Is a bluish discoloration of the skin due to lack of oxygen in the blood quizlet?

Indian J Dermatol. 2013 Nov-Dec; 58(6): 417–420.

Abstract

Introduction:

It is a functional peripheral vascular disorder characterized by bluish discoloration of skin and mucous membrane due to diminished oxyhemoglobin. It may be due to central or local tissue oxygenation defects. It is a painful episodic disorder, where trophic changes and ulceration are very rare except in necrotizing variant. By definition, it refers to persistent abnormally deep blue or cyanotic discoloration of skin over extremities (hand and feet most commonly) due to decreased oxyhemoglobin.

Etiology:

It can be both primary and secondary to psychiatric, neurologic, autoimmune, infective, metabolic and other causes. The existing hypothesis suggests the prevailing role of vasospastic reaction over possible blood rheology impairment.[1] As per the current line of thinking, it is due to chronic vasospasm of small cutaneous arteries, and arterioles along with compensatory dilatation in the capillary and post capillary venules causes cyanosis and sweating.

Clinical Features:

Acrocyanosis is an uncommon condition. It usually presents with coolness and violaceous dusky discolorations of hands and less frequently the feet. Other peripheral part like ear, nose, lips and nipple can also be affected.[2] The changes may be transient after cold exposure but frequently persist during winter and even in summer.

Management:

There is no standard and curative medical or surgical treatment of acrocyanosis. In mild cases, it is unnecessary to give any drug treatment. Life style modification, dietary and hygiene counseling, avoidance of cold and reassurance that the bluish skin discoloration does not indicate any serious illness is all that is necessary.

Keywords: Acrocyanosis, life style modification, pain, raynauds, vasospasm

Introduction

What was known?

Acrocyanosis is a painless dusky discoloration of peripheral extremity caused by vasospasm persisting throughout the year. Decreased oxyhemoglobin and alternation of blood rheology is important.

Acrocyanosis is a functional peripheral vascular disorder and is much less common than other acrosyndromes (Raynauds phenomenon and erythromelalgia). The term acrocyanosis is derived from the words akron (extremity) and kyanos (blue). Cyanosis is bluish discoloration of skin and mucous membrane due to reduced oxyhemoglobin within the vessel at dermis and hypodermis. Generally, there are two possible reasons for peripheral acrocyanosis: Some pulmonary and cardiac conditions, causing central oxygenation problems, and second is due to local tissue oxygenation defect. Literally, acrocyanosis means bluish discoloration of the extremities due to decreased amount of oxygen delivered to the peripheral part. It is a persistent disorder without episodic triphasic color response. Acrocyanosis is usually painless. Trophic changes and ulceration are extremely rare except in remittent necrotizing variety. It mainly affects the hands; sometimes, feet and face. By definition, it refers to persistent abnormally deep blue or cyanotic discoloration of skin over extremities (hand and feet most commonly) due to decreased oxyhemoglobin. Crocq (1896) first used the word “acrocyanosis” to describe the condition.

Epidemiology

Incidence of acrocyanosis is not definitely known as there is no such report. It is more prevalent in children and young adults usually in persons younger than 30 years old.[3] Risk factors of acrocyanosis are cold climate, outdoor occupation, low body mass index (BMI).[4] Primary acrocyanosis is more commonly seen in women, this may be due to low BMI in females than males. Higher cosmetic concern in women may be another reason for increased reporting in females. Acrocyanosis is not infrequent in persons with major neurological deficit, especially with paresis or paralytic patients. It is also observed more commonly in emotionally and mentally disturbed person with anorexia nervosa (BMI is significantly low). Acrocyanosis has also been reported after delivery in both preterm and full term newborns.[5]

Etiology

Although all evidence points to cold as the essential precipitating factor, underlying causative disorder may be varied. Acrocyanosis can be categorized as primary (also called Idiopathic or Essential acrocyanosis) when no known underlying disorder could be found even after proper investigation and called secondary when it occurs in association with a specific disease or after drug administration. Common causes of acrocyanosis are the following:

Remittent idiopathic necrotizing acrocyanosis is a very rare condition characterized by persistent systemic cyanotic or erythrocyanotic discoloration of hands and feet. It is associated with pain, tenderness of fingers and toes and may present as ulceration or gangrene of extremities. It is aggravated with cold exposure but persists even in summer.

