This type of ‘poor circulation’, often familial, is more common in females than males. The hands, feet, nose, ears and cheeks become blue–red and cold. The palms are often cold and clammy. The condition is caused by arteriolar constriction and dilatation of the subpapillary venous plexus, and to cold-induced increases in blood viscosity. Patients have normal peripheral pulses, in contrast to those with peripheral arterial occlusive disease. The best answers are warm clothes and avoidance of cold.

This occurs in fat, often young, women. Purple–red mottled discoloration is seen over the fatty areas such as the buttocks, thighs and lower legs. Cold provokes it and causes an unpleasant burning sensation. Most young people outgrow the condition, but an area of acrocyanosis or erythrocyanosis may be the site where other disorders will settle in the future (e.g. perniosis, erythema induratum, lupus erythematosus, sarcoidosis, cutaneous tuberculosis and leprosy). Weight reduction is often recommended.

This is a rare paroxysmal condition in which the extremities (most commonly the feet) become red, hot, swollen and painful when exposed to heat, and relieved by cooling. The condition may be sporadic or familial. Secondary erythromelalgia is associated with a myeloproliferative disease (e.g. polycythaemia rubra vera or thrombocythaemia), lupus erythematosus, rheumatoid arthritis, diabetes, degenerative peripheral vascular disease or hypertension. Elevation and cooling of the extremities can be helpful. Small doses of aspirin give symptomatic relief. Topical therapies include capsaicin cream and lidocaine patch. Alternatives include non-steroidal anti-inflammatory drugs (NSAIDs), gabapentin, beta-blockers, pentoxifylline and the serotonin re-uptake inhibitor venlafaxine.

Erythema accompanies all inflammatory skin conditions, but the term ‘the erythemas’ is usually applied to a group of conditions with redness but without primary scaling. Such areas are seen in some bacterial and viral infections such as toxic shock syndrome and measles. Drugs are another common cause (see Chapter 25). If no cause is obvious, the rash is often called a ‘toxic’ or ‘reactive’ erythema.

When erythema is associated with oedema (urticated erythema) it becomes palpable.

These stellate telangiectases do look rather like spiders, with legs radiating from a central, often palpable, feeding vessel. If the diagnosis is in doubt, press on the central feeding vessel with the corner of a glass slide and the entire lesion will disappear. Spider naevi are seen frequently on the faces of normal children, and may erupt in pregnancy or be the presenting sign of liver disease, with many lesions on the upper trunk. Liver function should be checked in those with many spider naevi. The central vessel can be destroyed by electrodessication without local anaesthesia or with a vascular laser (p. 380).

This cyanosis of the skin is net-like (reticulated) or marbled and caused by stasis in the capillaries furthest from their arterial supply: at the periphery of the inverted cone supplied by a dermal arteriole (see Figure 2.1). It may be widespread or localized. Cutis marmorata is the name given to the mottling of the skin seen in many normal children. It is a physiologic vasospastic response to cold exposure and disappears on warming, whereas true livedo reticularis remains.

Some patients with an apparently idiopathic livedo reticularis develop progressive disease in their peripheral, cerebral, coronary and renal arteries. Others, usually women, have multiple arterial or venous thrombo-embolic episodes accompanying livedo reticularis. Recurrent spontaneous abortions and intrauterine fetal growth retardation are also features. Prolongation of the activated partial thromboplastin time (APTT) and the presence of antiphospholipid antibodies (either anticardiolipin antibody or lupus anticoagulant, or both) help to identify this syndrome. Systemic lupus erythematosus should be excluded (p. 126).

This is a common paroxysmal vasospasm of the digital arteries provoked by cold or, rarely, emotional stress. The result is a characteristic progression of white, blue and red discoloration of the fingers. At first, the top of one or more fingers becomes white due to vasoconstriction. A painful cyanosis then appears as the residual blood in the finger desaturates. On rewarming, the rapid reperfusion of the digit turns the area red before the hands return to their normal colour.

This is discussed in Chapter 8, p. 110.

This condition, also termed giant cell arteritis, is a vasculitis of the large and middle-sized blood vessels of the head and neck. It affects elderly people and may be associated with polymyalgia rheumatica. The classic site is the temporal arteries, which become tender and pulseless, in association with severe headaches, jaw claudication and constitutional symptoms (malaise, fever, weight loss). Rarely, necrotic ulcers appear on the scalp. Blindness may follow if the ophthalmic arteries are involved and, to reduce this risk, systemic steroids should be given as soon as the diagnosis has been made. A temporal artery biopsy is the gold standard test for diagnosis. In active phases the erythrocyte sedimentation rate (ESR) is high and its level can be used to guide treatment, which is often prolonged.

This occlusive disease, most common in developed countries, is not discussed in detail here, but involvement of the large arteries of the legs is of concern to dermatologists. It may cause intermittent claudication, nocturnal cramps, ulcers or gangrene. These may develop slowly over the years or within minutes if a thrombus forms on an atheromatous plaque. The feet are cold and pale, the skin is often atrophic, with little hair, and peripheral pulses are diminished or absent.

Investigations should include urine testing to exclude diabetes mellitus. Fasting plasma lipids (cholesterol, triglycerides and lipoproteins) should be checked in the young, especially if there is a family history of vascular disease. Doppler ultrasound measurements help to distinguish atherosclerotic from venous leg ulcers in the elderly (see Venous hypertension: investigations). Complete assessment is best carried out by a specialist in peripheral vascular disease or a vascular surgeon.