Melanonychia

Differential diagnosis of pigmented nail lesions

The diagnosis of pigmented nail lesions is a concern for both general practitioners and dermatologists, due to the possibility of indicating nail melanoma. The origin of the dark pigmentation can be either melanocytic or non-melanocytic (fungi, bacteria, or blood), and clinical evaluation alone may not be sufficient for differentiation, requiring additional exams. Onychoscopy provides valuable information prior to biopsy. The causes of nail pigmentation will be described to aid in the differential diagnosis.

Exposome Impact on Nail Health

Background

The nail unit is a complex system with various components, each serving distinct functions. The exposome, encompassing external and internal factors such as UV radiation, air pollution, dietary habits, and cosmetic product usage, substantially influences nail health and can lead to premature nail aging.

Summary

Internal and external exposomal factors can impact differently on nail health, inducing a variety of different clinical conditions. Effective therapeutic strategies exist, but a comprehensive understanding of how the exposome affects nails is lacking. This article aims to bridge this knowledge gap by exploring the relationship between the exposome and nail health, emphasizing it as a central focus of our analysis.

Key Messages

(1) The exposome, comprising various external and internal factors, may significantly influence nail health negatively, leading to premature nail aging. (2) Different nail conditions may arise due to the exposomal influence on nails. (3) Understanding the exposome's impact on nail health is crucial for developing solutions to mitigate negative effects and improve overall nail well-being.

Seven Plus One Steps to Assess Pigmented Nail Bands (Melanonychia Striata Longitudinalis)

Melanonychia striata longitudinalis might involve one or more fingers and/or toes and might result from several different causes, including benign and malignant tumors, trauma, infections, and activation of melanocytes that might be reactive or related to the pigmentary trait, drugs and some rare syndromes. This broad differential diagnosis renders the clinical assessment of melanonychia striata particularly challenging. Nail matrix melanoma is relatively rare, occurs almost always in adults involves more frequently the first toe or thumb. The most common nail unit cancer, squamous cell carcinoma / Bowen disease (SCC) of the nail matrix is seldom pigmented. Histopathologic examination remains the gold standard for melanoma and SCC diagnosis, but excisional or partial biopsies from the nail matrix require training and is not routinely performed by the majority of clinicians. Furthermore, the histopathologic evaluation of melanocytic lesions of the nail matrix is particularly challenging, since early melanoma has only bland histopathologic alterations. Dermatoscopy of the nail plate and its free edge significantly improves the clinical diagnosis, since specific patterns have been associated to each one of the causes of melanonychia. Based on knowledge generated and published in the last decades, we propose herein a stepwise diagnostic approach for melanonychia striata longitudinalis: 1) Hemorrhage first 2) Age matters 3) Number of nails matters 4) Free edge matters 5) Brown or gray? 6) Size matters 7) Regular or irregular and, finally, "follow back".

Reticular melanonychia: a dermoscopic clue for terra firma-forme dermatosis on the nails

Terra firma-forme dermatosis of the nail plate can mimic other causes of melanonychia such as nail infection and melanoma. We present the cases of two patients and describe the dermoscopic features of this entity, which is characterized by a band-like reticular pigmentation that we describe as ‘reticular melanonychia’.

Chronic Polymicrobial Infectious Melanonychia Striata

CASE

A 62-year-old man presented with a 10-year history of isolated melanonychia striata of his dominant thumb. Surgical biopsy ruled out subungual melanoma but revealed foreign plant material causing chronic infectious melanonychia from multiple pathogens, including Pseudomonas aeruginosa, Escherichia coli, and Candida spp. After removal of the nail plate and thorough debridement, the melanonychial streak resolved completely at 12 months of follow-up.

CONCLUSION

Bacterial infection is a rarely reported cause of melanonychia, and in addition to surgical pathologic specimens, intraoperative fungal and bacterial cultures should always be obtained for accurate diagnosis of melanonychia striata.

