Vascular pattern of the palms--a clinical feature of atopic skin diathesis

Sub-clinical assessment of atopic dermatitis severity using angiographic optical coherence tomography

Measurement of sub-clinical atopic dermatitis (AD) is important for determining how long therapies should be continued after clinical clearance of visible AD lesions. An important biomarker of sub-clinical AD is epidermal hypertrophy, the structural measures of which often make optical coherence tomography (OCT) challenging due to the lack of a clearly delineated dermal-epidermal junction in AD patients. Alternatively, angiographic OCT measurements of vascular depth and morphology may represent a robust biomarker for quantifying the severity of clinical and sub-clinical AD. To investigate this, angiographic data sets were acquired from 32 patients with a range of AD severities. Deeper vascular layers within skin were found to correlate with increasing clinical severity. Furthermore, for AD patients exhibiting no clinical symptoms, the superficial plexus depth was found to be significantly deeper than healthy patients at both the elbow (p = 0.04) and knee (p<0.001), suggesting that sub-clinical changes in severity can be detected. Furthermore, the morphology of vessels appeared altered in patients with severe AD, with significantly different vessel diameter, length, density and fractal dimension. These metrics provide valuable insight into the sub-clinical severity of the condition, allowing the effects of treatments to be monitored past the point of clinical remission.

Palmar erythema

Palmar erythema (PE), an often overlooked physical finding, is due to several physiologic or systemic pathologic states. PE can exist as a primary physiologic finding or as a secondary marker of systemic pathology. Primary or physiologic PE can be due to heredity, occurs in at least 30% of pregnant women as a result of associated alterations in the function of the skin and its microvasculature, or may be a diagnosis of exclusion (i.e. idiopathic PE). Secondary PE from systemic pathology encompasses a wide range of disease states. Twenty-three percent of patients with liver cirrhosis, from varying causes, can manifest PE as a result of abnormal serum estradiol levels. Patients with a rare neonatal liver disease such as Wilson disease and hereditary hemochromatosis may exhibit PE along with the other systemic manifestations of the genodermatoses. PE has been reported to occur in >60% of patients with rheumatoid arthritis and is associated with a favorable prognosis. Up to 18% of patients with thyrotoxicosis and 4.1% of patients with diabetes mellitus can have PE. This cutaneous manifestation of diabetes occurs more often than the more classic diseases such as necrobiosis lipoidica diabeticorum (0.6%). PE can be seen in early gestational syphilis and among patients with human T-lymphotrophic virus-1-associated myelopathy. Drug-induced PE with hepatic damage has been documented with use of amiodarone, gemfibrozil, and cholestyramine, while topiramate and albuterol (salbutamol) have been reported to cause PE in the setting of normal liver function. Fifteen percent of patients with both metastatic and primary brain neoplasms may have PE. Increased levels of angiogenic factors and estrogens from solid tumors have been postulated as the cause of PE in such cases. Erythema ab igne can mimic PE, and patients with atopic diathesis are more likely to have PE than matched control subjects. Smoking and chronic mercury poisoning are environmental causes of PE.No treatment of primary PE is indicated. If medication is the cause of PE, the drug responsible should be discontinued if possible. Identification of PE related to underlying disorders should be followed by treatment of the underlying condition. In light of the numerous etiologies of PE, this article reviews the current literature and provides a framework to help guide the clinician in determining the cause of PE in patients presenting with this finding.