Therapeutic implications of dermoscopic findings in acanthosis nigricans: A clinical and histopathological study

Review of facial acanthosis nigricans: Easy to diagnose and difficult to treat marker of hyperinsulinemia/metabolic syndrome

Facial acanthosis nigricans (FAN) is an increasingly discussed anatomical variation of acanthosis nigricans (AN). Its presentation as brown to black pigmentation with ill-defined blurred margins with varying degree of textural changes commonly over forehead, temporal, and malar regions of the face predominantly in dark-skinned individuals with a male predilection can be confused with other common facial melanoses. Its pathogenesis, clinical features, and management are in many ways similar to in the commonly described areas like neck and major flexural areas. Understanding of FAN has gained momentum in the past decade with studies highlighting its association with various metabolic abnormalities particularly insulin resistance and obesity. It is now being considered to be a cutaneous marker of metabolic syndrome. While there is uniformity in its clinical description, there appears to be scope for further in depth biochemical and histopathological studies to link the pigmentation, altered texture and microscopic changes in individuals presenting with FAN and hyperinsulinemia with or without other features of metabolic syndrome. It awaits a consensus on grading its severity and correlating it with histological features as patients often hesitate to be subjected to a biopsy of the face. This is a review of current literature pertaining to FAN. Newer clinical, dermoscopic, histopathological, and biochemical insights will help to understand this relatively new entity.

Assessment of serum chemerin levels in acanthosis nigricans: A case-control study

BACKGROUND

Acanthosis nigricans (AN) is an asymptomatic skin condition linked to several underlying systemic conditions. Chemerin is an adipokine that increases during inflammatory disorders such as metabolic syndrome (MetS).

AIMS

This case-control study investigates the link between AN and the underlying MetS and serum levels of chemerin in individuals with obesity.

PATIENTS/METHODS

Twenty-five adults with AN and obesity (body mass index [BMI] > 30 kg/m² ), 25 adults with obesity but no AN, and 25 healthy controls (BMI < 30 kg/m² ) had their lipid profiles and serum chemerin concentrations examined.

RESULTS

The neck (80.0%) and axilla (68.0%) were the most common sites of AN. In participants with obesity, either alone or with AN, serum chemerin concentrations were significantly higher than in the control group (p < 0.001). Participants with obesity and AN had significantly higher levels of cholesterol, triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), and serum chemerin levels (p < 0.001), and significantly lower high-density lipoprotein cholesterol (HDL-c) levels (p < 0.001) when compared to participants with obesity alone. All participants with obesity and AN (100%) and 88% of those with obesity alone had MetS. Logistic regression revealed that systolic blood pressure >130 mmHg, diastolic blood pressure >85 mmHg, waist circumference >90 cm, TG >150 mg/dl, HDL-c <45 mg/dl, fasting blood glucose >100 mg/dl, and serum chemerin >300 ng/ml were significant (p < 0.05) risk factors for AN.

CONCLUSIONS

Acanthosis nigricans is a non-invasive and reliable sign of the underlying MetS and increased serum chemerin levels among individuals with obesity.

Acanthosis Nigricans: An Updated Review

BACKGROUND

Early recognition of acanthosis nigricans is important because acanthosis nigricans can be a cutaneous manifestation of a variety of systemic disorders and, rarely, as a sign of internal malignancy.

OBJECTIVE

The purpose of this article is to familiarize pediatricians with the clinical manifestations, evaluation, diagnosis, and management of acanthosis nigricans.