Clinical Features

Acrocyanosis is an uncommon condition. It is usually presented with coolness and violaceous dusky discolorations of hands and less frequently the feet. Other peripheral parts like ear, nose, lips and nipple can also be affected.[2] The changes may be transient after cold exposure but frequently persist during winter and even in summer.[6] The extremities often are cold and clammy and less frequently associated with swelling.[7] The palms and Soles exhibit a wide range of sweating from moderately moist to profuse hyperhidrosis. The moisture is more on volar and planter surface than dorsum which is comparatively dry and cold. There is no associated pain and patients are normally asymptomatic aside from discoloration. Infrequently local edema when present may merely make the skin feel tight: A condition seen typically in fingers or rarely causes visible swelling with mild shiny appearance. Trophic skin changes and ulceration are not seen except in remittent necrotizing acrocyanosis. It is also associated with enhanced susceptibility to cooling and pain, as well as ulceration and gangrene of the fingers.[8]

Sensory changes are not seen and all peripheral pulses are normal in rate, rhythm and quality. In severe cases, the nails become irregular and brittle. Erythrocyanosis, perniosis, livedo reticularis may also be found in same patient. Exposure to cold temperature worsens acrocyanosis, while it often improves on warming. This cyanotic hue may changes to erythema with elevation of the dependent part.[9] In hot weather (when it persist in summer) and when the person is warm and active, the hands and feet may only be distinguished from the normal person by clamminess and a brownish-yellow tinge on the back of the hands.

It should be differentiated from closely related other acrosyndromes (Raynaud's phenomenon, perniosis and erythromelalgia) and vaso-occlusive disease. Raynaud's phenomenon is characterized by paroxysmal episode of triphasic or biphasic color change (white, red and bluish discoloration) of finger and toes.

Chilblain or pernios is also developed after cold exposure in digits with erythematous and purplish discoloration. Other symptoms like itching, burning and pain are often present in contrast to acrocyanosis. Conspicuous edema of the digits and tenderness are also prominent features in perniosis. Blisters, pustules and ulcerations are frequently seen in severe cases. All these findings are absent in acrocyanosis.

Erythrocyanosis is a dusky cyanotic discoloration of skin that occurs over areas with thick layer of subcutaneous fat such as over thigh, lower leg, buttock, forearm etc., It is commonly associated with angiokeratomas, keratosis pilaris and telangiectasia.[8] In vaso-occlusive disease like different vasculitic disorder, Buerger's disease, atherosclerotic disease, rheumatic disease and other collagen group of diseases,[9] thromboembolic disease peripheral pulse are usually abnormally low volume or absent in contrary to acrocyanosis. Ulceration and gangrene is a prominent feature which is not seen in acrocyanosis. When acrocyanotic limb is elevated it becomes pale as in normal person which rules out any venous occlusion. The classification is given in Table 1.

Table 1

Causes of acrocyanosis

Pathophysiology

To date, some aspects of acrocyanosis pathophysiology remain mostly unknown. The existing hypothesis suggests the prevailing role of vasospastic reaction over possible blood rheology impairment.[1] The current line of thinking is that it is due to chronic vasospasm of small cutaneous arteries and arterioles along with compensatory dilatation in the capillary and post capillary venules causes cyanosis and sweating.[7] Stasis in the papillary loops with aneurysmal dilatation at the tips, redistribute the blood flow to the subcapillary venous plexus. The blood flow may be compromised by altered erythrocyte flexibility, increased platelet adhesiveness and other plasma viscosity factors.[8] Though exactly not known, it has been postulated that this change in vascular tone can be due to an inherited defect in blood vessel musculature by disturbance in the nerves that control the dilatation and constriction of arteries (sympathetic nervous system), by injuries and by the drugs. Other hormones like norepinephrine (vasoconstrictor) may also contribute to acrocyanosis as seen in pediatric patient taking tricyclic antidepressant (TCA).[10] TCA can inhibit the reuptake of norepinephrine (α1 adrenergic activity) and thus increase its blood level. TCA also antagonize both H1 and H2 histaminergic receptors.[11] Local release of histamine from mast cell may be crucial in the maintenance of digital arterial blood flow as it acts as a vasodilator. So by blocking the action of histamine at blood vessel, imipramine may promote potent digital vasospasm in susceptible individual.[11]

