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TINEA VERSICOLOR

(PITYRIASIS VERSICOLOR)

DERMATOLOGY LECTURE NOTES

Debabrata Bandyopadhyay,  Associate Professor & Head, Dept. of Dermatology
R. G. Kar Medical College & Hospitals, Calcutta , INDIA

 


Tinea versicolor (also called pityriasis versicolor) is a mild, chronic, superficial fungal infection of the skin caused by Malassezia furfur. Tinea versicolor (TV) is characterized by hypopigmented or hyperpigmented, finely scaly, coalescing macules. The disease is usually asymptomatic and it typically involves the upper trunk particularly in young individuals living in warm, humid environment. There appears to be individual variations in susceptibility to the infection and the disease typically pursues a chronic and relapsing course.
 

CAUSE AND PATHOGENESIS:

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Tinea versicolor is caused by Malassezia furfur, a dimorphic, lipophilic fungus. The yeast phase of the organism was previously classified as Pityrosporum orbiculare and P.ovale but they are now reclassified as being the same species as M furfur.

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M. furfur is a member of the normal skin flora of  human beings. Under certain circumstances, the commensal yeast transforms into the filamentous pathogenic form.

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Production of disease is related to genetic predisposition, a hot and humid climate, steroid therapy, Cushing’s disease, pregnancy and malnutrition.

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The infection leads to a slightly increased epidermal turnover time resulting in visible scaling. Production of dicarboxylic acids like azelaic acid causes inhibition of tyrosine kinase resulting in hypopigmentation of the involved skin. Induction of enlargement in the size of the epidermal melanosomes is associated with the hyperpigmentation of the lesions.

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M. furfur is considered to be a contributory factor in the causation of other diseases like seborrheic dermatitis, pityrosporum folliculitis, and confluent and reticulated papillomatosis as well as some cases of atopic dermatitis.

CLINICAL FEATURES:

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Tinea versicolor affects both sexes equally.

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Typically adolescents and young adults are involved; childhood cases are more commonly seen in warm and humid climates.

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The disease is usually asymptomatic, the patients presenting with the cosmetic blemish. Some patients may complain of mild pruritus or irritation.

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The typical lesions of TV consist of hypopigmented to brownish, well-defined, small, round to oval macules with fine, powdery scales on their surface.

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A follicular localization with coalescence to produce larger, irregularly shaped patches is characteristic.

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The lesions are typically located on the upper back and chest, spreading to the adjacent areas of the arms and neck. Facial lesions are commonly seen during childhood. Less commonly, other areas of the skin may also be involved.

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Tinea versicolor may rarely be localized predominantly on the flexural areas like the axillae, groins and limb flexures, causing difficulty in differentiating from seborrheic dermatitis or erythrasma.

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Rarely, a follicular, itchy rash on the trunk and limbs may be caused by the fungus (pityrosporum folliculitis)

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DIFFERENTIAL DIAGNOSIS:

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Pityriasis alba

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Pityriasis rosea

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Seborrheic dermatitis

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Erythrasma

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Vitiligo

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Leprosy

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Syphilis

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Post-inflammatory hypopigmentation

DIAGNOSIS:

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In most cases, the clinical feature is sufficiently distinctive to permit a diagnosis.

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Indistinct or doubtful lesions may be made readily visible by Wood’s lamp examination which typically shows a yellowish fluorescence of the hypopigmented patches.

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Examination of skin scraping soaked in 10% potassium hydroxide helps microscopic visualization of the fungi that appear as short, thick hyphae with a large number of variously-sized spores (spaghetti and meat-ball appearance)

TREATMENT:

M. furfur is readily killed by almost all topical and systemic antifungals but since the organism is part of the normal flora on human skin, it is impossible to eradicate it permanently. As a consequence, relapse tends to occur sooner or later in predisposed individuals. Periodic suppressive medication may be tried to prevent relapse. It is also important to emphasize to the patients that the hypopigmentation usually persists for a variable period of time after successful antifungal therapy. 

TOPICAL THERAPY

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Selenium sulphide 2.5% in a detergent base (Selsun) is a very effective topical medication. Several recommendations for the mode of application and duration of therapy exists. Daily overnight application for a few days followed by few  weekly applications works very well. It should not be applied to the face or scrotum for severe irritation may ensue. 

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Zink pyrithione in shampoo base applied as above is also effective.

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Azole antifungals ( miconazole, clotrimazole, econazole, oxiconazole, bifonazole, ketoconazole etc.) is applied twice a day for a few weeks to achieve cure.  

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Terbinafine and ciclopirox olamine may also be used in the same way.

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Other alternatives include:

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Sodium thiosulphate lotion 20%

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Propylene glycol 50% in water

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Tretinoin cream

SYSTEMIC THERAPY

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In extensive involvement, where topical therapy may be impractical., systemic antifungals may be tried.

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Ketoconazole 400 mg single dose repeated monthly for a few months, is a very effective systemic treatment of TV 

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Fluconazole 450 mg single dose is somewhat less effective.

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Itraconazole 200 mg daily for five days is an effective regimen.

 

COURSE AND PROGNOSIS

Tinea versicolor is a mild and benign condition causing no more discomfort than occasional pruritus in some patients and embarrassment due to cosmetic reasons. Even after successful treatment the condition usually relapses and it is best to treat each episode anew. Some patients may prefer not to be treated at all.

 
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