An early presentation of scabies may also present similar to an eczema rash. Treatment with topical corticosteroids can delay diagnosis of scabies as they may decrease the presentation of excoriated papules and burrows. Scabietic nodules are a late presentation and are often found in the web spaces of the hands and feet. A scabies mite, ova, or stool detected on an oil prep slide is an obvious a positive indication of a scabies infestation, however, mites are not commonly identified on an oil prep slide.
There are multiple reasons a slide might be negative — either the skin scraping is too superficial, or the mite may have moved on. Positive or negative slide aside, the decision for treatment is often determined based on clinical suspicion.
The most common treatment is permethrin 5% cream applied from neck to feet for 8 to 14 hours to be repeated in a week. Ivermectin dosed at 0.2mg/kg as a single dose is another popular therapy because of the convenience of single dose. An important aspect of scabies treatment is patient education about personal and home hygiene. If the home is not cleaned, a recurrence of the infestation is likely.
Ms. SA may have originally presented with scabies that was missed, but in the treatment failures, there was also success in correctly diagnosing and treating two other rashes.
The dermatitis patient can be extremely complex in their presentation, as well as have multiple dermatoses complicating the diagnosis. It is important to remember to take a good history before you start your physical exam. Histories help in the accurate diagnosis of dermatoses. Consider a wide range of differentials and narrow your therapies as you narrow your differential range.
B. Jang Mi Johnson, PA-C, is the senior physician assistant at Illinois Dermatology Institute, specializing in surgical and general dermatology.
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All electronic resources were accessed on March 18, 2015.