In histological examination, small vessels are dilated and prominent in acrocyanosis mainly at papillary and subpapillary vessels but this finding is not consistent as in some subject nail fold capillaries appear within normal limit. Though Monticone et al. reported that capillary density was reduced compared with normal subject in their quantitative nail field capillary microscopy study, it was much higher than that of patients with systemic sclerosis.[12] Kobayasi et al. have found twisted collagen fibrils (TCF) in normal skin of an essential acrocyanosis patient and the presence of TCF is an ultrastructural sign for inherited malformation collagen fibrils. According to them, EA was probably elucidated as a vascular disorder in TCF carrying people and for pathogenesis, the inherited dysfunction in the hypertrophic pericytes of the subpapillary vascular plexus was presumed.[13]

Diagnosis

Acrocyanosis can be diagnosed clinically by proper history and physical examination. It is essential to differentiate it from Raynaud's phenomenon and chilblain. Capillary oxymetry will show a normal oxygen saturation ruling out vaso occlusive disease. Other laboratory investigations and imaging studies are only needed to know the etiology of secondary acrocyanosis depending on the clinical signs and symptoms of underlying disease in individual cases. Complete hemogram is essential for lymphoproliferative disease and essential thrombocythemia. Screening for antinuclear factor, rheumatoid factor, cardiolipin antibody and lupus antibody may be required for connective tissue disease and antiphospholipid antibody (APLA) syndrome. Metabolic screening like leucocytes oligosaccharide enzyme analysis of alpha-L-fucosidase deficiency may required for fucosidosis in suspected cases. CT scan, MRI, NCV etc., may require to rule out any underlying neoplastic disease, spinal cord injuries and nerving plexus neuropathy. But for practical purpose, capillaroscopy, which visualizes capillary venous stasis, is the only useful investigation in clinical practice for diagnosis of acrocyanosis, though not indispensable. So four clinical symptoms necessary and sufficient to establish the diagnosis are persistent and painless cyanosis of extremities, local hypothermia, sweatiness and elastic infiltration of the integument.[14]

Treatment

Treatments for Acrocyanosis:

• Reassurance

• Gloves/slippers

• Avoidance of exposure to cold

• Cease smoking

• Alpha blocker drugs and calcium channel blocker drugs.

There is no standard and curative medical or surgical treatment of acrocyanosis. In mild cases, it is unnecessary to give any drug treatment. Life style modification, dietary and hygiene counseling, avoidance of cold and reassurance that the bluish skin discoloration does not indicate any serious illness, is all that is necessary. Thick insulated clothing like insulated boots, thin polypropylene liner socks (to wick the moisture away from the skin and to maintain the normal skin temperature) is necessary for persons who have the illness and works at outdoor in cold climate. In severe cases, drugs like calcium channel blocker (CCB) and alpha adrenergic blocking agents (prazosin) can be used in the view of vasodilatory action of these drugs. But in clinical practice CCB like nifedipine and diltiazem are not very effective[2] but reasonable improvements have been seen in some patients. Topically applied nicotinic acid derivatives and minoxidil can be beneficial.[6] Sympathectomy or selectively disrupting only the fibers supplying the involved area will usually alleviate the cyanosis but such an extreme procedure would rarely be appropriate.[3] Specific treatment of underlying disease in secondary acrocyanosis is very much important because some of them are curable. Das et al.[15] showed good results with a combination of pentoxyfylline and diltiazem in remittent necrotizing variety.

Prognosis and Conclusion

This is usually a benign condition without any serious complication, except in remittent intermittent variety and secondary acrocyanosis with underlying serious disease. Although there is no cure, the prognosis is otherwise good without any increased risk of death and the patient can lead a normal life. According to the latest research, it is a vasospastic condition secondary to blood rheology alternation with mild improvement with drugs but main therapy is life style modification.

What is new?

Acrocyanosis is usually a benign condition and early diagnosis can prevent its morbidity.

Footnotes

Source of Support: Nil

Conflict of Interest: Nil.

References

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