Krafchik: From a clinical standpoint, perhaps the most important impact of disposable diapers has been the decrease in the number of cases of diaper dermatitis that we see. Much of this change is due to the superabsorbent material that's been added to the inner core of the diaper. This material absorbs urine to form a gel that will not release the moisture from the diaper back to the skin. The ability of the superabsorbent material to reduce skin wetness and therefore reduce the incidence and severity of diaper dermatitis has been documented in several clinical studies.
Spraker: I concur that we dermatologists don't see as much diaper dermatitis as we did a few years ago, perhaps because it's being treated more effectively with first-line therapy by pediatricians. Dr. Schuman, as a general pediatrician, what's your impression of diaper dermatitis incidence now?
Schuman: On behalf of my pediatrician colleagues, I appreciate the compliment that we're doing a better job than we used to do. But the reality is that I definitely am seeing much less irritant diaper dermatitis - and possibly less Candida - now than I did a few years ago, and I see 30 to 40 patients a day, many of them in diapers.
Krafchik: Dermatitis caused by detergents and soaps is also rare today, and we're not seeing Jacquet's erosive diaper dermatitis now as we used to in the 1970s and before.
Schuman: I agree that the change is related to the superabsorbent material added to the diaper core in the mid-1980s. It's important to remember that the ability of the superabsorbent material to absorb urine has been regularly improved since then. I see virtually no cloth diapers in my practice now, and it's normal to see only one case of diaper rash per week compared with many per day only 2 or 3 years ago.
Leyden: I would agree that diaper rashes of what I like to call the friction-induced or irritant variety are significantly reduced today in terms of both number and severity. But I'm not sure that the incidence or the prevalence of Candida albicans-induced diaper rash, particularly in children given amoxicillin for middle ear infections, has been influenced yet.
Spraker: Dr. Schuman, has there been any change in your practice with respect to antibiotic choice for middle ear infections?
Schuman: Yes. I'm quite sensitive to the claim that general practitioners and pediatricians have been overprescribing antibiotics for a long time, so I've been trying to prescribe them less. The thinking now is that in some situations you may not need to use antibiotics. There have been studies showing that middle ear infections can resolve by themselves. However, I'm not sure what role that plays in the reduced incidence of diaper rash.
Leyden: But if you see a child with a middle ear infection and you decide you're going to prescribe an antibiotic, which would you use?
Schuman: Usually my first-line choice is amoxicillin, but at a higher dose than what was recommended previously.
Leyden: That's my point. Ampicillin and amoxicillin - which is ampicillin with a side chain - are particularly adept at selecting out Candida and allowing it to overgrow in the gastrointestinal tract.
Spraker: Is that more true for ampicillin and amoxicillin than it is for the cephalosporins, which are more commonly used in treating middle ear infections than they were 10 years ago?
Leyden: Yes. And if there has been a general change in prescribing, that could have an effect on the incidence of Candida dermatitis.
Spraker: Dr. Leyden, do you know why ampicillin and its derivatives would be more likely to promote Candida selection?
Leyden: I don't know the reason, but I know that it happens. I was involved in studies in the late 1960s on the effect of antibiotics on the gastrointestinal flora. We were particularly interested in how fast the flora became resistant and what ecologic changes would occur as a result. It was quite clear at that time that ampicillin had the greatest effect, with tetracycline second. There was less resistance to erythromycin and the sulfonamides. We did a similar prospective study at Children's Hospital in Philadelphia. Most of those children were being given ampicillin, and it clearly changed the flora to allow overgrowth of Candida, if any was present initially.
Spraker: Why don't more babies get Candida diaper dermatitis? A large proportion of infants have gastrointestinal colonization of Candida.
Leyden: Actually, a large number of infants have low numbers of Candida in their stool. The use of selective media is required to demonstrate this colonization. However, if Candida is present, its growth increases dramatically when the baby is given ampicillin or amoxicillin. Many other investigators have concluded that Candida is a secondary rather than a primary factor. I disagree, as do others who have studied Candida. Part of the problem is that when you see a child with a severe rash and you suspect Candida, often it is difficult to demonstrate its presence on inflamed skin. If you inoculate C albicans onto your forearm and occlude it with a dressing, in 24 to 48 hours you'll have a papulopustular eruption that will become increasingly inflamed. But if you then remove the dressing for a brief period and look at that site the next day, you won't be able to find Candida even though the area will still be inflamed. We tested that. We took infants who had Candida in satellite pustules but not in the highly inflamed areas of a severe diaper rash. We asked the parents to keep these babies out of diapers for 2 days. When they came back 2 days later, the whole diaper area was fiery red, and we were unable to culture Candida anywhere unless we did a rectal swab. Yet 2 days earlier we had been able to grow the organism from skin samples. So the ability to grow Candida depends on when you come in on the sequence of events.
Schuman: Would you therefore advise treating an irritant dermatitis routinely with an antifungal?
Leyden: I don't see much irritant diaper rash, though general pediatricians do. The majority of cases I see as a specialist are of the more severe variety, and I suspect Candida in that setting. My approach for these severe cases is to give the infants an oral antifungal such as nystatin to eliminate the gastrointestinal reservoir and to treat the skin with a topical antifungal and topical low-strength corticosteroid. Not everyone agrees with me.
Krafchik: A group in Montreal studied this question and concluded that using an oral antifungal made no difference in the outcome. They concluded that after 2 to 3 weeks, infants treated orally with nystatin and topically with antifungal creams had the same result as those who received just topical treatment.
Leyden: If you look at the end of 3 weeks and the child's no longer on antibiotics and the gastrointestinal flora is adjusting, that's true. But if you look after just one week, there's a big difference.
Krafchik: You've written about adding hydrocortisone topically.
Leyden: Yes, to treat the inflammatory response.
Krafchik: Did you do a comparative study? Do you really feel that it makes a difference?
Leyden: Yes, absolutely. We set up an experimental system in which multiple sites were inoculated with the same number of yeasts and occluded in the same way. In these volunteers, who were inoculated with C albicans on several sites on each forearm, we were able to compare the effects of various treatments. The addition of a low-strength steroid significantly reduced the degree of inflammation compared with that of an antifungal agent used alone.
Krafchik: I think we can summarize by saying that several studies have documented an overall decrease in diaper dermatitis and that this has also been seen in clinical practice. As Dr. Schuman suggested, I think that decrease has to be related to the superabsorbent material.
Schuman: Yes, and I think we'll continue to see improvements. The amount of superabsorbent material in diapers has been increased and the amount of cellulose has decreased. That has improved the diaper's ability to draw moisture away from the skin. Other components have also been added to help keep skin dry - for example, acquisition layers that hold the urine and wick it through faster and more evenly to the superabsorbent material. They help prevent the "re-wet" phenomenon that used to occur when a child would sit on the diaper and push the moisture back through to the inner layer. We'll be talking more about this later. I've also noticed that there's less chafing because of improvements in the fasteners. That's significant, because if there's skin breakdown or irritation around the fasteners, often what follows is a full-blown rash. Disposable diapers have also had a positive impact with respect to transmission of infection. Studies have been done on the spread of fecal material from one child to another, to a day-care worker, and to inanimate surfaces. These studies show that there's much less transmission of potentially infectious agents when disposables are used. That's a very important contribution.