Contact Dermatitis and the Allergen of the Year, 2017

Contact dermatitis—recognizable for its localized rash or skin irritation—follows either exposure to allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis). Patients may have had brief, heavy exposures or prolonged, low exposures. Usually, patients present with superficial inflammation; it affects just the outermost epidermis and the underlying dermis. These rash-like areas can be quite small, perhaps involving just the area under an earring or a ring that is aggravated by an irritant, or very large, such as when patients have contact with airborne irritants.

Contact dermatitis’s burning, itchy manifestations can take several days to weeks to resolve. Sometimes, the symptoms also include blisters and scaling. And, contact dermatitis only fades if the patient avoids the allergen or irritant arduously.

Patients can develop contact dermatitis anywhere on their bodies. The irritant version—which accounts for about 80% of all contact dermatitis—often affects the hands, and careful questioning will reveal that the patient has washed with the offending agent, or been exposed in water. Often, irritant contact dermatitis is an occupational condition; patients are exposed to chemicals or substances in the course of the workday.

Allergen of the Year

The American Contact Dermatitis Society (ACDS) heightens awareness of specific allergens with an award that is akin to a Rotten Tomatoes award for a film. Called the “Allergen of the Year Award,” this dubious honor identifies common allergens that clinicians often fail to recognize. The “honored” substance, however, causes a significant amount of allergic contact dermatitis.

This year, ACDS brings attention to the alkyl glucosides. Usually used in cosmetics, alkyl glucosides are surfactants synthesized when industrial processes condense long-chain fatty alcohols and glucose from renewable plant sources (eg, palm or coconut oils). Alkyl glucosides are completely biodegradable. With greater attention to eco-friendly and natural components, cosmetic manufacturers have increased their use of and reliance on alkyl glucosides recently.

Since the early 2000s, dermatologists have identified significantly more cases of alkyl glucoside-induced allergic contact dermatitis than ever before.

Alkyl glucosides are found most often in leave-on and rinse-off cosmetics, skin care products, hair dyes, styling mousse, cleansing soaps, fragrances, and tanning formulations.

It’s unclear how many patients experience glucoside-induced allergic contact dermatitis, but ACDS indicates that underestimation is probable. Most cosmetics contain multiple glucosides, and current patch tests look only for decyl glucoside. Positive reactions to decyl glucoside have increased steadily.

What might a retail health clinician see if patients develop alkyl glucoside-induced allergic contact dermatitis? TheTablematches a few products to most likely symptoms.

TABLE:IRRITANT AGENTS AND THEIR SYMPTOMS

Irritant Agent

Symptoms and Notes

Sunscreens

• Eczema, largely distributed on the face
• Some eczema on the neck, arms, and upper chest

Shampoos

• Dermatitis primarily on the scalp
• Most obvious rash along the frontal hairline, back of the head, and nape of the neck
• Less likely (but possible) to see dermatitis on the face and trunk

Occupational exposures

• Eczematous plaques affect mainly the hands
• High-risk groups are hairdressers (from shampoos or hair care products) and health care personnel (from antiseptic agents or creams)

Treating Contact Dermatitis

The first advice for patients is to avoid the offending irritant; the second is to stop scratching. This may require a period of eliminating possible causes one by one until the offending agent is identified.

Patients can treat blisters and angry skin by applying cold damp compresses for 30 minutes, 3 times a day. Calamine lotion sometimes helps.

If itching is troublesome, patients can consider diphenhydramine at OTC doses or hydrocortisone cream as needed.

If patients anticipate exposure to the offending agent again, recommend wearing gloves or using a barrier cream that contains zinc oxide.

Rashes that fail to improve after 2 to 3 days or that create severe itching or pain may require prescription-strength corticosteroids. When the rash is widespread, systemic corticosteroids may be warranted.

Sources

Alfalah M, Loranger C, Sasseville D. Alkyl Glucosides.Dermatitis.2017;28(1):3-4. doi: 10.1097/DER.0000000000000234.

Canadian Centre of Occupational Health and Safety. Dermatitis, irritant contact. ccohs.ca/oshanswers/diseases/dermatitis.html. Accessed February 3, 2017.

Hogan DJ, James WD. Irritant contact dermatitis. emedicine.medscape.com/article/1049353-overview#a4. Updated September 26, 2016. Accessed February 3, 2017.

Loranger C, Alfalah M, Ferrier Le Bouedec MC, Sasseville D. Alkyl glucosides in contact dermatitis.Dermatitis.2017;28(1):5-13. doi: 10.1097/DER.0000000000000240