Boy With Pruritic Rash on Both Cheeks
Alexander K. C. Leung, MD—Series Editor
University of Calgary
Stewart P. Adams, MD
University of Calgary
Benjamin Barankin, MD
Toronto Dermatology Centre
Leung AKC, Adams SP, Barankin B. Boy with pruritic rash on both cheeks. Consultant Pediatricians. 2013;12(1):22-25.
A 9-year-old boy presented with a pruritic, erythematous rash on his cheeks. He had been treated for 1 month with 0.1% betamethasone valerate cream. There was no associated fever or joint symptoms. His past health was unremarkable. All other family members were healthy and with no history of skin problems.
Erythematous and slightly scaly patches on both cheeks. Remaining examination findings unremarkable.
What’s Your Diagnosis?
Answer: Tinea Incognito
Tinea incognito refers to a dermatophytosis that has lost its typical morphological features because of the use of corticosteroids or calcineurin inhibitors.1,2 The term “tinea incognito” was coined in 1968 by Ive and Marks who described 14 cases of atypical dermatophytoses secondary to the use of corticosteroids.3
PATHOGENESIS AND EPIDEMIOLOGY
Normally, the dermatophytes that cause tinea faciei—Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton tonsurans, Microsporum cani,4,5 and rarely Microsporum gypseum6—can be eliminated from the stratum corneum by a cell-mediated immune response.7 It is believed that tinea incognito is caused by a corticosteroid/calcineurin inhibitor-modified response of the host to a fungal infection rather than a pharmacologic effect on the fungus.6
Corticosteroids mediate their anti-inflammatory effects through binding to a cytoplasmic glucocorticoid receptor in the target cells and forming complexes that enter the nucleus of the cell.8,9 Once inside the nucleus, the corticosteroid-receptor complex interacts with glucocorticoid-response elements and alters transcription of various proinflammatory genes, with resultant suppression of inflammatory cell lines and cytokines.10
Calcineurin inhibitors work by binding to a cytoplasmic immunophilin.9 The complex inhibits the activity of calcineurin to dephosphorylate the nuclear factor of activated T-cell, a transcription factor required to activate IL-2 gene transcription. Inhibition of IL-2 production blocks the activation of T helper cells and T regulatory cells, and the activation of natural killer cells and monocytes.11 The immune responses that stimulate inflammation are therefore down-regulated.
Corticosteroids/calcineurin inhibitors suppress the immune response mounted by the host and allow the fungus to proliferate easily.12 As a result, the inflammation and pruritus is inhibited, erythema and scaling are decreased, and the tinea may take on a bizarre appearance.2,12 Potent fluorinated corticosteroids seem most likely to produce tinea incognito.12,13 This is especially so when they are applied under occlusive dressings.4
Reports of tinea incognito are often sporadic. We list here the findings of a few large retrospective studies. In a study of 200 cases of tinea incognito (98 male and 102 female patients, with a mean age of 42 years) in Italy by Romano and colleagues,14 T rubrum and T mentagrophytes were most commonly isolated. In a study of 6325 subjects with suspected dermatophytoses in Iran by Ansar and colleagues,15 56 patients (29 male and 27 female patients, with a mean age of 32.6 years) had tinea incognito. The most common type of infection was tinea corporis (32.1%) followed by tinea faciei (26.8%). T mentagrophytes and T rubrum were isolated in 28.6% and 12.5% of cases, respectively. In another study involving children in Spain by del Boz and colleagues,1 54 cases of tinea incognito were identified. Of the 28 male and 26 female patients, 9 were between 1 and 3 years of age, 20 between 4 and 10 years, and 25 between 10 and 14 years. T mentagrophytes and T rubrum were isolated in 44.4% and 13% of cases, respectively. The most usual clinical forms were tinea corporis (46.3%) and tinea faciei (38.9%).
The clinical manifestations of tinea incognito are highly variable. The rash can be rosacea-like, eczema-like, or discoid lupus erythematosus–like, especially on the face; and impetigo-like or eczema-like on the trunk and limbs.14 The lesion can sometimes be pruritic and may be accompanied by a burning sensation.16
Tinea incognito should be suspected in a patient with any erythematous, scaly patch or plaque that fails to respond to treatment with corticosteroids or calcineurin inhibitors; this is especially the case when the rash is unilateral. The diagnosis can be confirmed by finding the fungal mycelium in the stratum corneum using a potassium hydroxide preparation of scrapings from the lesion.
