Experts reveal the complexity of dermatitis management

Although the variety of substances that can cause contact dermatitis is almost limitless, it often can be effectively managed with the proper diagnosis and treatment according to investigators presenting the latest research at the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in Seattle.

Contact dermatitis is an acute or chronic inflammation of the skin resulting from interaction with a chemical, biologic or physical agent. It can cause much discomfort, have an impact on quality of life, and occasionally cause serious complications. Dermatitis can be widespread, or may be regional and restricted to a certain area of the body.

There are two basic types of contact dermatitis – irritant and allergic – but what they generally have in common is that they are caused by a reaction to specific allergens. The more common culprits include cosmetics, perfumes, certain foods, some metals, cleaning solutions, the metal nickel (found in jewelry and belt buckles), detergents, industrial chemicals, and latex rubber.

The face and eyelids are one of the most common sites for dermatitis to erupt, second only to the hands, explained Vincent A. DeLeo, M.D., chairman of dermatology at St. Lukes-Roosevelt and Beth Israel Medical Center in New York.

"It is probably even more prevalent than we suspect, since many people self-treat it without ever seeing a physician."

An eruption on the face and eyelids can be caused by a number of underlying factors, but is most commonly a reaction to a cosmetic, soap, or other personal care product. In fact, allergic dermatitis is due to an ingredient found in cosmetics in over half of all cases that undergo patch testing.

"The patient has often switched to a new brand of make-up or a different cleanser right before the skin outbreak occurred," said Dr. DeLeo. "We will usually treat the condition with a topical corticosteroid and have the patient stop using the product."

Patch testing is usually not necessary. It may be warranted if the patient continues to have flare-ups, despite topical treatment and changing skin care products, to confirm a diagnosis of allergic contact dermatitis.

Aside from personal care products, the array of substances that can cause face and eyelid dermatitis is daunting, ranging from medications to dust mites to plants. While most cases do respond to topical treatment, systemic therapy may be necessary for some patients.

In diagnosing contact dermatitis, it is important to remember that many patients will have multi-factorial disease, said Dr. DeLeo. Patients should be informed early in the process that, even if a positive patch test reveals relevant allergens, and even if they avoid those allergens, their dermatitis will improve, but may not completely clear.

Too much sun exposure can damage the skin, leading to premature aging or even malignant lesions. But for some individuals, exposure to the sun can precipitate an allergic reaction called photodermatosis. The most common form is called polymorphous light (PML) eruption.

"In lay terms, it is known as sun poisoning," said Dr. DeLeo.

"It affects about 10 to 15 percent of individuals living in the United States."

The cause of PML eruption is idiopathic in most cases, and some patients may not associate their skin complaint with exposure to light. "Most individuals only have one episode, and there is usually no obvious cause for suddenly becoming photosensitive," explained Dr. DeLeo.

 "After it clears, they can resume normal outdoor activities. They do not become more sensitive to sunlight."

In some cases, other types of photodermatosis can be precipitated by certain medications, an underlying medical condition, or by topical exposure to certain plants or chemicals. Photosensitivity can be confirmed by phototests, in which artificial light from various different sources is shone on small areas of the skin to see if the eruption can be reproduced. Patch testing and the combination photopatch can also be utilized if there is difficulty making an accurate diagnosis.

For most patients, the episode is short lived and will clear up on its own. "But since it can be very uncomfortable, we usually prescribed a topical corticosteroid," said Dr. DeLeo.

"A systemic steroid may be needed, but only when symptoms are more severe."

Hand dermatitis, or hand eczema, is one of the most common conditions seen by physicians in all specialties. In fact, about 20 to 35 percent of all dermatitis affects the hands, including more than 75 percent of work-related contact dermatitis. Foot dermatitis is less common and may occur alone or in conjunction with hand eczema. In severe cases, hand and foot dermatitis can have a significant negative impact on quality of life and cause considerable impairment and disability.

Irritant contact dermatitis is the most common cause of hand dermatitis in which people may notice dry, chapped hands that later become patchy, red and scaly. Numerous items can irritate the skin, especially over exposure to soap and water, solvents and cleaning agents.

"Allergic contact dermatitis of the hands is very common among certain occupations," said James S. Taylor, M.D., who directs the Section of Industrial Dermatology at the Cleveland Clinic in Ohio.

"This includes healthcare professionals, hairdressers and cosmetologists, woodworkers, machinists, and chemical workers."

A diagnosis is generally made employing a "diagnostic triad." This consists of taking a detailed patient history, evaluating the clinical presentation, and performing allergy patch tests. Common contact allergens include nickel, rubber components of gloves, preservatives, certain topical medications and personal care products and cosmetics.

Shoes are one of the most common culprits in causing foot dermatitis. In particular, the rubber accelerators found in shoes, dyes in leather and socks, and dichromates used in tanning leather can all cause an allergic reaction.

Patch testing is an important procedure in many cases of both hand and foot dermatitis since allergic contact dermatitis may occur alone or in conjunction with irritant, atopic or other forms of dermatitis. Treatment will depend on the cause of the dermatitis, said Dr. Taylor. "For allergic contact dermatitis, it involves allergen omission or substitution and generally using topical or occasionally systemic corticosteroids to relieve the symptoms."

New and innovative technology has allowed for a dramatic increase in the development of implanted medical devices. However, will placing stents, pacemakers and other devices into patients with allergies to metal put them at risk for a reaction?

That is a complicated question, according to Dr. Taylor. "We first have to know the composition of the device in question, and then if the patient is really allergic to it. If so, then is it a problem, and then what advice do we give to the consulting physician?"

Localized cutaneous and systemic reactions to implanted metals have been reported by a number of sources. However, most individuals – including patients who are sensitive to nickel – will tolerate low levels of the metal in tissue, such as with orthopedic prostheses.

"There is evidence that gold allergy was induced in some patients with gold-containing endovascular coronary stents and gold allergic patients had a higher incidence of in-stent restenosis (a recurrence of constriction after corrective surgery)," said Dr. Taylor.

"There is also a trend toward the occurrence of in-stent restenosis in nickel allergic patients."

"More patients and physicians are raising the issue of putative reactions to various implants in metal allergic patients. Right now routine pre-operative screening is not recommended, but we do have to evaluate patients and pay attention to reactions that may be related to the implant," he said.

Further prospective studies of these putative reactions are needed.

(Source: The American College of Allergy, Asthma and Immunology: November 2008.)