Clinico-onychoscopic correlation of chronic paronychia – A single-center observational cross-sectional study

INTRODUCTION

Nail disorders, whether primary or secondary to systemic diseases, account for approximately 10% of all dermatological conditions.^[1] The nail is capable of mounting only a limited number of reaction patterns to a large number of disorders. Therefore, simple visual inspection may not be helpful in diagnosing many conditions reliably. Onychoscopy is a noninvasive, rapid, and valuable interface between macroscopic and microscopic features, not only for diagnosis but also for assessing response to treatment and progression of disease, as subtle alterations can be easily missed by the naked eye.^[2] Onychoscopy refers to the examination of the nail unit, using either a hand-held or video-dermoscope.^[3] Both contact and non-contact methods of onychoscopy are used together with non-polarized and polarized light sources for better evaluation of the nail unit and act as a valuable aid not only in enhancing visible nail features but also in revealing cryptic features of diagnostic importance.^[4]

Paronychia refers to the inflammation of the nail folds, which can be acute (< 6 weeks duration) or chronic (> 6 weeks duration). Disruption of the protective barrier between the nail plate and the adjacent nail fold, preceded by infectious or non-infectious or eczematous etiologies, results in the development of paronychia.^[5] A PubMed-indexed search revealed few studies with onychoscopic findings of various nail disorders collectively.^[1,3,6-9] There is a paucity of data on the specific description of onychoscopic changes seen in paronychia. Our study primarily aimed at describing the clinico-onychoscopic findings in chronic paronychia and looking for any association with the severity of the disease.

MATERIAL AND METHODS

Patients clinically diagnosed as chronic paronychia involving all ages and either sex, who consented to participate in the study were included through a convenience sampling method. Concomitant systemic diseases and papulosquamous diseases affecting the nail unit and patients with a history of nail trauma or malignancy were excluded from our study. A written consent was taken for photography and the use of pictures for academic purposes. The study was approved by the institutional ethics committee.

All the patients attending the dermatology outpatient department diagnosed with chronic paronychia were subjected to onychoscopic examination. A clinical examination of the fingers and toes was done, along with grading of severity according to the chronic paronychia severity index scale proposed by Atis et al.^[10] [Table 1] and clinical photographs were taken. Onychoscopy was performed using DermLite DL4, with the digit kept lightly on a hard surface, avoiding any undue pressure by the patient or the examiner. For optimum evaluation of vasculature, the hand was kept at the level of the heart. The nail plate was thoroughly cleaned with spirit to remove debris, dirt, or external applications. Initially, a “dry onychoscopic examination” (without any interface medium) and then a “wet onychoscopic examination” (using an interface medium of ultrasound jelly) were done. All the onychoscopic photographs were collected. A potassium hydroxide (KOH) stain for fungal elements was done in all the patients. Gram’s stain and pus culture, and sensitivity were done wherever required, and treatment was advised accordingly.

RESULTS

A female preponderance (85%) was noted in our patients, most of whom were in the 3rd and 4th decade (82.5%) of life. Majority of the patients (77.5%) were home makers or house helps with frequent contact with water and detergents and more than 4 nail plate involvement (62.5%) was prevalent. The most common clinical finding noted was swelling and scaling of the proximal nail fold (90%), followed by proximal nail fold erythema (87.5%), destruction and scaling of the lateral nail fold (75%), yellowish-brown discoloration of the nail plate (62.5%), beau’s line (17.5%), and onychomadesis (12.5%) respectively. According to the chronic paronychia severity index scale proposed by Atis G et al.,10 the severity distribution of our patients was, grade 3 (score 11-14(severe)) in 15(37.55%) patients, grade 2 (score 6-10(moderate)) in 19(47.5%) patients and grade 1 (score 1-5(mild)) in 6(15%) patients respectively. The clinical presentation of scaling of proximal and lateral nail folds along with yellowish brown nail plate discoloration [Figure 1a] correlated onychoscopically with superficial white scales on nail fold [Figure 1b] and linear regular brown striations on nail plate [Figure 1c] respectively. Similarly, the nail fold erythema [Figure 2a] corresponded to reddish pin point dots [Figure 2b] under onychoscope. The clinico-onychoscopic correlation as described in table 2, was found to be statistically significant (p value < 0.05) for each variable. The onychoscopic findings of effacement of the cuticles and red dots on the nail bed were the most common findings noted in 33 patients each (82.5%) [Figure 2b], followed by proximal and lateral nail fold superficial white scaling seen in 30 patients (75%), linear regular brown striations [Figure 1b] in 26 patients (65%), and grooves in the proximal nail plate [Figure 1c] with loss of lateral nail fold and transverse brown bands seen in 5 patients each (12.5%). The onychoscopic finding of superficial white scaling was commonly seen in patients with mild disease rather than red dots on nail bed, linear brown striations, and effacement of cuticles, which were commonly seen in the severe form of the disease [Table 3]. KOH was negative for fungal elements in 70% of cases, with reddish pinpoint dots being the most common onychoscopic finding in KOH-negative patients. Effacement of the cuticles was the most common finding in KOH: Potassium hydroxide + occasional presence ++ moderate presence +++ frequent presence KOH-positive patients with secondary candidial colonization and linear regular brown striations were the most common onychoscopic finding in those with dermatophyte invasion of the nail plates, as seen in Table 4.