Fungal culture from skin scrapings can also establish the diagnosis. Scrapings from scales at the edge of the lesion produce the best results. A skin biopsy at the edge of the lesion can also clarify the diagnosis, although this is seldom performed in children. Recently, it has been shown that in vivo reflectance confocal microscopy provides high-resolution and real-time imaging for the diagnosis of tinea incognito.17
Differential diagnosis includes atopic dermatitis, seborrheic dermatitis, cutaneous candidiasis, contact dermatitis, acne vulgaris, nummular eczema, granuloma annulare, discoid lupus erythematosus, lupus pernio, psoriasis, neurodermatitis, lichenoid dermatitis, impetigo, erythema annulare centrifugum, and polymorphous light eruption.2,12,14
Topical antifungal agents, such as miconazole, ketoconazole, econazole, naftifine, clotrimazole, ciclopirox olamine, and terbinafine, are the treatment of choice for tinea incognito.18 Adding 1% hydrocortisone powder to an antifungal cream may be warranted if the rash is very symptomatic. Oral antifungal agents, such as itraconazole, fluconazole, and terbinafine, can be considered for extensive lesions or lesions that are resistant to topical antifungal treatment.19
1. del Boz J, Crespo V, Rivas-Ruiz F, de Troya M. Tinea incognito in children: 54 cases. Mycoses. 2011;54(3):254-258.
2. Rallis E, Koumantaki-Mathioudaki E. Pimecrolimus induced tinea incognito masquerading as intertriginous psoriasis. Mycoses. 2008;51(1):71-73.
3. Ive FA, Marks R. Tinea incognito. Br Med J. 1968;3(5611):149-152.
4. Jacobs JA, Kolbach DN, Vermeulen AH, et al. Tinea incognito due to Trichophyton rubrum after local steroid therapy. Clin Infect Dis. 2001;33(12):E142-E144.
5. Leung AK, Robson WL. Tinea faciei. Can J CME. 2006;18(10):73.
6. Romano C, Asta F, Massai L. Tinea incognito due to Microsporum gypseum in three children. Pediatr Dermatol. 2000;17(1):41-44.
7. Crawford KM, Bostrom P, Russ B, Boyd J. Pimecrolimus-induced tinea incognito. Skinmed. 2004;3(6):352-353.
8. Almawi WY, Melemedjian OK. Molecular mechanisms of glucocorticoid antiproliferative effects: antagonism of transcription factors activity by glucocorticoid receptor. J Leukoc Biol. 2002;71(1):9-15.
9. Leung AK, Hon KL. Atopic Dermatitis: A Review for the Primary Care Physician. New York: Nova Science Publishers, Inc; 2012:1-113.
10. Alomar A, Berth-Jones J, Bos JD, et al. The role of topical calcineurin inhibitors in atopic dermatitis. Br J Dermatol. 2004;151(suppl 70):3-27.
11. Ricci G, Dondi A, Patrizi A, Masi M. Systemic therapy of atopic dermatitis in children. Drugs. 2009;69(3):297-306.
12. Sánchez-Castellanos ME, Mayorga-Rodriguez JA, Sandoval-Tress C, Hernández-Torres M. Tinea incognito due to Trichophyton mentagrophytes. Mycoses. 2007;50(1):85-87.
13. Kaštelan M, Massari LP, Brajac I. Tinea incognito due to Trichophyton rubrum—a case report. Coll Antropol. 2009;33(2):665-667.
14. Romano C, Maritati E, Gianni C. Tinea incognito in Italy: a 15-year survey. Mycoses. 2006;49(5):383-387.
15. Ansar A, Farshchian M, Nazeri H, Ghiasian SA. Clinico-epidemiological and mycological aspects of tinea incognito in Iran: a 16-year study. Med Mycol J. 2011;52(1):25-32.
16. Stassiy A, Khachemoune A. What is this psoriasiform plaque? JAAPA. 2011;24(7):15.
17. Turan E, Erdemir AT, Gurel MS, Yurt N. A new diagnostic technique for tinea incognito: in vivo reflectance confocal microscopy. Report of five cases. Skin Res Technol. 2012 June 7. doi:10.1111/j.1600-0846.2012.00615.x.
18. Lesniak R. Tinea incognito. Dermatol Nurs. 2008;20(5):403-404.
19. Lange M, Jasiel-Walikowska E, Nowicki R, Bykowska B. Tinea incognito due to Trichophyton mentagrophytes. Mycoses. 2010;53(5):455-457.