Tinea versicolor
Template:Short description Template:Distinguish Template:Infobox medical condition (new) Tinea versicolor (also pityriasis versicolor) is a condition characterized by a skin eruption on the trunk and proximal extremities.<ref name="Bolognia" /> The majority of tinea versicolor is caused by the fungus Malassezia globosa, although Malassezia furfur is responsible for a small number of cases.<ref name="ReferenceA">Template:Cite journal</ref><ref>Template:Cite journal</ref> These yeasts are normally found on the human skin and become troublesome only under certain conditions, such as a warm and humid environment, although the exact conditions that cause initiation of the disease process are poorly understood.<ref name="ReferenceA"/><ref name="Weedon, D 2002">Template:Cite book</ref>
The condition pityriasis versicolor was first identified in 1846.<ref name="pmid17642908">Template:Cite journal</ref> Versicolor comes from the Latin {{#invoke:Lang|lang}} 'to turn' + color.<ref>Template:Cite encyclopedia</ref>
It is commonly referred to as Peter Elam's disease in many parts of South Asia.<ref name="PMC4030364">Template:Cite journal</ref>
Signs and symptomsEdit
The signs of this condition include:
- Occasional fine scaling of the skin producing a very superficial ash-like scale
- Pale, dark tan, or pink in color, with a reddish undertone that can darken when the patient is overheated, such as in a hot shower or during/after exercise. Tanning typically makes the affected areas contrast more starkly with the surrounding skin.<ref>{{#invoke:citation/CS1|citation
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- Sharp border<ref name="dermnetnz.org">Pityriasis versicolor | DermNet New Zealand Template:Webarchive. Dermnetnz.org. Retrieved on 2016-10-14.</ref>
Pityriasis versicolor is more common in hot, humid climates or in those who sweat heavily, so it may recur each summer.<ref name="dermnetnz.org"/>
The yeasts can often be seen under the microscope within the lesions and typically have a so-called "spaghetti and meatball appearance"<ref name="urlAdolescent Health Curriculum - Medical Problems - Dermatology - Papulosquamous Lesions (B4)">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> as the round yeasts produce filaments.
In people with dark skin tones, pigmentary changes such as hypopigmentation (loss of color) are common, while in those with lighter skin color, hyperpigmentation (increase in skin color) is more common. Because infected skin tans less than uninfected skin, resulting in uneven tanning, the term "sun fungus" is sometimes used.<ref name="urlTioconazole (Topical Route) - MayoClinic.com">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
PathophysiologyEdit
In cases of tinea versicolor caused by the fungus Malassezia furfur, lightening of the skin occurs due to the fungus's production of azelaic acid, which has a slight bleaching effect.<ref name=Vary2015>Template:Cite journal</ref>
DiagnosisEdit
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Tinea versicolor may be diagnosed by a potassium hydroxide (KOH) preparation and lesions may fluoresce copper-orange when exposed to Wood's lamp (UV-A light).<ref name="Athlete">Template:Cite journal</ref> The differential diagnosis for tinea versicolor infection includes:Template:Citation needed
- Progressive macular hypomelanosis
- Pityriasis alba
- Pityriasis rosea
- Seborrheic dermatitis
- Erythrasma
- Vitiligo
- Leprosy
- Syphilis
- Post-inflammatory hypopigmentation
TreatmentEdit
Treatments for tinea versicolor include:
- Topical antifungal medications containing selenium sulfide are often recommended.<ref name="Athlete"/> Ketoconazole (Nizoral ointment and shampoo) is another treatment. It is normally applied to dry skin and washed off after 20 minutes, repeated daily for two weeks.Template:Citation needed Ciclopirox (ciclopirox olamine) is an alternative treatment to ketoconazole, as it suppresses growth of the yeast Malassezia furfur. Initial results show similar efficacy to ketoconazole with a relative increase in subjective symptom relief due to its inherent anti-inflammatory properties.<ref>Template:Cite journal</ref> Other topical antifungal agents such as clotrimazole, miconazole, terbinafine, or zinc pyrithione can lessen symptoms in some patients.<ref>Template:Cite journal</ref> Additionally, hydrogen peroxide has been known to lessen symptoms and, on certain occasions, remove the problem, although permanent scarring has occurred with this treatment in some people.Template:Citation needed Clotrimazole is also used combined with selenium sulfide.Template:Citation needed
- Oral medications are viewed as a second-line of treatment for pityriasis versicolor in the event of widespread, severe, recalcitrant or recurrent cases. Systemic therapies include itraconazole (200 mg daily for seven days) and fluconazole (150 to 300 mg weekly dose for 2 to 4 weeks) that are preferred to oral ketoconazole which is no longer approved due to its potential hepatotoxic side effects.<ref name="Karray McKinney 2021 p. ">Template:CitationFile:CC-BY icon.svg Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Template:Webarchive.</ref> The single-dose regimens and pulse therapy regimens can be made more effective by having the patient exercise 1–2 hours after the dose, to induce sweating. The sweat is allowed to evaporate, and showering is delayed for a day, leaving a film of the medication on the skin.<ref>Ketoconazole Template:Webarchive. Fpnotebook.com. Retrieved on 2016-10-14.</ref>
EpidemiologyEdit
This skin disease commonly affects adolescents and young adults, especially in warm and humid climates. The yeast is thought to feed on skin oils (lipids), as well as dead skin cells. Infections are more common in people who have seborrheic dermatitis, dandruff, and hyperhidrosis.<ref name="Weedon, D 2002"/>
ReferencesEdit
External linksEdit
Template:Diseases of the skin and appendages by morphology Template:Mycoses Template:Medical resources Template:Authority control