Disorders of hyperpigmentation. Part I. Pathogenesis and clinical features of common pigmentary disorders

Disorders of hyperpigmentation are common and, depending on the extent and location of involvement, can affect the quality of life and pose a significant psychologic burden for patients. Given the similarities in presentation of the various causes of hyperpigmentation, it is often difficult to elucidate the etiology of these conditions, which is important to guide management. Furthermore, certain disorders, such as lichen planus pigmentosus and ashy dermatosis, have similar clinical and/or histologic presentations, and their classification as distinct entities has been debated upon, leading to additional confusion. In this review, the authors selected commonly encountered disorders of hyperpigmentation of the skin, subdivided into epidermal, dermal, or mixed epidermal-dermal disorders based on the location of pigment deposition, along with disorders of hyperpigmentation of the mucosa and nails. Melanocytic nevi, genetic disorders, and systemic causes of hyperpigmentation were largely excluded and considered to be outside the scope of this review. We discussed the pathogenesis of hyperpigmentation as well as the clinical and histologic features of these conditions, along with challenges encountered in their diagnosis and classification. The second article in this 2-part continuing medical education series focuses on the medical and procedural treatments of hyperpigmentation.

Optimal diagnosis and management of common nail disorders

Nail conditions are not only aesthetic concerns, and nail changes may be a clue to an underlying systemic diseases or infection. Without timely treatment, nail diseases can continue to worsen and significantly impair performance of daily activities and reduce quality of life. Examination of the nails is essential at every medical visit, and may uncover important findings. Brittle nail syndrome, onychomycosis, paronychia, nail psoriasis, longitudinal melanonychia, Beau's lines, onychomadesis and retronychia are common nail disorders seen in clinical practice. These conditions stem from infectious, inflammatory, neoplastic and traumatic aetiologies. Though each nail condition presents with its own distinct characteristics, the clinical findings may overlap between different conditions, resulting in misdiagnosis and treatment delays. Patients can present with nail plate changes (e.g. hyperkeratosis, onycholysis, pitting), discolouration, pain and inflammation. The diagnostic work-up of nail disease should include a detailed history and clinical examination of all 20 nail units. Dermoscopy, diagnostic imaging and histopathologic and mycological analyses may be necessary for diagnosis. Nail findings concerning for malignancy should be promptly referred to a dermatologist for evaluation and biopsy. Nail disease management requires a targeted treatment approach. Treatments include topical and/or systemic medications, discontinuation of offending drugs or surgical intervention, depending on the condition. Patient education on proper nail care and techniques to minimize further damage to the affected nails is also important. This article serves to enhance familiarity of the most common nail disorders seen in clinical practice. It will highlight the key clinical manifestations, systematic approaches to diagnosis and treatment options for each nail condition to improve diagnosis and management of nail diseases, as well as patient outcomes.Key messagesNail disease is not only a cosmetic issue, as nail changes can indicate the presence of a serious underlying systemic disease, infection or malignancy.Nail pain and changes associated with NP are physically and emotionally distressing and may contribute to functional impairment and diminished quality of life.LM is a hallmark sign of subungual melanoma and this finding warrants further investigation to rule out malignancy.

An Observational Study of Cutaneous Manifestations in Patients on Chemo and Radiation Therapy for Internal Malignancies at Tertiary Care Center

CONTEXT

Chemotherapy and radiation therapy given to treat internal malignancies may cause cutaneous, hair, nail, and oral mucosal changes. The present study is an effort to know the pattern of cutaneous drug reactions with chemo and radiotherapy.

MATERIALS AND METHODS

Patients of internal malignancies with skin lesions attending the dermatology and oncology OPD/ward were recruited after taking their written consent in vernacular language. A detailed history of skin lesions, malignancies, and treatment was taken. Clinical examination was carried out. Relevant investigations and biopsy were carried out as and when required. Being a descriptive study, age group and gender-wise frequency and percentage were calculated for the treatment of malignancies and dermatosis.

RESULTS

The study included 150 patients with 28 different types of internal malignancies, of which 127 (84.66%) patients were treated, 45 (35.43%) treated exclusively with chemotherapy, 16 (12.59%) with exclusive radiation therapy, and 66 (51.96%) with combined chemo and radiation therapy. Total 111 (87.41%) patients received chemotherapy and 82 (64.56%) patients received radiation therapy. Most common internal malignancy was breast carcinoma in 43 (28.67%) cases. Most common chemotherapeutic agent given was paclitaxel to 33 (29.73%) patients. Most common dermatosis associated with exclusive chemotherapy was hand-foot syndrome in 7 (15.55%) cases and with exclusive radiation therapy was radiation dermatitis in 8 (50%) cases.

CONCLUSIONS

The study was useful in understanding various chemo and radiation therapy-associated dermatosis so that early interventions can be done to prevent further treatment-related adverse effects.

LIMITATION

Small sample size and inability of pinpointing a single drug as the side effect.