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Figure 1:

(a) Scaling of proximal and lateral nail folds along with destruction of cuticles and yellowish brown discoloration of nail plate, (b) Superficial white scaling on dry onychoscopy, (c) Linear regular brown striations on nail plate and destruction of the lateral nail fold on dry onychoscopy.

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Figure 2:

(a) Swelling and erythema of the proximal nail fold, (b) Reddish pinpoint dots on the proximal nail fold on dry onychoscopy.

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DISCUSSION

Paronychia refers to the inflammation of the tissue surrounding the nail plate and can be further categorized as acute and chronic based on the duration of symptoms. It is necessary to differentiate acute from chronic paronychia as both warrant different courses of management. Chronic paronychia is multifactorial in origin and generally involves multiple digits and presents with erythema, pain, and swelling of the perionychium. Onychoscopy plays a vital role in differentiating acute from chronic paronychia based on specific findings. The primary cause of this persistent inflammatory state appears to be occupational and environmental irritants, with secondary candidal colonization likely acting as a contributor to ongoing inflammation. The higher incidence of chronic paronychia in housewives and house helps in our study can be attributed to their frequent contact with water and irritants, as was also seen in the study by Rathod et al. ^[8] Most of our patients (47.5%) presented with a grade 2 severity score (6–10). The most common clinical findings in our study were swelling and scaling of the proximal nail fold (90%) and proximal nail fold erythema (87.5%). Sutaria et al.^[1] reported destruction of cuticles (83.33%), brownish discoloration of nails (66.67%), nail fold scaling (66.67%), onychomadesis (50%), and nail fold erythema (33.3%), and Varma et al.^[6] reported nail fold erythema and scaling (100%), destroyed cuticle (80%), transverse brown bands (60%), and chromonychia (40%). Rathod et al.^[8] found beau’s line (87.5%) and brownish discoloration of the nail plate (66.7%) to be the most common findings in their study. In a recent review on clinical and onychoscopic manifestations of inflammatory nail disorders, nail fold erythema and scaling, nailfold and plate hyperpigmentation, and changes in cuticle were reported in chronic paronychia.^[9] We found reddish pinpoint dots (82.5%) in patchy distribution corresponding to nail fold erythema in our patients, as also reported by Sutaria et al. (16.67%).^[1] In our study, the onychoscopic findings of red dots on nail bed, linear brown striations, and effacement of cuticles were commonly seen in the severe form of the disease. Effacement of the cuticles in patients with secondary candidal colonization and linear regular brown striations in those with KOH-proven dermatophyte invasion of the nail plates were encountered frequently in our study.

The linear brown striations on onychoscopy may be attributed to inflammatory damage to nail matrix and plate, fungal invasion, and pigment deposition, whereas the reddish pinpoint dots corresponding to nailfold erythema may be attributed to dilated capillaries.^[11]

CONCLUSION

The present study describes the onychoscopic findings along with a novel clinico-onychoscopic correlation model in chronic paronychia. The frequent findings of effacement of cuticles and linear regular brown striations in patients with KOH proven positivity for Candida and dermatophytic infections respectively seen in our study, may guide regarding the etiology and treatment modality in resource poor settings where KOH test is unavailable for confirmation, although it needs to be established in future studies with larger sample size. This easy, quick, non-invasive, and cost-effective tool of onychoscopy will help in making a quicker and more accurate diagnosis of chronic paronychia. Nail changes positively correlating with the severity of the disease can also be confirmed through onychoscopic examination. Hence, it is prudent to carry out onychoscopy routinely to allay diagnostic dilemmas, monitor disease progression, and grade disease severity. Above all, its photographic documentation is a boon with regard to ease of record keeping. The study is limited by a smaller number of participants, and future studies with a larger sample size are required for further confirmation of the findings.