Red, Scaly Rashes: Clinical Pearls

Matthew Zirwas, MD

What should we do with patients who present with red, scaly rashes? Dr Zirwas provides some of his clinical pearls from Maui Derm NP+PA Summer 2015…

  • Look behind the earlobes, under the jaw, and at the upper eyelids to distinguish between airborne contact dermatitis and photodermatitis;
  • Look for islands of sparing and ask if it started on the scalp when you’re considering pityriasis rubra pilaris;
  • With a widespread facial dermatitis, look for sharply demarcated red, scaly patches to diagnose seborrheic dermatitis, even if it isn’t in the normal distribution of seborrhea;
  • In cases of rosacea that don’t respond to treatment the way you expect, look for tiny, pinpoint pustules as a clue that demodex is the driving factor;
  • Dermatitis under a ring is essentially always irritant dermatitis from irritants trapped in the band. Fill in concavities on the inside of the band and only wear one ring per finger;
  • When the fingertips are the main place that is affected with a hand eczema, suspect friction with paper and keyboards as the most likely cause;
  • A rash under a bra-strap is most likely caused by symptomatic dermographism. Push-up bras with thin straps are most likely to cause problems.

10 Pearls About Pigmented Lesions

Whitney A. High, MD, JD, MEng

Dr Whitney High provides us with ten clinical pearls about pigmented lesions from the dermatopathologist’s point of view…

  • There are distinct histologic differences between wholly bland nevi, and what has come to be known as an “atypical nevus,” a “dysplastic nevus,” or a“Clark’s nevus.”
  • There is no single criterion (not even mitoses or pagetoid spread) that is diagnostic of only melanoma. There is not a “melanoma stain” that wholly discriminates between atypical nevi and melanoma. “Borderline” lesions represent subjective assessments that are impacted by the viewpoint and skill of the examiner.
  • Biopsy use is increasing. In nine geographic areas of the USA, over 1986-2001, the biopsy rate among those persons >65 years of age rose 5-fold, while the melanoma rate rose 2.4-fold.
  • In many areas of the country, atypical nevi are graded “mild,” “moderate,” or “severe,” but this is not universally employed. Some dermatopathologists “lump” mild and moderate together, and have just two categories. In other areas of the county nevi are not formally graded, or are graded in a less straight-forward way (i.e. “nevus,” “Clark’s nevus,” and “Clark’s nevus, re-excise”).
  • The dermatopathologist is examining only a small portion of your biopsy, and this must be considered with regard to the “representative” nature of the results. A 2010 study showed the odds of misdiagnosis for pigmented lesions were considerably higher when a punch biopsy technique was employed in comparison to an excisional biopsy (see: Ng et al. 2010).
  • There are special situations where the diagnosis of melanoma is challenging, such as:Screen Shot 2015-07-21 at 8.34.38 AM
  • There are some immunostains that can “assist” in the assessment of melanoma, or “bolster” the one’s confidence in a diagnosis, and these include: Mart1/Ki67 (a combination stain), P16, and HMB45, but again, there is, however, no singular “melanoma” stain.
  • Spitz nevi, in particular, may be confused with melanoma, and vice versa. Generally, if the patient is older than 20 years of age, it is wise to ensure that the dermatopathologist examining a case of a Spitz nevus or spitzoid melanoma has experience with difficult pigmented lesions.
  • Desmplastic nevi may be difficult to distinguish from other malignant processes (such as an atypical fibroxanthoma or spindle cell squamous cell carcinoma), and desmoplastic melanoma may also be confused with simple scarring, particularly in a shallow specimen. Stains and careful examination may often be employed in such a case.
  • Synoptic reporting (a “grid-like” summary) of characteristics that allow for the pathologic staging of melanoma is an emerging standard in dermatopathology, and probably more rapidly and more accurately transmits key therapeutic and prognostic information to the clinician.

Skin of Color: Clinical Pearls

Seemal Desai, MD

Here are some important takeaway messages from Dr Desai’s presentation on skin of color at Maui Derm Summer NP+PA:

  1. Erythema can be difficult to distinguish in patients with skin of color. Don’t be fooled by areas of violaceous hue, brownish discoloration, and bluish brown discoloration that can actually represent erythema and thus active inflammation. For example, in patients with psoriasis
  2. Progressive Macular Hypomelanosis is a condition commonly on the trunk, and can be seen in the distribution of tinea versicolor
  3. Treat acne vulgaris in patients with skin of color aggressively. These patients are more prone to post-inflammatory hyperpigmentation, which can be difficult to treat
  4. Inflammatory disorders such as sarcoidosis, cutaneous lupus, and infectious pathologies can mimic psoriasis in skin of color and vice-versa. Biopsy when in doubt
  5. First line therapy in the treatment of melasma consists of triple combination topical therapy, but second line therapy, including chemical peels should be considered for recalcitrant cases

Clinical Pearls: Nevus

Ashfaq Marghoob, MD

Here are some important takeaway points from Dr Marghoob’s presentation during the Pigmented Lesion session at Maui Derm NP+PA Summer 2015…

  • Globular nevi, reticular nevi, starburst nevi, homogeneous blue nevi are all biologically distinct subsets of nevi
  • Peripheral globular and starburst pattern correlate with the radial growth phase of dysplastic nevi and Spitz/Reeds nevi respectively
  • DN and Spitz nevi are markers for increased risk for developing melanoma
  • DN are markers for increased risk for melanoma and potential precursors to melanoma
  • Congenital nevi have a 1-5% risk for developing an associated melanoma
  • Screening for melanoma requires looking for lesions that are different, uneven in distribution of texture/color (ABCD), and/or changing
  • Dermoscopy improves the clinical sensitivity and specificity for cutaneous malignancy

Infectious Diseases: Clinical Pearls

Sheila Fallon-Friedlander, MD

What do we need to know about infectious diseases in our pediatric patients?

  • Remember that not all “infections” in atopic dermatitis are bacterial. HSV can infect AD lesions and the hint is “monomorphous, punched-out”
  • Rashes in neonates instill fear in family & staff alike – always first determine if the child appears ill, then set your “DefCon level”   Concern for molluscum is Defcon 5,   HSV is Defcon 1
  • Diaper dermatitis is a frustrating disease that can be infectious. Remember these possibilities:
    • Candida
    • Staph
    • Strep
    • Molluscum
  • Diaper dermatitis is frequently NOT infectious
    • MCI (baby wipes) irritant derm
    • Dyes from “colorful” diapers
    • Zinc /metabolic deficiencies
    • LCH
  • Measles is still an infectious disease concern world-wide. The risks of the vaccine are far outweighed by risk from the disease
  • Recent studies have shown that the measles vaccine can actually stimulate immune responsiveness