Tinea capitis (TC), a dermatophyte scalp and hair shaft infection, is an important public health concern. Confirmatory testing (eg, direct microscopy, fungal culture) before treatment is generally considered best practice because suspected TC has a broad differential diagnosis and treatment requires prolonged oral antifungal therapy.1,2 Since national data on TC epidemiology, testing, and treatment practices are lacking, our objectives were to calculate TC incidence and describe testing and treatment practices for a large cohort of commercially insured children in the United States.
We analyzed Merative MarketScan Commercial Database (https://www.merative.com/real-world-evidence), selecting patients aged <18 years with ≥1 outpatient visit during July 1, 2016 to December 31, 2020, continuous insurance enrollment during the 180 to 365 days surrounding the first outpatient visit, and no TC diagnosis on or in the 180 days before the first outpatient visit. We calculated 1-year TC incidence, stratifying by demographic features. We identified TC cases and TC-related diagnostic testing using International Classification of Diseases, 10th Revision, code B35.0 and Current Procedural Terminology codes. We compared diagnostic and treatment practices among specialties using χ2 tests (α = 0.05).
Among 3,929,156 patients, 1-year TC incidence per 10,000 person-years was 16.3 (95% CI, 15.9–16.7) (Table I). Incidence was highest among 5-year-olds (31.6; 95% CI, 29.1–34.0), males (20.9; 95% CI, 20.3–21.5), and Southern residents (22.5; 95% CI, 21.8–23.2).
Table I.
One-year incidence of tinea capitis among children aged <18 years—United States, July 1, 2016 to December 31, 2021
| Characteristic | n | Population at risk | Incidence (per 10,000 person-years) | 95% CI |
|---|---|---|---|---|
| Overall | 6391 | 3,929,156 | 16.3 | 15.9–16.7 |
| Age, y* | ||||
| <1 | 22 | 15,504 | 14.2 | 8.3–20.1 |
| 1 | 242 | 159,186 | 15.2 | 13.3–17.1 |
| 2 | 384 | 170,369 | 22.5 | 20.3–24.8 |
| 3 | 485 | 185,772 | 26.1 | 23.8–28.4 |
| 4 | 588 | 200,081 | 29.4 | 27.0–31.8 |
| 5 | 638 | 202,212 | 31.6 | 29.1–34.0 |
| 6 | 589 | 206,186 | 28.6 | 26.3–30.9 |
| 7 | 539 | 214,194 | 25.2 | 23.0–27.3 |
| 8 | 446 | 225,546 | 19.8 | 17.9–21.6 |
| 9 | 464 | 234,907 | 19.8 | 18.0–21.5 |
| 10 | 382 | 244,463 | 15.6 | 14.1–17.2 |
| 11 | 389 | 259,950 | 15.0 | 13.5–16.5 |
| 12 | 243 | 264,717 | 9.2 | 8.0–10.3 |
| 13 | 242 | 263,358 | 9.2 | 8.0–10.3 |
| 14 | 202 | 260,887 | 7.7 | 6.7–8.8 |
| 15 | 205 | 266,433 | 7.7 | 6.6–8.7 |
| 16 | 194 | 276,827 | 7.0 | 6.0–8.0 |
| 17 | 137 | 278,564 | 4.9 | 4.1–5.7 |
| Sex | ||||
| Male | 4177 | 1,998,956 | 20.9 | 20.3–21.5 |
| Female | 2214 | 1,930,200 | 11.5 | 11.0–11.9 |
| US census region of residence | ||||
| South | 3852 | 1,714,786 | 22.5 | 21.8–23.2 |
| Midwest | 1069 | 847,719 | 12.6 | 11.9–13.4 |
| Northeast | 921 | 662,445 | 13.9 | 13.0–14.8 |
| West | 512 | 682,985 | 7.5 | 6.8–8.1 |
| Unknown | 37 | 21,221 | 17.4 | 11.8–23.0 |
| Urban-rural status of residence | ||||
| Non-rural | 5750 | 3,498,945 | 16.4 | 16.0–16.9 |
| Rural | 608 | 413,537 | 14.7 | 13.5–15.9 |
| Unknown | 33 | 16,674 | 19.8 | 13.0–26.5 |
Patient age at the beginning of the 1-year follow-up period. Median age at time of diagnosis was 7 years (interquartile range: 5 to 11).
Most patients with TC were diagnosed by pediatricians (54.6%), followed by dermatologists (11.7%) and family practitioners (10.4%) (Table II). Confirmatory testing was infrequent (21.9%), and the most common tests were fungal culture (17.8%) and direct microscopy (9.7%). Testing was more frequent among patients diagnosed by dermatologists (51.0%) than by pediatricians (16.4%) or family practitioners (11.0%) (P <.01).
Table II.
