Gary W. Cole, MD, FAAD
Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Rash facts
- What are the causes, symptoms, and signs of common noninfectious rashes?
- How are common skin rashes diagnosed?
- Scaly patches of skin produced by fungal or bacterial infection
- What is the treatment for a rash?
- Pictures of Adult Skin Problems - Slideshow
- Pictures of Child Skin Problems - Slideshow
- Gallery of Skin Problems Pictures and Images Collection
- Skin FAQs
- Find a local Dermatologist in your town
How are common skin rashes diagnosed?
The term rash has no precise meaning but often is used to refer to a wide variety of red skin eruptions. A rash is any inflammatory condition of the skin. Dermatologists have developed various terms to describe skin rashes. The first requirement is to identify a primary, most frequent feature. The configuration of the rash is then described using adjectives such as "circular," "ring-shaped," "linear," and "snake-like." Other characteristics of the rash that are noted include density, color, size, consistency, tenderness, shape, and even temperature. Finally, the distribution of the rash on the body can be very useful in diagnosis since many skin diseases have a predilection to appear in certain body areas. Although certain findings may be a very dramatic component of the skin disorder, they may be of limited value in producing an accurate diagnosis. These include findings such as ulcers, scaling, and scabbing. Using this framework, it is often possible to develop a small listing of the possible diseases to be considered. Below is a short discussion of some common categories of skin rashes:
- Rashes produced by fungal or bacterial infection
- Noninfectious, common rashes
Self-diagnosis of a rash is not usually a good idea. Rashes that quickly resolve are generally not dangerous. Proper evaluation of a skin rash requires a visit to a doctor or other health-care professional.
Scaly patches of skin produced by fungal or bacterial infection
When infections appear as rashes, the most common culprits are fungal or bacterial infections.
Symptoms, signs, and treatment of fungal infections
Fungal infections are fairly common but don't appear nearly as often as rashes in the eczema category. Perhaps the most common diagnostic mistake made by both patients and physicians is to almost automatically call scaly rashes "a fungus." For instance, someone with several scaly spots on the arms, legs, or torso is much more likely to have a form of eczema or dermatitis than actual ringworm (the layman's term for fungus). Likewise, yeasts are botanically related to fungi and can cause skin rashes. These tend to affect folds of skin (like the skin under the breasts or the groin). They look fiery red and have pustules around the edges. As is the case with ringworm, many rashes that are no more than eczema or irritation get mislabeled "yeast infections."
Fungus and yeast infections have little to do with hygiene -- clean people get them as well. Despite their reputation, fungal rashes are not commonly acquired from dogs or other animals. They seem to be most easily acquired in gyms, showers, pools, or locker rooms or from other family members. Treatment is usually straightforward. Many effective antifungal creams can be bought at the drugstore without a prescription, including 1% clotrimazole (Lotrimin, Mycelex) and 1% terbinafine (Lamisil). In extensive cases, or when toenails are involved, a prescription drug like oral terbinafine may be useful.
If a fungus has been repeatedly treated without success, it is worthwhile considering the possibility that it was never really a fungus to begin with but rather a form of eczema. Eczema is treated entirely differently. A fungal infection can be independently confirmed by performing a variety of simple tests.
Symptoms, signs, and treatment of bacterial infections
The most common bacterial infections of the skin are folliculitis and impetigo. Both may caused by staph or strep germs and are much more common in children than adults. Eruptions caused by bacteria are often pustular (the bumps are topped by pus) or may be plaque-like and quite painful (such as with cellulitis). Again, poor hygiene plays little or no role. Nonprescription antibacterial creams like bacitracin (Neosporin) are not very effective. Oral antibiotics or prescription-strength creams like mupirocin (Bactroban) are usually needed.
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