Transient neonatal hyperpigmentation of the proximal nail fold in a Chinese infant: a case report

Cutaneous alterations are common in neonates and usually occur in the first few days of life. Most of these are transient and benign, appearing as physiological responses to birth. Skin pigmentation disorders are considered transitory dermatoses of newborn infants. Nail pigmentation manifests as asymptomatic brown to bluish-black skin pigmentation over the fingers and toes in newborns. Hyperpigmentation of the distal phalanx of both hands and feet is commonly found in dark-skinned newborns, but it is rare in fair-skinned newborns and East Asian populations. We herein describe a Chinese infant with transient neonatal hyperpigmentation of the proximal nail fold.

A Traditional Chinese Herb Citri Reticulatae Pericarpium Induced Melanonychia

The common causes for melanonychia include melanoma, repetitive trauma, underlying systemic diseases, onychomycosis, pseudomonas infection and drugs. Drug-induced melanonychia usually affects numerous nails and appears as light brown to black pigmentation on the deck or nail bed with longitudinal, transverse or diffuse distribution. In previous cases, a number of chemotherapeutic agents such as azathioprine, bleomycin sulfate, cyclophosphamide, hydroxyurea and methotrexate were usually linked to melanonychia. Citri reticulatae pericarpium (CRP) is a traditional Chinese herb which is widely used in many foods and health care products in China. Up till now, there were no adverse reactions of CRP reported throughout the literature. Herein, we firstly reported a case of melanonychia in a 67-year-old man caused by CRP for external use.

Chemotherapy-induced asymmetrical melanonychia

Introduction: Chemotherapy may cause various nail damages, including chromonychia, melanonychia, onycholisis, and onychomadesis. Melanonychia is characterized by melanin-derived brown-to-black nail pigmentation. It may occur as a result of nail matrix melanocytic activation or melanocytic hyperplasia, and nail invasion by melanin-producing pathogens. Case report: We present a case of a patient who developed an extremely rare event of asymmetric melanonychia during systemic treatment of non-Hodgkin lymphoma. The melanonychia developed in dose-dependent manner after 500 mg of doxorubicin. One of the most incriminating agents for melanonychia development are doxorubicin and to a less extent cyclophosphamide. Our patient received both drugs as combined chemotherapy. After treatment completion, the phenomenon disappeared. An extremely unexpected event was skin melanoma occurrence. Conclusion: It has not been clarified yet whether this event was causally related to previous nail-related melanocyte activation or it was just a coincidence.

Nutrition and nail disease

The nail is a specialized keratinous skin appendage that is often overlooked, even though nail disorders comprise approximately 10% of all dermatologic conditions. We provide an overview on the basic anatomy of the nail and function of each structure. We examine the chemical profile, including the keratin and mineral composition, of the nail plate. Subsequently, nail manifestations are reviewed, as virtually every nutritional deficiency can affect nail growth in some manner. We focus on how each nutritional deficiency can affect the different anatomic structures of the nail unit. The terminology and the differential diagnoses of the many different nail plate and nail bed abnormalities are reviewed. Finally, we focus on the evidence behind nutrition-based treatments in the setting of several nail disorders.

Melanonychia - Clues for a Correct Diagnosis

Melanonychia represents a brown to black discoloration of the nail plate that may be induced by benign or malignant causes. Two main mechanisms are involved in the appearance of melanonychias, i.e., melanocytic activation and melanocytic hyperplasia. The distinction between the two can be made based on the medical history of the patient, the clinical picture, dermoscopy, and histopathological examination and is essential for the adequate management of the patient. We review the main causes of melanonychia, with emphasis on the clues to the diagnosis of subungual melanoma.

The color of skin: brown diseases of the skin, nails, and mucosa

Brown diseases comprise disorders leading to hyperpigmentation in skin and nails. Melasma is an acquired skin disorder that is characterized by brownish macules that typically occur on the face. Schamberg disease, also known as progressive pigmented purpura, is characterized by brown pigmentation with pepper spots on their edges. We summarize the epidemiology, pathogenesis, histologic features, and treatment choices for additional brown diseases, including melasma, pigmented purpuric dermatoses, postinflammatory hyperpigmentation, drug-induced hyperpigmentation, and pigmentations due to systemic or physiologic conditions.