Diagnostic and treatment practices for tinea capitis in a cohort of commercially insured children, by diagnosing specialty*
| Characteristic | Overall (N = 6391) | Pediatrician (n = 3487) | Dermatologist (n = 749) | Family practitioner (n = 662) | Unspecified or other (n = 1493) | P value |
|---|---|---|---|---|---|---|
| Diagnostic testing | 1399 (21.9) | 573 (16.4) | 382 (51.0) | 73 (11.0) | 371 (24.8) | <.01 |
| Fungal culture | 1139 (17.8) | 496 (14.2) | 289 (38.6) | 43 (6.5) | 311 (20.8) | |
| Direct microscopy | 617 (9.7) | 232 (6.7) | 184 (24.6) | 34 (5.1) | 167 (11.2) | |
| Antifungal susceptibility testing | 108 (1.7) | 42 (1.2) | 24 (3.2) | 10 (1.5) | 32 (2.1) | |
| Skin biopsy | 34 (0.5) | 3 (0.1) | 13 (1.7) | 2 (0.3) | 16 (1.1) | |
| Polymerase chain reaction | 15 (0.2) | 7 (0.2) | 2 (0.3) | 2 (0.3) | 4 (0.3) | |
| Any antifungal drug | 4853 (75.9) | 2789 (80.0) | 523 (69.8) | 499 (75.4) | 1042 (69.8) | <.01 |
| Oral | 3911 (61.2) | 2437 (69.9) | 392 (52.3) | 353 (53.3) | 729 (48.8) | <.01 |
| Griseofulvin | 3365 (52.7) | 2282 (65.4) | 253 (33.8) | 252 (38.1) | 578 (38.7) | |
| Terbinafine | 353 (5.5) | 88 (2.5) | 112 (15.0) | 57 (8.6) | 96 (6.4) | |
| Fluconazole | 208 (3.3) | 74 (2.1) | 30 (4.0) | 47 (7.1) | 57 (3.8) | |
| Itraconazole | 4 (0.1) | 1 (0.0) | 0 (0.0) | 0 (0.0) | 3 (0.2) | |
| Topical | 2290 (35.8) | 1169 (33.5) | 331 (44.2) | 237 (35.8) | 553 (37.0) | <.01 |
| Ketoconazole | 1818 (28.4) | 955 (27.4) | 260 (34.7) | 176 (26.6) | 427 (28.6) | |
| Clotrimazole | 232 (3.6) | 107 (3.1) | 11 (1.5) | 48 (7.3) | 66 (4.4) | |
| Selenium sulfide | 146 (2.3) | 91 (2.6) | 13 (1.7) | 13 (2.0) | 29 (1.9) | |
| Econazole | 98 (1.5) | 48 (1.4) | 20 (2.7) | 10 (1.5) | 20 (1.3) | |
| Other topical antifungal | 127 (2.0) | 26 (0.7) | 54 (7.2) | 12 (1.8) | 35 (2.3) | |
| Combination antifungal and corticosteroid creams | 95 (1.5) | 31 (0.9) | 7 (0.9) | 27 (4.1) | 30 (2.0) | <.01 |
| Oral therapy only | 2563 (40.1) | 1620 (46.5) | 192 (25.6) | 262 (39.6) | 489 (32.8) | <.01 |
| Topical therapy only | 942 (14.7) | 352 (10.1) | 131 (17.5) | 146 (22.1) | 313 (21.0) | <.01 |
| Received testing and oral antifungal therapy | 757 (11.8) | 376 (10.8) | 198 (26.4) | 46 (6.9) | 137 (9.2) | <.01 |
Data shown as no. (%). Patients could receive more than 1 type of diagnostic test and more than 1 type of treatment. Diagnostic tests were considered tinea capitis—related if they were documented within 90 days before to 0 to 7 days after the tinea capitis diagnosis date. Antifungal drug prescriptions were considered tinea capitiserelated if they were documented within 0 to 7 days after the incident tinea capitis visit date. Diagnostic tests were identified using the following Current Procedural Terminology codes: fungal culture (87101, 87102, 87106, 87107), direct microscopy (87210, 87220, 87206), antifungal susceptibility testing (87186), skin biopsy (11100, 11102, 11103, 11104, 11105, 11106, 11107), and polymerase chain reaction (87481, 87798, 87800, 87801).
Overall, 75.9% of patients were prescribed any antifungal, 61.2% were prescribed an oral antifungal (most frequently griseofulvin [52.7%]), and 14.7% were prescribed topical antifungal therapy alone. Patients prescribed topical therapy alone were more often diagnosed by family practitioners (22.1%) than by dermatologists (17.5%) or pediatricians (10.1%) (P <.01).
Most patients diagnosed with TC received no confirmatory laboratory testing, which is concerning because visual inspection alone of suspected cutaneous fungal infections can lead to diagnostic errors and unnecessary antifungal use.3,4 Low testing rates might be due to Clinical Laboratory Improvement Amendments restrictions, long turnaround times, and low reimbursement rates. Guidelines recommend against using topical antifungals alone, due to lack of hair shaft penetration.2 Since 38.8% of patients with TC were either prescribed topical treatment alone or not prescribed antifungals, there might be lack of knowledge about appropriate TC treatment, diagnostic uncertainty, and reluctance to prescribe systemic antifungals to children. The higher TC incidence among prepubescent and male children is consistent with previous studies.5
Study limitations include lack of information on race/ethnicity and non-commercial insurance types. Further, administrative data are subject to potential disease misclassification and undercoding, which might particularly affect reporting of diagnostic tests with low reimbursement rates (eg, direct microscopy). While dermatologists’ use of diagnostic testing for TC exceeded other specialties, our study highlights important opportunities across all specialties to increase testing and ensure effective treatment for children with TC.
Footnotes
Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the CDC.
Note: This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy (for example, 45 C.F.R. part 46, 21 C.F.R. part 56; 42 U.S.C. §241(d); 5 U.S.C. §552a; 44 U.S.C. §3501 et seq).
Conflicts of interest
Dr Lipner has served as a consultant for Hoth Therapeutics, BelleTorus Corporation, and Orthodermatologics. Dr Gold, Author Benedict, and Dr Dulski have no conflicts of interest to declare.
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