METHODS

A search was conducted in November 2021in PubMed Clinical Queries using the key term "acanthosis nigricans". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Acanthosis nigricans is characterized by symmetric, hyperpigmented, and velvety plaques with ill-defined borders, typically involving intertriginous areas. Obesity is the most common cause of acanthosis nigricans which is increasingly observed in obese children and adolescents and can serve as a cutaneous marker of insulin resistance. Early recognition of acanthosis nigricans is important because acanthosis nigricans can also be a cutaneous manifestation of a variety of systemic disorders and, rarely, as a sign of internal malignancy. This may consist of weight reduction, discontinuation of causative drugs, treatment of underlying endocrinopathy, or treatment of an underlying malignancy. For patients with isolated acanthosis nigricans and for those whose underlying cause is not amenable to treatment, treatment of the lesion may be considered for cosmetic reasons. Topical retinoids, vitamin D analogs, chemical peels, and other keratolytics are often used for the treatment of localized lesions. Seldom, systemic therapy such as oral retinoids may be considered for extensive or generalized acanthosis nigricans and acanthosis nigricans unresponsive to topical therapy. Other uncommon treatment modalities include dermabrasion, laser therapy, and surgical removal.

CONCLUSION

Although acanthosis nigricans is treatable, a complete cure is difficult to achieve. The underlying cause should be treated, if possible, to resolve and prevent the recurrence of acanthosis nigricans. The diagnosis is mainly clinical, based on the characteristic appearance (symmetrically distributed, hyperpigmented, velvety, papillomatous, hyperkeratotic plaques with ill-defined borders) and the typical sites (intertriginous areas, flexural area, and skin folds) of the lesions. The diagnosis might be difficult for lesions that have atypical morphology or are in an unusual location. Clinicians should be familiar with the clinical signs, evaluation, diagnosis, and therapy of acanthosis nigricans because of the link between it and underlying diseases.

Skin anomalies in acromegalic patients (Review of the practical aspects)

Acromegaly is a hormonal disorder which occurs as the result of growth hormone (GH) and insulin growth factor 1 (IGF-1) over-secretion; both hormones are related to skin anomalies. The skin acts as a large endocrine organ, hosting GH receptors in every cell while IGF-1 receptors are expressed only in keratinocytes. This review is a literature review of skin anomalies found in acromegaly, either related to the disease itself or associated with related complications such as secondary diabetes mellitus, or involving associated conditions such as genetic syndromes. The following clinical points are mentioned as follows. Excessive skin and enlargement of soft tissue are due to glycosaminoglycan deposits, edema, and hyperhidrosis (mostly facial and acral). Acanthosis nigricans, a body fold dermatosis associated with insulin resistance, involves local or diffuse hyperkeratotic plaques with or without hyperpigmentation, caused by growth factors including GH/IGF-1. Other findings include cherry angiomas (due to the effects of lipid anomalies on small vessels); oily skin features with keratosis, epidermoid cysts, crochordons, pseudo-acanthosis nigricans; a potentially higher prevalence of varicose veins and psoriasis; low level of evidence for basal cell carcinoma, respective hidroadenitis suppurativa has been noted. In addition, complicated uncontrolled secondary diabetes mellitus (DM) may result in necrobiosis lipoidica diabeticorum, diabetic dermopathy, skin bacterial infections, dermatological complications of diabetic neuropathy, and nephropathy. Finally, associated hereditary syndromes may cause collagenomas, fibromas/angiofibromas, lipomas in multiple endocrine neoplasia type 1 (MEN1) syndrome; café-au-lait macules, early onset neurofibromas, juvenile xanthogranuloma (involving non-Langerhans cell histiocytes), and intertriginous freckling in neurofibromatosis type 1. Clinical findings are differentiated from pseudo-acromegaly such as pachydermoperiostosis. Iatrogenic rash, lipodystrophy (lipoatrophy with/without lipohypertrophy) are rarely reported after pegvisomant/somatostatin analogues or after insulin use for DM. Experiments using human cell lines have shown that GH/IGF-1 over-secretion are prone to epithelial-to-mesenchymal transition (EMT) in melanoma. In non-acromegalic subjects, the exact role of GH/IGF-1 in skin tumorigenesis is yet to be determined. Skin in acromegaly speaks for itself, either as the first step of disease identification or as a complication or part of a complex syndromic context.