Share |

Rash, Rashes, and the Art of Skin Diagnosis | Part 1

Self-paced online dermatology course

The word “rash” or “skin rash” is used quite frequently to describe a variety of skin conditions. 

Rash is a generic term however and most people use the word rash to mean an eruption of skin lesions that covers areas of skin. In contrast, a single small lesion, like a pimple, mole, tumor, or growth, is not usually called a rash. 

Properly diagnosing and treating a skin condition requires a more detailed understanding of the true cause of the condition. 

In most situations simply using the term “skin rash” is not adequate.

Lowell Goldsmith

The art and science of figuring out the cause of a rash involve determining its time course and features and specifically describing the type, shape, arrangement, distribution, size, color, and other features of the skin lesions using standard medical vocabulary.

The field of dermatology has a well-established terminology for describing skin lesions. These descriptive terms facilitate the diagnostic process because many diseases have distinctive features that fall into recognizable categories.

This course is designed to:

  • Introduce students of all backgrounds to the key terms and clinical concepts of dermatology.
  • Provide an introduction to the top list of dermatology conditions with which all students and clinicians should be
    familiar.
  • Increase exposure to building a robust differential based on
    the specific findings of a patient.
The final sections of this course are design to work as a companion with VisualDx -- the leading dermatologic decision support system.  If you or your institution has access to VisualDx, simply log in to take advantage of this interactive content.  A free trial is also available for those who are new to the system.
 
Rash diagnosis in action: A patient has tiny fluid-filled blisters (vesicles). A list of diseases that can cause vesicles, such as cold sores caused by the herpes simplex virus, should come to mind. The addition of details such as the location, color, shape, and distribution – for example, “on the right mid-trunk, there are small, grouped vesicles in a band-like or dermatomal distribution” – would narrow the diagnostic possibilities and immediately suggest the diagnosis of shingles (herpes zoster).
 
Clinical images from VisualDx of skin rash location, distribution, and morphology.
 
Dermatomal vesicle
Vesicle
 Vesicle