Advances in Skin & Wound Care made the decision many years ago to add the word “skin” to the journal’s title to recognize that wound care providers do not just care for “holes” in the patient—they care for the whole patient. The December CE/CME accordingly highlights the importance of skin and the latest information about dermatitis specifically. The article explores the differences among the three most common types of dermatitis: atopic, irritant contact, and allergic contact.
Allergic contact dermatitis is very important to leg ulcer patients and our treatment of these individuals. Many topical creams, ointments, lotions, and gels contain potential allergens. Leg ulcers are often chronic, and the open skin of the ulcer base serves as an excellent vehicle for systemic absorption of topical agents. For these reasons, persons with leg ulcers have a very high incidence of allergic contact sensitization.
One common example is lanolin or wool wax alcohols. Lanolin is a weak sensitizer for most individuals but a moderate sensitizer for persons with atopy and a strong sensitizer in persons with leg ulcers. Other common local sensitization issues come from topical antimicrobial agents often included in double or triple antibiotic creams and ointments. These agents often need only one mutation for bacterial resistance, and they do not provide autolytic debridement or moisture management as part of local wound care with the wound bed preparation paradigm.
Topical applications will only treat local infection on the surface of the wound and not deep and surrounding infection that requires a systemic agent. Dressings with antimicrobial properties often provide moisture management, and calcium alginates, hydrogels, and hydrocolloids are common examples of dressings with additional autolytic debridement properties. These topical antiseptic dressings require several mutations for resistance and are less likely to be associated with allergic contact reactions.
Other common allergens identified in leg ulcer patients include fragrances, colophony, tincture of benzoin, and the adhesives in some hydrocolloid dressings. If a moisture management dressing cannot handle exudate and there is leakage or strikethrough, irritant contact dermatitis may develop. One form of irritant contact dermatitis is moisture-associated skin damage, which may be attributable to wound fluid leakage but is also associated with incontinence, sweating, or leakage from an ostomy appliance.
Allergic contact patch tests are conducted with the North American Contact Dermatitis Group patch testing allergen series. Approximately 50 patches are applied to normal skin on the back in small metal chambers that are occluded with hypoallergenic tape. The patches are removed at 48 hours, marked to identify the spot and read initially with irritant contact pseudopositive tests, usually resolving by the delayed reading at 96 hours. Although the average nondermatology wound healer may not have access to patch tests, you can still perform your own detective investigation!
If you suspect an allergic contact reaction, choose a site of normal skin on the inner aspect of the forearm just below the elbow. Use a skin marking pen to create a circle the size of a silver dollar. Perform the Repeat Open Application Test by applying a cream or ointment twice a day for 3 to 5 days. If the patient is sensitive to that substance, a bright red well-demarcated patch or plaque will develop. You may not be certain what allergen(s) in the product the patient is sensitive to, but you can identify common allergens from the product ingredient list that are the most likely inciting agent(s).
Patients with venous disease also are prone to venous stasis dermatitis, an irritant contact dermatitis associated with lower leg edema and the leakage of red blood cells leaving residual-associated pigmentation around the malleoli of the ankles. These patients are very susceptible to developing severe localized allergic contact dermatitis. When this happens and the Langerhans cell in the skin processes the antigen, these cells migrate to the regional lymph nodes. Further recruitment of lymphocytes leads to migration to other skin body sites. Without touching the skin with the allergen, a generalized dermatitis can appear over the entire body, requiring systemic steroids for treatment. Patients with severe contact dermatitis have memory cells that will make any further exposures to be even more severe!
Every wound healer requires a basic knowledge of dermatitis and the common wound care complications that occur in atopic individuals with impaired skin barrier function along with the high incidence of irritant and allergic contact dermatitis complications for many chronic wound patients. We hope that this article and the others in this issue help our readers contextualize the “hole” in the whole patient.
R. Gary Sibbald, MD, DSc (Hons), MEd, BSc, FRCPC (Med Derm), FAAD, MAPWCA, JM
Elizabeth A. Ayello, PhD, MS, BSN, RN, CWON, ETN, MAPWCA, FAAN