted for approximately 840,000 visits per year.

Acute dermatitis typically presents as erythematous papules with weeping, oozing, and crusting. Subacute dermatitis usually has erythema and scaling. As the process becomes more chronic, the epidermis becomes thickened, or lichenified. The key symptom of dermatitis is pruritus. Histologically, dermatitis is characterized by spongiosis, an inflammatory reaction by T lymphocytes causing intercellular edema, which accentuates the appearance of intercellular bridges.

Clinically, contact dermatitis can be recognized by distinctive patterns, as well as by its distribution. A classic example is nickel dermatitis. A characteristic, well-defined eczematous plaque is seen under the patient's watch or near the umbilicus where the skin chronically contacts the nickel-containing fasteners of pants. Plant exposure gives rise to a linear pattern. Aerosolized allergens affect unprotected areas, whereas sensitivity to dyes or formaldehyde in clothing affects covered areas.

Differential diagnosis

The superficial inflammatory process known as dermatitis is categorized by chronicity of the condition as acute, subacute, or chronic. Contact dermatitis is further identified as either irritant or allergic, the distinction being based on immunologic mediation.

Irritant contact dermatitis (ICD) is a nonimmunologic response that does not require sensitization. In the general population, ICD accounts for approximately 80% of contact dermatitis. The diagnosis of ICD is easily made when potent irritants, such as an acid splash, cause symptoms within minutes of exposure. The diagnosis is considerably more difficult to make, however, when minor irritants cause subacute to chronic dermatitis such as that caused by frequent hand washing.

To help distinguish between ICD and allergic contact dermatitis (ACD), diagnostic criteria are divided into subjective and objective and further subdivided into major or minor criteria.

Subjective major criteria for ICD:

* Onset of symptoms within minutes to hours of exposure
* Symptoms of pain, burning, stinging, or discomfort exceeding itching, especially early in the clinical course.

Subjective minor criteria for ICD: