Pediatric psoriasis, eczema: Triggers and therapies

In part two of our discussion, Kelly Cordoro, M.D., associate professor of dermatology and pediatrics at the University of California in San Francisco, discusses environmental and microbial triggers and when to choose systemic therapies with Dermatology Times editorial advisor, Elaine Siegfried, M.D.

Check part one of this three part series: Clinical pearls in pediatric dermatology

Environmental and food triggers

Dr. Siegfried: On to the next controversy: Many parents are convinced that their child has an environmental or food trigger that can be easily identified and eliminated. How do you address this?

Dr. Cordoro: We call these families the search-and-destroy families. I will explain to them that I understand they are on a search-and-destroy mission, and then I tell them why it won’t work. We talk about the concept of food allergy and how it correlates with the skin condition. I think there’s a lot of misunderstanding as well as a general lack of education.

In the majority of patients, if not all, food allergy does not cause eczema, but it can contribute. I explain when we will test. I believe in what we wrote in the guidelines and what the data supports, which is why I will evaluate for food allergy if two conditions are met: The skin hasn’t responded to a good, comprehensive, skin-directed regimen; and the parents notice a relevant reaction to a specific food. If these two things happen, they get specific testing.

READ: Pediatric psoriasis

The most profound observation I have made in the clinic - and I am sure you have as well - is when a parent brings a child who is head-to-toe atopic dermatitis: scratching, digging, lichenified, oozing, weeping in some areas, bleeding in others, miserable, not sleeping, and that’s the same child who is on an elimination diet. It’s really hard to get the parents to make that mental link between having eliminated almost everything that they could be allergic to and yet the child is still in this state.

Two things that I spend the most amount of time counseling about are the idea that food can play a role, but it’s not the only thing that contributes to eczema; and steroid phobia.

Dr. Siegfried: Mark Boguniewicz, M.D., at Denver National Jewish Medical and Research Center, has a program in which patients with suspected food allergy travel great distances for food allergy evaluation.  Many of these patients also have severe eczema. The patients stay at a hotel across the street and receive intensive daily outpatient skin care. Once their skin is sufficiently cleared, they participate in double-blind, placebo-controlled food challenges.

 A 2010 retrospective analysis reviewed the outcomes of over 100 of these patients. Food challenges were negative to ~90% of the foods tested, especially in children on restricted diets for atopic dermatitis. Although these families have strictly avoided multiple foods for years, Dr. Boguniewicz was as amazed as you by their inability to recognize the limited impact that dietary restriction had on their child’s severe eczema. He is equally surprised by their hesitation to liberalize their child’s diet.  One of his biggest jobs is to help them overcome their fear of foods.

Dr. Cordoro: I’m glad to hear about that. I have not read that study. Dr. Boguniewicz has done some fabulous work on chronic urticaria as well. He is such a practical clinician researcher. I think that’s the type of information that parents need to hear and understand. I have also found that the quality in the information that the patients will receive from allergists is very disparate. Sometimes allergists understand this concept and sometimes they don’t. They may themselves be on an elimination mission.

NEXT: Microbial triggers

Microbial triggers

Dr. Siegfried: I’m a fan of looking for microbial triggers. Have you suspected herpes or group A Strep as a cause of eczema flares?

Dr. Cordoro: I swab the pharynx and the anus of all of my new psoriasis patients to look for subclinical strep infections. In the younger kids we have data and we know it’s a driver. When a child continues to flare despite a good regimen, I will check an antistreptolysin O titer, because data have shown that even if you can’t find a culture-proven infection in the tonsils or in the anus, there can be strep in other places driving the psoriasis.

In atopic dermatitis patients, I am very careful and selective about whom I swab. We know that if we swab an atopic dermatitis patient, 90% or more will be colonized,  but it doesn’t necessarily mean that in the absence of clinical infection it is driving their disease. I’ll typically only swab kids if they are actively clinically infected, and that is really to drive my choice of systemic antimicrobial if I go in that direction.

Often I’ll try to do skin-directed therapy like bleach baths, and I try to stay away from oral antibiotics if I can, unless they have strep, pustules, or [they’re] systemically ill.

READ: Probiotics for healthy skin

I look for herpes simplex virus (HSV) if there are typical punched-out lesions or a pattern that looks like HSV or eczema herpeticum with a culture or a direct fluorescent antibody study. So yes, I am very often looking for bugs.

Another pearl on psoriasis patients is that we can often overlook or forget in the clinic that there is some data that pityrosporum can drive scalp psoriasis. I will often prescribe an antifungal shampoo for my psoriasis patients who have scalp involvement, which I think can help in that regimen as well.

Some of the allergists would use itraconazole or related anti-fungals for atopic dermatitis. I am not sure that the potential benefit would outweigh the potential risk.

Check part one of this three part series: Clinical pearls in pediatric dermatology

Dr. Siegfried: I have not used itraconazole or fluconazole (Diflucan, Pfizer). The only time I use oral anti-yeast agents is in kids with recurrent diaper dermatitis, who often have a predilection for psoriasis and then sometimes secondary yeast. I find that if I culture yeast, it’s more useful to use a systemic antifungal than an oral one, because the reservoir for the yeast is their stool, and also because all of the topical anti-yeast agents, with the exception of nystatin ointment, are primary irritants.

Dr. Cordoro: I think topical Nystatin is the best for the reason you mentioned as well. A lot of these “oldie but goodie” time-proven medications are cycling back around as we’re forced to look for alternatives to the newest agents that are too expensive and no insurance plans will cover them.

NEXT: Assessing systemic treatments

Assessing systemic treatments

Dr. Siegfried: I have a very high index of suspicion for herpes, and have been frequently surprised by positive PCR or viral cultures from scrapings of clinically eczematous skin. I now look much closer for herpes, and have diagnosed several kids with what I call “herpes incognito,” because it doesn’t present with the classic punched-out lesions.  I think I had been under-recognizing it, and in some kids with severe eczema, I think herpes is a trigger in the same way that colonization with Staph aureus or pityrosporum can trigger eczema.  I first became aware of herpes incognito because the viral skin infection became more obvious in kids treated with systemic immunosuppressants.  Then I started looking for it before considering a systemic drug. So, that brings me to my next question, how do you know when a kid needs systemic treatment?

Dr. Cordoro: I don’t have formal criteria upon which I base the decision on whether to opt for systemic therapy for atopic dermatitis or psoriasis. I approach every patient individually.

Some patients I consider candidates for systemic therapy at their very first appointment. That can be based on disease severity or presence of comorbidities, such as arthritis. Equally importantly is the impact on the quality of life. If the psoriasis patient or the atopic dermatitis patient is miserable, failing to thrive, missing work or school days, they absolutely may get a systemic therapy on day one, appointment one.

READ: Childhood skin disease has unique challenges

Most of the time, I try to treat with combination topical regimens for both atopic dermatitis and psoriasis before deciding on the next steps. I think this is important because during this treatment time, you begin to understand the family dynamic, develop rapport, and establish a relationship with the family before you put them on a medication that requires a lot of monitoring, bloodwork and trust.

NEXT: 3 things to consider before using systemic therapy

3 things to consider before using systemic therapy

I have three unwavering principles that I consider when I am thinking about systemic therapy for atopic dermatitis or psoriasis, and these are in no particular order:

First, part of the rationale for systemic therapy is to diminish disabling symptoms such as pruritus, pain, arthralgia resulting in missed school days, lack of mobility, etc. One or more should be present and uncontrolled in candidates for systemic therapy.

Second, and equally important, is improving the patient’s quality of life. Especially with psoriasis patients, I want to prevent that potential for social stigma, bullying, social isolation and withdrawal. These patients are at higher risk of depression and other mood disorders. When present, in my opinion, that’s a rationale for systemic therapy in an effort to rapidly bring the disease under control. 

Check part one of this three part series: Clinical pearls in pediatric dermatology

The third thing, which is obvious to all of us, is preventing the complications and morbidity of the disease. For example, a patient who has generalized pustular psoriasis of Von Zumbusch is not going to get topical therapies. They can have serious consequences such as sepsis and even death. So those patients will get treated with a systemic therapy. Psoriatic arthropathy can lead to mutilating arthritis, so most of those patients will get a systemic.

I’ve been thinking a lot recently about this concept of the psoriatic march. We are all aware of the atopic march and how one aspect of the atopic triad may lead to the next. Is this true for psoriasis?  Will untreated inflammation of psoriasis lead to metabolic syndrome, insulin resistance and cardiovascular disease, which may put our pediatric patients at higher risk for myocardial infarction and stroke as young adults?

We need longitudinal data. I certainly don’t use the concept of the psoriatic march to provide a definitive rationale to put a pediatric psoriatic patient on long-term systemic therapy, but I certainly consider it and talk to the patients’ families about it.

There are data on risk of lymphoma in uncontrolled rheumatoid arthritis, patients, for example. We know that patients with psoriasis, particularly more severe disease and younger onset, have a risk for early heart attacks. This is really compelling information for us to wrestle with as pediatric dermatologists, and we should take this into account when managing our patients.

NEXT: Choosing systemic treatments

Choosing systemic treatments

Dr. Siegfried: How do you decide whether a patient needs systemic treatment and then how do you choose which one?

Dr. Cordoro: First of all, there are different drugs that we know historically, mechanistically, work better for different types of psoriasis. In those situations, it’s a given. For example, we know that thin guttate psoriasis will respond very well to oral retinoids, phototherapy, or both, while thick diffuse plaques are not going to respond as well to oral retinoids. 

Also there’s the risk-benefit analysis. In the discussion I have with parents, I talk about these specifically for the different treatments. At the end of the day, there is not an enormous difference in efficacy for atopic dermatitis between the various systemic agents. For psoriasis, I believe there is a difference in efficacy depending on the presenting morphology of the disease. So those are important clinical considerations.

Morphology often trumps everything else in terms of what you are going to use for psoriasis.  For example, if a patient has pustular psoriasis, they are probably going to need an oral retinoid or cyclosporine if it’s more rapidly moving. If the patient’s disease is really severe and the patient is hospitalized, he or she will likely need a TNF (tumor necrosis factor) inhibitor.

Check part one of this three part series: Clinical pearls in pediatric dermatology

There are few patterns I think we have established, and speed of progression is important. So if you need something that acts really quickly, you are going to reach for cyclosporine, because methotrexate does not work quickly for AD or psoriasis. The patient’s age and gender are considerations. None of us will use a retinoid in a girl of child-bearing potential, but retinoids are a fine consideration in boys of all ages, for example low dose acitretin for psoriasis. Level of disability should be considered, and the risks and benefits of individual drugs in individual patients. So for example, I might avoid methotrexate in a very obese child who may have fatty liver.

Then I think feasibility: How often is lab testing required, what’s the dosing schedule, does the patient have to visit an infusion center if you are choosing to use a biologic agent, etc. Finally, cost. Sadly, going back to where we started, I think cost oftentimes trumps a lot of these other considerations, particularly by way of biologics.

I don’t really have a gold nugget for systemic therapies for atopic dermatitis, other than what we just mentioned. In addition to patient and disease-related factors, choice of therapy often is based on your experience with the drugs, your comfort level, where you trained. We all have our favorites. I will say that I think azathioprine is the most potent agent for atopic dermatitis, but it’s probably also the one with the most risk.

NEXT: What's next

Next month, Dr. Cordoro will continue the discussion, focusing on screening labs, avoiding complacency, and the ABCDEs of melanoma.

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