For Professionals

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. 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. Part 2: Observing the Skin

Disciplined and thorough observation is key to describing the features of a rash accurately. Understanding and mastering each of the steps in the process is critical to making an accurate diagnosis. The Skin Exam Process Click each of the following steps for an interactive tutorial.Lesson 1. The first step is to learn how dermatologists perform a skin exam. Lesson 2. Describe what you see by using standard dermatologic terminology. Lesson 3. Describe the locations and distributions of the skin lesions. Lesson 4. Learn the terms for shapes and configurations. Experts put these features together as they examine the skin, hair, nails, and mucous membranes. Many common rash patterns are so characteristic that a diagnosis can be made with no history at all. In other cases, such as viral exanthems, the history of the eruption can clinch the diagnosis. Part 3: Skin Disease Variation

Some diagnoses can have multiple different features. Common diseases can be difficult for the novice diagnostician when they appear in an unusual location or have a different shape than what is typically found. Lesson 5. Learn the reasons for disease variation, and you will be a better diagnostician. There are many additional clues that can be leveraged to help your diagnostic process. The term rash, in itself, usually implies an abrupt onset, so it is rare for a patient with a slow-growing tumor or a seborrheic keratosis to call such lesions a rash. It might be called a bump or blemish or spot or growth or mole or lesion. (Patients will hardly ever use the word tumor.) In the case of acute rashes, the history is often critical. Did the patient start taking a new drug? Did the patient have a tick bite? Eat a lobster? Historical features of importance include the age of the patient, the speed or timing in which the rash occurred, the presence of symptoms such as itch (pruritus) or tenderness, as well as other symptoms such as muscle aches or joint pain. A rash with a fever can be a medical emergency, and patients with fever and a rash should be evaluated immediately. Part 4: Differential Diagnosis of an Unusual Rash

If you can accurately describe a rash and have taken a basic patient history, you are very close to a diagnosis. While the “common lists” can serve as a foundational dermatology curriculum for medical student education and help with common disease diagnosis, arriving at a diagnosis when a patient presents with an unusual rash and a complex medical history can be challenging. Case Study Consider a 28-year-old patient who has recently returned from work with the Peace Corps in Haiti and is presenting with widespread, blanching macules and a prominent fever.If you are medical student or resident at an institution with access to VisualDx, click here to log in or use a 15-day free trial to build your differential diagnosis within the Fever and Rash module, now that you are an expert in the language of dermatology. (See below for the findings entry search sequence for the example above.) Search I:  Differential diagnosis of blanching macules in a patient with fever (using VisualDx) Search 2: Differential diagnosis where a widespread distribution of macules is considered (using VisualDx)Search 3: Differential diagnosis of blanching macules, widespread distribution, and arthralgias (using VisualDx)Search 4: Differential diagnosis of blanching macules, widespread distribution, arthralgias, and travel to Haiti (using VisualDx) For Patients:To understand the differential diagnostic process by using an age and body location diagnostic approach, try the Rash Skin Condition Finder. Part 5: Common and Serious Dermatologic Conditions

Every health care professional should know the 50 essential diagnoses included within the “Top 10” lists below. Melanoma, psoriasis, warts, zoster (shingles), and more are included. Review diagnoses by clicking the links below: The Top 10 Itchiest Rashes The Most Common Causes of Rash Serious Rashes Every Student and Clinician Should Know The Top 10 Common Causes of Face Rash Common and Serious Solitary Skin Lesions