Melanonychia: Etiology, Diagnosis, and Treatment

Melanonychia is a very worrisome entity for most patients. It is characterized by brownish black discoloration of nail plate and is a common cause of nail plate pigmentation. The aetiology of melanonychia ranges from more common benign causes to less common invasive and in situ melanomas. Melanonychia especially in a longitudinal band form can be due to both local and systemic causes. An understanding of the epidemiology, pathophysiology and clinical details is necessary for adequate patient care and counseling. It not only helps in the early recognition of melanoma but also prevents unnecessary invasive work up in cases with benign etiology. An early diagnosis of malignant lesion is the key to favourable outcome. Though there are no established guidelines or algorithms for evaluating melanonychia, a systematic stepwise approach has been suggested to arrive at a probable etiology. We, hereby, review the aetiology, clinical features, diagnostic modalities and management protocol for melanonychia.

The color of skin: black diseases of the skin, nails, and mucosa

Gradations in skin color are a consequence of differing amounts of melanin and their varying distribution. Although many darkly pigmented skin lesions are melanocytic and can be attributed to melanin content, the color of a black lesion can also be due to blood, necrotic tissue, or exogenous pigment. The source, pattern, and distribution of the color in black lesions usually offer important insight into its etiology. This contribution reviews conditions that can take on a black color, discussing the cause of the hue and any additional impact sun exposure may have.

Spectrum of cutaneous lupus erythematosus in South Africans with systemic lupus erythematosus

BACKGROUND

Cutaneous involvement is very common in systemic lupus erythematosus. We describe the prevalence and spectrum of lupus-specific (cutaneous lupus erythematosus) and non-specific cutaneous features amongst mostly black South Africans with systemic lupus erythematosus.

PATIENTS AND METHODS

A retrospective record review of 298 South Africans (262 blacks and 36 non-blacks) with systemic lupus erythematosus was carried out. Cutaneous features were classified according to the Gilliam and Sontheimer classification of cutaneous lupus.

RESULTS

Most (81.5%) patients were black African females. The mean (SD) age at diagnosis and follow-up duration were 35.0 (11.8) and 8.0 (5.9) years, respectively. Cutaneous lupus erythematosus was seen in 76.1% of patients, mainly chronic cutaneous lupus erythematosus with the discoid lupus erythematosus subtype seen in 52.1% of patients. Acute cutaneous lupus erythematosus was seen in 30.2% of patients and was more common in non-blacks than blacks (odds ratio = 3.8 (1.9-7.9)); localized acute cutaneous lupus erythematosus was more common than generalized acute cutaneous lupus erythematosus (odds ratio = 2.6 (1.6-4.4)). Non-specific cutaneous features occurred in 77.2%, with oral/nasal ulcers and Raynaud's phenomenon each occurring in approximately 40% of patients. Diffuse melanonychia at initial diagnosis was present in 37.4% of patients and was more common in blacks than non-blacks (odds ratio = 3.1 (1.3-7.3)). Acute cutaneous lupus erythematosus was associated with renal disease (odds ratio = 2.8 (1.6-4.7)) and chronic cutaneous lupus erythematosus with arthritis (odds ratio = 2.02 (1.24-3.29)). Diffuse melanonychia was associated with less renal disease and anti-dsDNA antibody positivity (odds ratio = 0.4 (0.3-0.7) and 0.4 (0.2-0.6), respectively) and significantly lower lupus severity index scores (mean (SD) = 5.99 (1.11) vs 6.56 (1.36) in patients with no melanonychia, p < 0.05)).

CONCLUSION

In this study of South Africans with systemic lupus erythematosus, the skin was the most commonly affected organ. In general, cutaneous lupus erythematosus was associated with less severe systemic disease. Acute cutaneous lupus erythematosus was less common in blacks, whereas discoid lupus erythematosus was more common than reported in Caucasians. Diffuse melanonychia was a distinctive finding and was associated with milder systemic disease.

Dermoscopy of the Month

Melanonychia refers to a brown or black coloration of the nail plate caused by numerous factors. Regarding the arrangement of pigmentation, we can differentiate between total melanonychia, when pigmentation involves the whole nail plate, or transverse or longitudinal melanonychia, when pigmentation involves the nail in a form of transverse or longitudinal band of pigmentation, respectively. Since longitudinal melanonychia can be a sign of numerous benign and malignant lesions, it often poses a diagnostic challenge for a dermatologist. Herein, we report a case of a 13-year-old girl who developed longitudinal melanonychia on multiple nails after receiving a therapy with azithromycin.

