Hypopigmented lesions Flashcards
What is vitiligo?
De-pigmentation of broad areas on the skin
What is the most currently believed etiology of vitiligo?
autoimmune
Onset age of vitiligo?
10-30yo
Onset of vitiligo usually occurs after what events?
Stress
Sun exposure
injury
What diseases are associated with vitiligo?
Thyroid idsease is common in these patients (except thyroid carcinoma)
DM, addison’s dz have slight increases in vitiligo
What is the histopathologic feature of vitiligo?
no melanocytes present in the involved skin
What causes pityriasis versicolor?
Fungus (Malassezia furfur) found on normal skin
What are risk factors of pityriasis versicolor?
Genetic predisposition
warm, humid environments
immunosuppression
malnutrition
Cushing’s dz
All the above may convert saprophytic fungus to morphologic form
When is pityriasis versicolor more obvious?
More obvious when pt is tain in the summer
What is the clinical appearance of pityriasis versicolor lesions?
Scaly skin macules
Affected area may be hypopigmented or hyperpigmented
What may cause the hypopigmentation of pityriasis versicolor lesions?
May be due to tyrosinase or inhibition of an enzyme in the melanin synthesis pathway
What may cause the hyperpigmentation of pityriasis versicolor lesions?
can result when the fungus induces melanosome enlargement
What is the histopathologic feature of pityriasis versicolor?
short, cigar-butt hyphae are present in diseased state.
Spaghetti and meatball sign of tinea (KOH finding of spores with short mycelium)
How is the diagnosis of pityriasis versicolor confirmed?
KOH examination
Scarpe stratum corneum onto glass slide, add KOH, stain for fungus, and use microscope
Tx for pityriasis versicolor?
Oral therapy is preferred (itraconazole and fluconazole)
Low rate of recurrence
