Master the board step 3

Master the Boards: USMLE Step 3
Scaling Disorders (Eczema)/Papulosquamous
Dermatitis
Psoriasis
Silvery scales develop on the extensor surfaces. Psoriasis can be local or
enormously extensive. Nail pitting is a common accompaniment. A Koebner
phenomenon is the development of lesions to the site of an epidermal injury.
Treatment
All patients should use emollients, such as Eucerin, Lubriderm, Aquaphor, and
Vaseline or mineral oil. Salicylic acid is used to remove heaped up collections
of scaly material so the other therapies can make contact.
··
If the disease is relatively localized, topical steroids are used.
··
Severe disease also needs coal tar or anthralin derivatives.
··
To avoid the long-term use of steroids, which can cause skin atrophy, and to
avoid coal tars, which are messy, one can substitute topical vitamin D and
vitamin A derivatives. The vitamin D derivative most frequently used is
calcipotriene. Tazarotene is a topical vitamin A.
When > 30 percent of the body surface area is involved, it is difficult to use
topical therapy routinely to control disease. Such patients can be treated with
ultraviolet light. This is the most rapid way to control extensive disease.
The most severe, widespread, and progressive forms of the disease can be controlled
with methotrexate. However, this therapy has the highest toxicity and
may cause liver fibrosis.
The newest therapies are immunomodulatory biological agents, such as alefacept,
efalizumab, etanercept, and infliximab.
Xerosis/Asteatotic Dermatitis
Xerosis and dry skin are managed with humidifiers and emollients, such as
Lubriderm, Eucerin, Vaseline, Dermasil, mineral oil, or Lac-Hydrin. In those
whose skin is especially inflamed, topical steroids can be used briefly.
Atopic Dermatitis
This extraordinarily pruritic disorder presents with the following:
··
High IgE levels
··
Red, itchy plaques of the flexor surfaces
306