Hypopigmented Macules and Patches - Clinical Advisor

Hypopigmented Macules and Patches

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A 30-year-old man presents to the clinic with a mildly itchy rash on his upper back and upper arms for the past week following a trip to the beach, during which time his skin became tanned from exposure to the sun. He is taking antihistamines. On examination, faint hypopigmented macules and patches with areas of fine scale are noted. Some of the lesions coalesce to form irregularly shaped patches. The patient denies pain but finds the lesions unsightly.

Tinea versicolor, also known as pityriasis versicolor, is a benign, chronic discoloration of the skin caused by the proliferation of yeast. Malassezia furfur, previously known as Pityrosporum, is the dimorphic, lipophilic fungus that causes tinea versicolor.1 In 1853, Robin described...

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Tinea versicolor, also known as pityriasis versicolor, is a benign, chronic discoloration of the skin caused by the proliferation of yeast. Malassezia furfur, previously known as Pityrosporum, is the dimorphic, lipophilic fungus that causes tinea versicolor.1 In 1853, Robin described the first Malassezia species.2,3 M furfur is a normal component of the skin flora that may opportunistically convert from the yeast to the mycelial form that invades the stratum corneum in tinea versicolor.4 Tinea versicolor occurs more frequently in hot, humid areas and tends to affect the skin of the face, arms, chest, and back. Adolescents and young adults are most commonly affected. Tinea versicolor is primarily a cosmetic concern but when pruritic can affect quality of life.2,5

Although the etiology of tinea versicolor appears to be multifactorial, genetics may predispose some individuals to developing these skin lesions. Adolescents and young adults more frequently develop tinea versicolor because increased sex hormones stimulate sebum production. In contrast, children less frequently experience tinea versicolor; when they do, it is more commonly found on the face. Other suspected contributing factors include the application of oils, creams, and cosmetics, which provide lipid nourishment for Malassezia. Tinea versicolor is associated with hyperhidrosis, exposure to sunlight, and oral contraceptive use, but it is not linked to poor hygiene.1,5 Immunocompromised individuals are at higher risk for tinea versicolor.4

Tinea versicolor typically presents as well-demarcated hypopigmented, hyperpigmented, or salmon-colored patches, commonly on the back and chest. The lesions differ widely in color, hence the term “versicolor”.1 Oftentimes, a single herald patch precedes the development of multiple smaller lesions that may coalesce into larger patches. Upon scraping, a fine scale is visible, and some patients complain of mild pruritus.1,2,6

The diagnosis of tinea versicolor is made clinically but can be confirmed with a potassium hydroxide (KOH) mount of scrapings. Scales slough off in characteristic sheets with the use of a glass slide or scalpel blade.6 Light microscopy of scrapings will reveal hyphae and round budding cells with a “spaghetti-and-meatball” appearance.2,5 Wood lamp examination reveals yellow to yellow-green fluorescence of tinea versicolor patches but is not preferred due to decreased sensitivity. A skin biopsy of tinea versicolor is characterized by lymphocytes around the dermal vasculature, mild epidermal hyperkeratosis, and acanthosis; however, it is rarely required to confirm diagnosis.4,5

Differential diagnoses of tinea versicolor include psoriasis, seborrheic dermatitis, pityriasis rosea, mycosis fungoides, secondary syphilis, pityriasis alba, erythrasma, and vitiligo. Seborrheic dermatitis tends to present with a thicker scale, usually on the scalp and face. Results from the KOH examination eliminate pityriasis rosea, pityriasis alba, secondary syphilis, and mycosis fungoides from the differential. Vitiligo presents with completely depigmented macules and patches as opposed to hypopigmented lesions. Erythrasma will fluoresce coral-red on Wood lamp illumination rather than the characteristic yellow-green of tinea versicolor.1,4,5

Treatment of tinea versicolor with topical and oral antifungals is usually successful. Topical antifungals, such as ketoconazole, are first-line therapy due to their targeted activity against Malassezia. Selenium sulfide and zinc pyrithione shampoos act by removing the stratum corneum and are also effective with a shorter required duration of therapy than ketoconazole antifungals.2 One to 3 applications of 2% ketoconazole can be sufficient for treatment.7 Topical treatment is less expensive than systemic treatment; however, application to the back may be difficult for some patients, and topical antifungal shampoos must be applied for extended periods of time before rinsing. Oral therapies are indicated for patients for whom topical therapy is ineffective or those who experience recurrent or widespread tinea versicolor. Oral fluconazole can safely treat extensive or recurrent tinea versicolor. Drug interactions and liver function abnormalities have been reported with the use of oral antifungals.8 Patients using either oral or topical therapies should be advised that the scale quickly resolves after treatment of active infection but dyschromic areas may persist for months. The successful resolution of active infection can be confirmed by KOH examination. Patients who experience multiple recurrences of tinea versicolor should use monthly topical or oral prophylaxis, particularly during the summertime.2

The diagnosis of tinea versicolor in this case was confirmed via KOH examination, and treatment with topical ketoconazole was initiated. After treatment with 2% ketoconazole shampoo, the patient started to notice resolution of the rash. The discoloration completely faded within a few weeks.

Emily Burns, BA, is a medical student; Michelle Eugene Lee, BS, is a medical student; and Christopher Rizk, MD, is a dermatology fellow at Baylor College of Medicine, in Houston, Texas.

References

  1. Mendez-Tovar LJ. Pathogenesis of dermatophytosis and tinea versicolor. Clin Dermatol. 2010;28(2):185-189.
  2. Hudson A, Sturgeon A, Peiris A. Tinea versicolor. JAMA. 2018;320(13):1396.
  3. Robin C. Historie Naturelle des Vegeaux Parasites. Paris; Chez H. Bailliere; 1853:438.
  4. Gupta AK, Batra R, Bluhm R, Faergemann J. Pityriasis versicolor. Dermatol Clin. 2003;21(3):413-429.
  5. Sunenshine PJ, Schwartz RA, Janniger CK. Tinea versicolor. Int J Dermatol. 1998;37(9):648-655.
  6. Han A, Calcara DA, Stoecker WV, Daly J, Siegel DM, Shell A. Evoked scale sign of tinea versicolor. Arch Dermatol. 2009;145(9):1078.
  7. Lange DS, Richards HM, Guarnieri J, et al. Ketoconazole 2% shampoo in the treatment of tinea versicolor: a multicenter, randomized, double-blind, placebo-controlled trial. J Am Acad Dermatol. 1998;39(6):944-950.
  8. Hu SW, Bigby M. Pityriasis versicolor: a systematic review of interventions. Arch Dermatol. 2010;146(10):1132-1140.