Transverse melanonychia in a child receiving chemotherapy

Transverse melanonychia is a rare finding often secondary to chemotherapy, orally ingested medications, or other iatrogenic interventions. A 19-month-old boy with hemophagocytic lymphohistiocytosis treated with biweekly etoposide and dexamethasone developed transverse bands of pigment in all toenail and fingernail units consistent with transverse melanonychia. We review the literature for reported cases of transverse melanonychia and summarize suspected etiologies.

Treatment of Digital Melanonychia with Atypia

BACKGROUND

Melanonychia of the digit is uncommon in the Caucasian population and is concerning because of potential malignant transformation. Several histologic changes occur before malignant transformation, including melanocytic atypia. The authors evaluated patients with melanonychia with melanocytic hyperplasia to determine the risk factors for malignant transformation.

METHODS

The authors retrospectively reviewed records for patients older than 18 years that underwent biopsy for melanonychia. They identified 22 patients with melanocytic hyperplasia with a median age of 61 years (interquartile range, 44 to 71 years). A bivariate analysis was performed to evaluate whether the degree of atypia was associated with malignant transformation and whether treatment choices by surgeons were based on melanocytic atypia.

RESULTS

Following biopsy, patients were followed for a median of 41.0 months (interquartile range, 4.8 to 100.6 months). Melanocytic atypia was present in nine patients and transformed into a malignancy in three: in two patients it became a melanoma in situ, and in one it became an acral lentiginous melanoma. Moderate-severe and severe melanocytic atypia was associated with malignant transformation. After initial biopsy, 14 patients were monitored (11 without atypia and three with atypia). One patient with slight atypia, two patients with moderate-severe atypia, and two patients with severe atypia underwent additional treatment. Patients with melanocytic hyperplasia without atypia were monitored more often (78.6 percent versus 21.4 percent).

CONCLUSIONS

Melanonychia presents a challenge to the hand surgeon, as some patients may be monitored and some should undergo additional resection. Patients with moderate-severe melanocytic atypia following biopsy should undergo resection, and those with mild to slight atypia can most often be monitored clinically.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Case Report: Dermoscopic features of oral lichen planus - the evolution of mucoscopy

Dermoscopy, a non-invasive technique for cutaneous diagnosis is being increasingly studied in various disorders of the skin, nails and scalp. However, it has been under-utilized for the diagnosis and characterization of mucosal disorders. The dermoscopic characterization of cutaneous lichen planus and its variants has been well documented with Wickham’s striae constituting the hallmark of the condition. However, the dermoscopic features of oral lichen planus with hand-held or videodermoscopy remain to be elucidated. We present the case of a young adult man who presented with asymptomatic white lacy lesions over a bluish-black background over the tongue, patchy hyperpigmentation of the buccal mucosae and gingivae, and longitudinal melanonychia involving some nails. History of intake of any drugs preceding the lesions, smoking, chewing of betel nut and dental implants was negative. Family history was non-contributory. There were no cutaneous lesions suggestive of lichen planus. Mucoscopy (dermoscopy of the mucosa, oral in this case) and onychoscopy were done followed by biopsy from the tongue that confirmed the diagnosis of lichen planus. Oral mucoscopy of the tongue revealed a tri-colored pattern with structureless veil-like grey-white areas (modified Wickham’s striae), well-demarcated red glossy erosions, and violaceous-to-brown clods. Additionally, vascular pattern of dotted and linear to curved vessels along the borders of leukoplakia-like areas and erosions were observed. Onychoscopy confirmed lichen planus-associated melanonychia. Dermoscopy also proved useful in conveniently ruling out other disorders typified by mucosal and nail pigmentation such as Laugier Hunziker syndrome and drug-induced changes. Although direct oral microscopy has been used in defining features of oral lichen planus, to the best of our knowledge this case is the first report on mucoscopy or dermoscopy of oral lichen planus

Sparfloxacin-induced nail pigmentation: A case of fixed drug eruption?

Sparfloxacin, a synthetic, second generation, broad spectrum aminodifluoroquinolone antibiotic, has excellent penetration into respiratory tissues and has good activity against Gram-positive, Gram-negative, and atypical bacteria. Although it is indicated for the treatment of adult community-acquired pneumonia and acute exacerbation of chronic bronchitis, its use has been limited by phototoxicity which is more common with it than with other quinolones. We report a case of a 20-year-old Nigerian woman who developed a diffuse blue-black nail pigmentation of thumb and big toe nails, 2 weeks after completing therapy with sparfloxacin, and a recurrence of the pigmentation in the same nails 1 year after taking the drug again. We think this is likely a case of subungual fixed drug eruption. We briefly discuss the causes and mechanisms of drug-induced nail pigmentation in general.

