Screening for tinea unguium by thermography in older adults with subungual hyperkeratosis

Beyond visual inspection: The value of infrared thermography in skin diseases, a scoping review

Although warmth is a key sign of inflammatory skin lesions, an objective assessment and follow-up of the temperature changes are rarely done in dermatology. The recent availability of accurate, sensitive and cost-effective thermography devices has made the implementation of thermography in clinical settings feasible. The aim of this scoping review is to summarize the evidence around the value and pitfalls of infrared thermography (IRT) when used in the dermatology clinic. A systematic literature search was done for original articles using IRT in skin disorders. The results concerning the potential of IRT for diagnosis, severity staging and monitoring of skin diseases were collected. The data on the sensitivity and specificity of IRT were extracted. Numerous studies have investigated IRT in various skin diseases, revealing its significant value in wound management, skin infections (e.g. cellulitis), vascular abnormalities and deep skin inflammation (e.g. hidradenitis suppurativa). For other dermatological applications such as the interpretation of intradermal and patch allergy testing, hyper-/anhidrosis, erythromelalgia, cold urticaria and lymph node metastases more complex calculations, provocation tests or active cooling procedures are required. Dermatologists should be aware of a learning curve of IRT and recognize factors contributing to false positive and false negative results. Nonetheless, enough evidence is available to recommend IRT as a supplement to the clinical evaluation for the diagnosis, severity and follow-up of several skin diseases.

Evaluation of Thermography as a Diagnostic Technique in Asymptomatic or Incipient Onychomycosis

Onychomycosis is usually diagnosed symptomatically due to the very clear signs caused by the fungus on the nail surface and structure, although the growth of the infecting agent must also be verified by culture in an enriched medium. This procedure is normally lengthy (four weeks), and samples can be contaminated, delaying the prescription of appropriate and effective treatment. Only one previous study has addressed the possibility of using thermography as a diagnostic method for onychomycosis in older people (31-70 years). The present study confirms this use but in individuals aged 18-31 years with incipient mycosis and no pathological signs. Using an FLIR E60 BX camera in a study with 214 samples, we found that men had more onychomycosis than women. We observed a relation between the presence of infection and nail temperature, with a higher temperature in yeast infections (+1 °C) and a lower temperature in dermatophyte infections (-2 °C). A higher temperature by almost 1 °C was also observed in older participants. Thermography can be viewed as a new diagnostic method in asymptomatic or incipient onychomycosis, providing the thermographic camera is sufficiently sensitive and the appropriate procedure is followed, although fungal culture is always necessary to confirm recovery after treatment.

Evaluation of skin using infrared thermal imaging for dermatology and aesthetic applications

INTRODUCTION

The use of thermography in the medical field has been experiencing a renaissance due to advances in the infrared thermographic imaging technology, which improves thermographic equipment and promises cost saving and increased safety. Dermatology is one of the most promising fields of application among the medical areas with potential for the use of thermography.

OBJECTIVE

To review the findings on this subject and to describe the use of such technique for dermatology and aesthetic applications.

METHODS

A bibliographic survey was carried out, selecting relevant publications and guidelines, focused on monitoring medical diagnostic applications and benefits of thermography for dermatology, inflammatory skin diseases, and aesthetic applications.

RESULTS

Inflammatory skin diseases lead to changes of the IRT image. A quantification of treatment effects and monitoring changes on skin can be possible by repeated measurements over time.

CONCLUSION

Infrared imaging is a noninvasive, powerful tool in the diagnosis and clinical management of skin conditions and monitoring of aesthetic procedures.

Characterization of Baseline Temperature Characteristics Using Thermography in The Clinical Setting

BACKGROUND

Thermography is a diagnostic method based on the ability to record infrared radiation emitted by the skin and is unique in its ability to accurately show physiological and/or pathological cutaneous temperature changes in a non-invasive way. This method can be used to indirectly assess changes or impairments in cutaneous perfusion. Significant technological advancements have allowed thermography to be more commonly utilized by clinicians, yet a basic consensus of patient characteristics that may affect temperature recordings is not established.

