Nail Diseases in Skin of Color: A Research Gap

Image Credit: © Andrey Popov - stock.adobe.com

Inflammatory nail diseases are common in clinical practice, significantly affecting patient morbidity and quality of life.¹ However, there remains a considerable gap in understanding these conditions, particularly among individuals with skin of color (SoC).² This lack of knowledge is most pronounced in the diagnosis and management of nail psoriasis (NP), a condition commonly associated with psoriatic arthritis (PsA).³ A delayed recognition of NP often leads to worsened patient outcomes, including prolonged time to diagnosis and more severe disease presentation, especially in darker skin tones.⁴ With this in mind, a recent systematic review aimed to synthesize the clinical and onychoscopic features of inflammatory nail disorders in individuals with SoC to enhance diagnostic accuracy and treatment outcomes.⁵

Study Methods

The systematic review, conducted in June 2024, searched PubMed and Medline for articles documenting clinical and onychoscopic features of inflammatory nail disorders in SoC, specifically those with Fitzpatrick skin phototypes IV–VI. A total of 60 studies were included, encompassing a diverse set of inflammatory nail disorders in 12,743 patient cases. These disorders ranged from NP and nail lichen planus (NLP) to paronychia, alopecia areata (AA), and atopic dermatitis (AD). Researchers stated the findings suggest that inflammatory nail diseases in SoC populations present unique diagnostic challenges due to differences in clinical and onychoscopic features, such as subtle erythema and hyperpigmentation, which can be mistaken for other conditions.

Results

Among the 16 inflammatory nail disorders identified, NP was the most common, affecting 93% of the patients included in the review. NP in individuals with SoC often presents with darker pigmentation, making traditional signs like erythema and pitting more difficult to detect. As a result, the review found patients with SoC are diagnosed nearly 3years later than their non-SoC counterparts. This delay can hinder the timely diagnosis of PsA, a condition for which NP is a diagnostic criterion. Similarly, researchers stated that other conditions, such as NLP, are often underrecognized due to the appearance of longitudinal melanonychia, a common finding in darker-skinned individuals. This reactive melanonychia, induced by inflammatory changes in the nail matrix, is less frequently observed in lighter skin tones, contributing to misdiagnosis and progression to irreversible nail damage.

The review also highlighted nail involvement in other inflammatory diseases like AA, AD, and PRP. AA-associated nail changes were observed in 2.58% of patients, with common findings including pitting and onychorrhexis. Nail changes in AD, which researchers noted affects patients with SoC more severely, were associated with trachyonychia and pitting. These features were strongly linked to higher disease severity, reflecting the greater burden of AD in these populations.

Other notable findings included the observation of nail lichen nitidus and trachyonychia, both of which presented with longitudinal ridging and onycholysis. The review noted these conditions are particularly challenging to diagnose in patients with SoC, as nail changes may be subtle and easily overlooked in routine clinical assessments. In addition, onychotillomania (nail-picking disorder), although rare, was documented in a small percentage of patients. This condition often leads to significant, irreversible damage to the nail unit and is frequently misdiagnosed due to its varied presentation and patient denial of nail manipulation.

Researchers also found that distinguishing acute and chronic paronychia in SoC populations requires heightened awareness, as erythema may not be as apparent. Nail fold discoloration or hyperpigmentation, along with changes in the cuticle, are critical clues for diagnosis in individuals with darker skin.

Limitations

Despite the comprehensive nature of the review, significant gaps were identified in the literature, particularly regarding the documentation of skin phototypes and visual evidence to classify SoC. Many of the studies relied on the country of origin of the patients rather than explicitly identifying skin type, highlighting the need for more consistent reporting of skin phototype in future research.

Conclusion

The systematic review emphasizes the unique clinical and onychoscopic features of inflammatory nail disorders in patients with SoC. Longitudinal melanonychia and nail plate discoloration are key diagnostic features that are more commonly seen in SoC populations than in lighter-skinned individuals. Onycholysis and subungual hyperkeratosis were predominant in NP cases, contrasting with erythematous findings seen in lighter skin types. The findings underscore the need for heightened awareness of these conditions in SoC populations to improve diagnosis and treatment, ultimately contributing to better health equity in dermatological care.

References

1. Fiocco Z, Kupf S, Patzak L, et al. Quality of life and psychopathology in lichen planus: A neglected disease burden. Acta Derm Venereol. 2021;101(12):adv00619. doi:10.2340/actadv.v101.442
2. Falotico JM, Lipner SR. Lack of skin of color images of nail conditions in dermatology textbooks. Int J Dermatol. 2023;62(1):e48-e50. doi:10.1111/ijd.16028
3. Chang MJ, Lee D, Desai AD, Lipner SR. Disparities in time to diagnosis and disease severity in skin of colour patients with nail psoriasis: A retrospective analysis. J EurAcad Dermatol Venereol. 2023. doi:10.1111/jdv.19110
4. Taylor W, Gladman D, Helliwell P, et al. Classification criteria for psoriatic arthritis: development of new criteria from a large international study. Arthritis Rheum. 2006;54(8):2665-2673. doi:10.1002/art.21972
5. Tordjman L, Thomas J, Tosti A, Morrison BW. Inflammatory nail disorders in skin of color: A systematic review of clinical and onychoscopic manifestations. Int J Dermatol. 2025. doi:10.1111/ijd.17680