POSSIBLE NATURE OF THE RADIATION-INDUCED SIGNAL IN NAILS: HIGH-FIELD EPR, CONFIRMING CHEMICAL SYNTHESIS, AND QUANTUM CHEMICAL CALCULATIONS

Exposure of finger- and toe-nails to ionizing radiation generates an Electron Paramagnetic Resonance (EPR) signal whose intensity is dose dependent and stable at room temperature for several days. The dependency of the radiation-induced signal (RIS) on the received dose may be used as the basis for retrospective dosimetry of an individual's fortuitous exposure to ionizing radiation. Two radiation-induced signals, a quasi-stable (RIS2) and stable signal (RIS5), have been identified in nails irradiated up to a dose of 50 Gy. Using X-band EPR, both RIS signals exhibit a singlet line shape with a line width around 1.0 mT and an apparent g-value of 2.0044. In this work, we seek information on the exact chemical nature of the radiation-induced free radicals underlying the signal. This knowledge may provide insights into the reason for the discrepancy in the stabilities of the two RIS signals and help develop strategies for stabilizing the radicals in nails or devising methods for restoring the radicals after decay. In this work an analysis of high field (94 GHz and 240 GHz) EPR spectra of the RIS using quantum chemical calculations, the oxidation-reduction properties and the pH dependence of the signal intensities are used to show that spectroscopic and chemical properties of the RIS are consistent with a semiquinone-type radical underlying the RIS. It has been suggested that semiquinone radicals formed on trace amounts of melanin in nails are the basis for the RIS signals. However, based on the quantum chemical calculations and chemical properties of the RIS, it is likely that the radicals underlying this signal are generated from the radiolysis of L-3,4-dihydroxyphenylalanine (DOPA) amino acids in the keratin proteins. These DOPA amino acids are likely formed from the exogenous oxidation of tyrosine in keratin by the oxygen from the air prior to irradiation. We show that these DOPA amino acids can work as radical traps, capturing the highly reactive and unstable sulfur-based radicals and/or alkyl radicals generated during the radiation event and are converted to the more stable o-semiquinone anion-radicals. From this understanding of the oxidation-reduction properties of the RIS, it may be possible to regenerate the unstable RIS2 following its decay through treatment of nail clippings. However, the treatment used to recover the RIS2 also has the ability to recover an interfering, mechanically-induced signal (MIS) formed when the nail is clipped. Therefore, to use the recovered (regenerated) RIS2 to increase the detection limits and precision of the RIS measurements and, therefore, the dose estimates calculated from the RIS signal amplitudes, will require the application of methods to differentiate the RIS2 from the recovered MIS signal.

[Dark nail: clinical findings, diagnostics and therapy of melanonychia]

BACKGROUND

A dark colored pigmentation of nails can be due to a subungual malignant melanoma. There are, however, many other benign causes and this differentiation is an important challenge in dermatological practice.

PROBLEM

When should nail pigmentation be clarified by histological investigations?

MATERIAL AND METHODS

This article gives a survey of the literature on this topic and a review of own experiences with clinical case examples. The various causes of melanonychia are presented and criteria for the early recognition of melanoma of the nail matrix are formulated.

RESULTS

The width and depth of color of longitudinal melanonychia do not allow any conclusions on the dignity. If the nail striation is proximally broader than distally, this is evidence of a proliferative event. Confirmation of a subungual hemorrhage does not exclude a malignancy per se. Also detection of pigmentation due to fungi does not exclude the additional presence of a subungual melanoma. A systematic clinical analysis using clear criteria leads to a working diagnosis and suitable treatment.

CONCLUSION

An early and correct designation of nail pigmentation can avoid unnecessary nail interventions but can also be life saving.

Acquired melanonychia in chilean patients with essential thrombocythemia treated with hydroxyurea: a report of 7 clinical cases and review of the literature

Longitudinal melanonychia has been associated with a range of drugs, especially chemotherapeutic agents. We report 7 cases of melanonychia associated with the use of hydroxycarbamide for essential thrombocythemia. Of a patient population of 27, 7 (26%) developed melanonychia over a period of 2-7 years, and was not dose dependent. The high incidence of melanonychia in Chilean patients may be in part due to their Hispanic descent or to the high levels of UV radiation found in Santiago.