Tinea corporis is a superficial dermatophyte infection characterized by either inflammatory or noninflammatory lesions on the glabrous skin (ie, skin regions other than the scalp, groin, palms, and soles).  Three anamorphic (asexual or imperfect) genera cause dermatophytoses: Trichophyton, Microsporum, and Epidermophyton. Dermatophytes may infect humans (anthropophilic) or nonhuman mammals (zoophilic), or they may reside primarily in the soil (geophilic).
Signs and symptoms
Tinea corporis can manifest as follows:
- Typically, the lesion begins as an erythematous, scaly plaque that may rapidly worsen (see the image below)
- Following central resolution, the lesion may become annular in shape (see the image below)
The inflammation can cause scale, crust, papules, vesicles, and even bullae to develop, especially in the advancing border
Rarely, tinea corporis can present as purpuric macules
Infections due to zoophilic or geophilic dermatophytes may produce a more intense inflammatory response than those caused by anthropophilic microbes.
Patients who are immunocompromised or infected with the human immunodeficiency virus (HIV) often have atypical presentations, including deep abscesses or a disseminated skin infection.
This variant of tinea corporis is a fungal infection of the hair, hair follicles, and, often, surrounding dermis. Typically caused by Trichophyton rubrum, it manifests as perifollicular, granulomatous nodules typically in a distinct location, which is the lower two thirds of the leg in females, with an associated granulomatous reaction. Majocchi granuloma often occurs in females who shave their legs.
Tinea corporis gladiatorum
This variant is a dermatophyte infection spread by skin-to-skin contact between wrestlers [2, 3] ; it often manifests on the head, neck, and arms, which is a distribution consistent with the areas of contact in wrestling.
Another variant of tinea corporis, this form is found mainly in Southeast Asia, the South Pacific, Central America, and South America. Tinea imbricata is caused by T concentricum  and is recognized clinically by its distinct, scaly plaques arranged in concentric rings.
This is tinea corporis with an altered, nonclassic presentation due to corticosteroid treatment. 
See Clinical Presentation for more detail.
A potassium hydroxide (KOH) examination of skin scrapings, used to visualize fungal elements removed from the skin's stratum corneum, may be diagnostic in tinea corporis.
A fungal culture, which is often used as an adjunct to KOH for diagnosis, is more specific than KOH for detecting a dermatophyte infection. Therefore, if the clinical suspicion is high yet the KOH result is negative, a fungal culture should be obtained.
If the above clinical evaluations are inconclusive, a polymerase chain reaction (PCR) assay for fungal deoxyribonucleic acid (DNA) identification can be used. 
For atypical presentations of tinea corporis, further evaluation for HIV infection and/or an immunocompromised state should be considered.
A skin biopsy specimen with hematoxylin and eosin staining of tinea corporis demonstrates spongiosis, parakeratosis, and a superficial inflammatory infiltrate. Neutrophils may be seen in the stratum corneum, which is a significant diagnostic clue. On occasion, septate branching hyphae are seen in the stratum corneum with hematoxylin and eosin stain, but special fungal stains (eg, periodic acid-Schiff, Gomori methenamine silver) may be required.
See Workup for more detail.
Topical therapy is recommended for a localized infection because dermatophytes rarely invade living tissues. Topical azoles and allylamines show high rates of clinical efficacy; these agents inhibit the synthesis of ergosterol, a major fungal cell ̶ membrane sterol.
The topical azoles inhibit the enzyme lanosterol 14-alpha-demethylase, a cytochrome P-450–dependent enzyme that converts lanosterol to ergosterol. Inhibition of this enzyme results in unstable fungal cell membranes and causes membrane leakage.
Allylamines (eg, naftifine, terbinafine) and the related benzylamine butenafine inhibit squalene epoxidase, which converts squalene to ergosterol. Inhibition of this enzyme causes squalene, a substance toxic to fungal cells, to accumulate intracellularly and leads to rapid cell death. Allylamines bind effectively to the stratum corneum because of their lipophilic nature. They also penetrate deeply into hair follicles. 
Systemic therapy may be indicated if tinea corporis includes extensive skin infection, immunosuppression, resistance to topical antifungal therapy, or the comorbid presence of tinea capitis or tinea unguium.
See Treatment and Medication for more detail.
The Modes of Discourse—Exposition, Description, Narration, Argumentation (EDNA)—are common paper assignments you may encounter in your writing classes. Although these genres have been criticized by some composition scholars, the Purdue OWL recognizes the wide spread use of these approaches and students’ need to understand and produce them.
Contributors: Jack Baker, Allen Brizee, Elizabeth Angeli
Last Edited: 2013-03-10 01:34:44
What is a descriptive essay?
The descriptive essay is a genre of essay that asks the student to describe something—object, person, place, experience, emotion, situation, etc. This genre encourages the student’s ability to create a written account of a particular experience. What is more, this genre allows for a great deal of artistic freedom (the goal of which is to paint an image that is vivid and moving in the mind of the reader).
One might benefit from keeping in mind this simple maxim: If the reader is unable to clearly form an impression of the thing that you are describing, try, try again!
Here are some guidelines for writing a descriptive essay.
If your instructor asks you to describe your favorite food, make sure that you jot down some ideas before you begin describing it. For instance, if you choose pizza, you might start by writing down a few words: sauce, cheese, crust, pepperoni, sausage, spices, hot, melted, etc. Once you have written down some words, you can begin by compiling descriptive lists for each one.
- Use clear and concise language.
This means that words are chosen carefully, particularly for their relevancy in relation to that which you are intending to describe.
Why use horse when you can choose stallion? Why not use tempestuous instead of violent? Or why not miserly in place of cheap? Such choices form a firmer image in the mind of the reader and often times offer nuanced meanings that serve better one’s purpose.
Remember, if you are describing something, you need to be appealing to the senses of the reader. Explain how the thing smelled, felt, sounded, tasted, or looked. Embellish the moment with senses.
If you can describe emotions or feelings related to your topic, you will connect with the reader on a deeper level. Many have felt crushing loss in their lives, or ecstatic joy, or mild complacency. Tap into this emotional reservoir in order to achieve your full descriptive potential.
- Leave the reader with a clear impression.
One of your goals is to evoke a strong sense of familiarity and appreciation in the reader. If your reader can walk away from the essay craving the very pizza you just described, you are on your way to writing effective descriptive essays.
It is easy to fall into an incoherent rambling of emotions and senses when writing a descriptive essay. However, you must strive to present an organized and logical description if the reader is to come away from the essay with a cogent sense of what it is you are attempting to describe.