Pruritic Macules

Nathan G. Miller, DO, LT, MC
Volume 55 - Issue 10 - October 2015

A 21-year-old white male presented to our clinic with a mildly pruritic rash that had been present for the last 2 to 3 years. Initially the rash was only on his trunk (Figure 1) but in the last 5 to 6 months, it has spread to his upper arms (Figure 2). The patient denies pain, vesicles, crust, and exudate. He had no fever or malaise. The rash is worse in summer months. 

History. His past medical history is unremarkable. 

Physical examination. Multiple hypopigmented and hyperpigmented macules are noted. The entire abdomen and axillae are involved. Hyperpigmented macules with fine scale scattered throughout are also present on the flexor surfaces of his upper extremities. 

Discussion. Tinea versicolor or pityriasis versicolor is a superficial fungal infection caused by the yeast species Malassezia. It presents with macules of various pigmentation, thus the term versicolor. Fine scale is often present. 

Pruritus is variable among patients. The most commonly involved sites are the trunk and upper extremities; although not common, cases have also been reported in the groin area, palms, and soles.1,2 

Tinea versicolor occurs more frequently in tropical climates. All age groups can be affected but the incidence is highest among adolescents and young adults.3 

In one study, tinea versicolor was found to disrupt the barrier function of the skin.4 Diagnosis is usually clinical. Potassium hydroxide preparation will show the classic “spaghetti and meatballs” and may be used to confirm the diagnosis. 

Differential diagnosis includes pityriasis rosea, vitiligo, and seborrheic dermatitis.5 

Treatment. Topical antifungals (eg, ketoconazole) are first-line therapies. Oral antifungals may also be used for widespread disease or resistant cases. Griseofulvin and oral terbinafine are not effective.5,6 A single 400 mg dose of fluconazole appears to be effective.7 Because recurrence is common, systemic or topical therapy may be used to prevent recurrence. Topical selenium sulfide 2.5% or ketoconazole 2% shampoo applied once a month for 10 minutes is sufficient to prevent recurrence.6,7

References:

1.William, JD, Berger TG, Elston, DM. Andrews' Diseases of the Skin Clinical Dermatology. 11th ed. Philadelphia, PA: Elsevier Inc; 2011:287-321. 

2.Varada S, Dabade T, Loo DS. Uncommon presentations of tinea versicolor. Dermatol Pract Concept. 2014;4(3);93-96. 

3.Gupta AK, Batra R, Bluhm R, et al. Pityriasis versicolor. Dermatol Clin. 2003;21(3);413-429, v-vi. 

4.Lee WJ, Kim JY, Song CH, et al. Disruption of barrier function in dermatophytosis and pityriasis versicolor. J Dermatol. 2011;
38(11):1049-1053. 

5.Wolff K, Saavedra A, Johnson RA. Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology. 5th ed. New York, NY: McGraw-Hill; 2005:730. 

6.Habif, TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 5th ed. Philadelphia, PA: Elsevier, Inc; 2009:537-540. 

7.Dehghan M, Akbari N, Alborzi N, et al. Single-dose oral fluconazole versus topical clotrimazole in patients with pityriasis versicolor: a double-blind randomized controlled trial. J Dermatol. 2010;
37(8):699-702.