Perioral dermatitis: Differential diagnosis tricky

National report - Scaly, erythematous papular and papulopustular rashes on the face are a common sight for dermatologists, and a number of possible diagnoses come to mind.

When these eruptions are concentrated mostly perinasally and around the mouth, experienced dermatologists diagnose perioral dermatitis (POD). Yet novice dermatologists must be wary not to use perioral dermatitis as a waste paper basket diagnosis. This eruption can mimic several other dermatoses, each having a different etiology.

Nikki A. Levin, M.D., Ph.D., associate professor of medicine in the division of dermatology at University of Massachusetts Medical School, Worcester, Mass., offered her experience and insight on recognizing perioral dermatitis and how best to treat this chameleon-like dermatosis.

Dr. Levin says, "There are many different factors that can exacerbate this common dermatosis, with corticosteroids being by far the most commonly cited precipitant, constituting 85 percent to 90 percent of presenting cases. Patients with an atopic diathesis and altered skin barrier are also at high risk for POD. Atopy may predispose patients to POD per se or it may predispose them to having potent topical corticosteroids in their possession that, in turn, may lead to POD. Patients who use foundations, moisturizers and make-up have a 13-fold increased risk to develop POD over those who use none of these. Although hormonal factors have been suggested as a cause of POD due to the female predominance, there is no correlation with the use of oral contraceptives or with the phase of the menstrual cycle."

Dr. Levin cites studies in which toothpaste ingredients, such as fluoride and anti-tartar agents, are implicated. In a case series of 65 patients with POD, all had used fluoride toothpastes. Half of the patients cleared when they made the switch to a non-fluoride toothpaste and the rest cleared upon switching to baking soda.

In another case series of 20 patients with POD, all had used tartar control toothpaste. All of these patients cleared with avoidance of this toothpaste. Interestingly, when 11 of these patients were rechallenged with tartar control toothpaste three times a day, a recurrence was noticed in all of the patients.

Typical areas of involvement

The typical areas of involvement of POD are around the mouth with a narrow zone of sparing around the vermillion border of the lips, as well as the chin, upper lip and perinasal skin.

Less common areas include the periocular skin, eyelids, glabella and the forehead. Here, it is important to note that the periocular skin may be involved with the absence of any perioral involvement.

Be wary, clinicians

Rosacea and seborrheic dermatitis belong on the long list of differential diagnoses, but can be ruled out because of the characteristic telangiectasia, erythema and facial flushing seen in rosacea (and not in POD), and seborrheic dermatitis is usually more scaly than papular and also tends to involve the eyebrows, scalp and forehead.

Contrary to POD, lip licker's dermatitis presents as a confluent erythema, scale and crust in a contiguous distribution without papules or pustules, and acne vulgaris can present with comedones affecting the cheeks, forehead, back, shoulders and chest areas and not only the perioral skin as in POD.

Less experienced clinicians might confuse POD with a contact dermatitis. This rash is characterized by erythema, scale and crusts and may occur around the mouth due to allergy to lip cosmetics, gum, candy, food, dental appliances and musical instruments. The difference is that a contact dermatitis is typically pruritic and usually has sharply defined borders, whereas POD is papular and usually has non-distinct margins.

Dr. Levin says that other differential diagnoses that the clinician must always keep in mind include demodex infestation, papular sarcoidosis, lupus miliaris disseminatus faciei, familial juvenile systemic granulomatosis, eruptive syringomas or xanthomas, and acrodermatitis enteropathica, most of which are not confined to the centro-facial skin and/or present with more than just erythematous papules.

Essential to treatment

"The discontinuation of topical corticosteroids is essential to treat POD," Dr. Levin says. "The patient should be warned that this will most likely cause a temporary flare of the rash. Substituting less potent corticosteroids in a tapering fashion may prevent the flare and improve patient compliance. The patient should also stop using facial moisturizers and make-up."