MATERIALS AND METHODS

We evaluated cutaneous temperature in a cohort of outpatients to understand what factors, including tobacco use and other high-risk characteristics, contribute to cutaneous tissue perfusion as measured by thermography. Participants were prospectively enrolled if they were a combustible cigarette smoker, an electronic cigarette (e-cigarette) user, or a never smoker. Standardized thermographic images of the subject's facial profiles, forearms, and calves were taken and demographic characteristics, medical comorbidities, and tobacco product use were assessed. These variables were statistically tested for associations with temperature at each anatomic site.

RESULTS

We found that gender had a significant effect on thermographic temperature that differed by anatomic site, and we found a lack of significant difference in thermographic temperature by race. Our regression analysis did not support significant differences in thermographic temperatures across smoking groups, while there was a trend for decreased perfusion in smokers relative to non-smokers and e-cigarette users relative to non-smokers.

CONCLUSION

Thermographic imaging is a useful tool for clinical and research use with consideration of sex and other perfusion-affecting characteristics.

Examining the accuracy of visual diagnosis of tinea pedis and tinea unguium in aged care facilities

OBJECTIVE

The aim of this study was to examine the accuracy of visual diagnosis of tinea pedis (Athlete's foot) and tinea unguium (fungal nail infection), as well as to provide information on skin abnormalities that could help identify these diseases in aged care facilities (long-term care facilities (LTCFs) and nursing homes).

METHOD

A multicentre, cross-sectional observational study was conducted in a LTCF and two nursing homes. A dermatologist observed the skin abnormalities in the participants' interdigital and plantar areas, to screen for tinea pedis, and in the participants' toenails, to screen for tinea unguium. If abnormalities were noted, samples such as scales or toenails were collected and examined using direct microscopy. The accuracy of the macroscopic observation for each skin abnormality was examined.

RESULTS

A total of 173 residents were recruited. The accuracy of clinical diagnosis using macroscopic observation was relatively low. The sensitivities and specificities for clinical diagnosis were 0.37 and 0.95 for tinea pedis in the interdigital areas, 0.47 and 0.94 for tinea pedis in the plantar areas, and 0.80 and 0.61 for tinea unguium in toenails, respectively. Scales in the plantar areas and discoloration of the toenails were more frequently observed in residents with tinea pedis and tinea unguium than in those without them.

CONCLUSION

Several skin abnormalities were observed in the residents recruited in this study, but there was insufficient correlation with tinea pedis and tinea unguium to be used for screening.

Use of smartphone attached mobile thermography assessing subclinical inflammation: a pilot study

OBJECTIVE

To verify the reliability and validity of FLIR ONE, a device connected to a smartphone, for the assessment of inflammation based on relative temperature increase compared with the thermography routinely used in pressure ulcer (PU) and diabetic foot assessment.

METHOD

Participants in this pilot cross-sectional observational study were recruited from the patients in the PU team rounds and the diabetic foot outpatient clinic at the university hospital in January 2015. Cohen's kappa coefficient with its 95% confidence intervals was used to evaluate the criterion-related validity and inter- and intra-rater reliability for the thermal imaging assessment. For assessing criterion-related validity, a hand-held high-end infrared thermography device was used to provide reference data. Comparison of thermal images between the smartphone-connected device and the hand-held device was performed with both a 'predetermined range' and an 'automatically-set range.' For assessing inter-rater reliability, two assessors evaluated the thermal images taken by the mobile thermography. For assessing intra-rater reliability, one assessor evaluated the thermal images twice. The thermal images were shown to the assessors at random.

RESULTS

Among 16 thermal images obtained from eight patients, kappa coefficients for each value were as follows: for the predetermined range and automatically-set range, respectively, the criterion-related validity was 1.00 (95% confidence interval 1.00-1.00) and 1.00 (95% confidence interval 1.00-1.00); the inter-rater reliability was 1.00 (95% confidence interval 1.00-1.00) and 1.00 (95% confidence interval 1.00-1.00); and the intra-rater reliability was 1.00 (95% confidence interval 1.00-1.00) and 1.00 (95% confidence interval 1.00-1.00).

CONCLUSION

This pilot study suggests that FLIR ONE can work as an alternative device for assessing subclinical inflammation in PUs and the diabetic foot in clinical settings. Our results may facilitate clinicians in accepting the routine use of thermal imaging assessment at the patients' bedside.