Vascular and pigmented disorders
Changes in skin color and microcirculation are key diagnostic criteria for many rheumatological and somatic diseases.
- Raynaud's syndrome: Characterized by a sharp change in hand coloration. During the vasospasm phase (ischemic stage), arterial inflow is disrupted, causing distinct skin pallor with a clear border of ischemic zones. The process is bilateral, often affecting the ring fingers and fifth digits.
- Telangiectasias (spider veins): Located haphazardly, often on the anterior chest wall. The lesion has a central feeding arteriole from which tortuous capillaries branch out ("spider legs"). The bright red color indicates the arterial origin of the blood. The vessels thin out at the periphery with no clear borders against the skin.
- Jaundice (Icterus): Diffuse yellow discoloration of the skin (e.g., on the abdomen). Indicates hyperbilirubinemia due to hemolysis or hepatobiliary pathology.
- Vitiligo: Autoimmune destruction of melanocytes leading to achromia (depigmentation). Manifests as milky-white patches (maculae) with scalloped edges. The lesions are symmetrical, affect exposed areas of the body (chest, shoulders), and tend to coalesce. Inflammatory signs are completely absent.
Markers of metabolic disorders
Disorders of lipid metabolism may present with specific external manifestations on the face and eyes.
- Xanthelasma palpebrarum (Xanthelasma palpebrarum): Appears as a flat plaque or papule of straw-yellow or orange color. The lesions are soft, with clear borders, located symmetrically at the medial angles of the eyes (most often on the upper eyelids). This is a cutaneous marker of dyslipidemia requiring screening for atherosclerosis.
- Arcus senilis of the cornea (arcus senilis, gerontoxon): A whitish or grayish annular opacity at the periphery of the cornea, encircling the iris. Formed due to the deposition of cholesterol and phospholipids. While considered a normal variant in the elderly, it indicates hypercholesterolemia in young patients.
Endocrine skin manifestations
Hormonal imbalances cause characteristic changes in the structure of the skin and its appendages.
- Hirsutism: Excessive growth of terminal hair in women in androgen-dependent areas (chin, cheeks, sideburns, neck). Unlike vellus hair, terminal hair is long, coarse, and pigmented. Hirsutism is often accompanied by acne (erythematous and papulopustular lesions) in the lower third of the face, which is a sign of hyperandrogenism and virilization.
- Specific striae (striae rubrae / purpurea): Wide stretch marks on the abdomen with a crimson or purple-bluish color. This is a classic sign of Cushing's syndrome (hypercortisolism). Due to the catabolic effect of excess cortisol on collagen, the skin thins, and blood vessels show through. Unlike striae seen in obesity or pregnancy, Cushingoid striae do not fade.
Briefly: answers to topical questions
What phases of skin color change are distinguished in the classic course of Raynaud's syndrome?
The classic course of Raynaud's syndrome features a specific triad of skin color changes occurring in three successive phases. The pathological process includes the following stages of paroxysmal spasm:
- Pallor — the stage of distal ischemia accompanied by a sensation of chilliness;
- Cyanosis — the stage of cyanosis occurring against the background of pronounced tissue hypoxia;
- Rubor / Redness — the stage of reactive hyperemia, where cyanosis is replaced by redness, accompanied by paresthesias and pain.
What other skin manifestations, besides striae, are characteristic of Cushing's syndrome?
In addition to striae, sources indicate the following cutaneous or visually determined manifestations in Cushing's syndrome / hypercortisolism:
- Purple facial flush — plethoric facies / "matronism";
- Acne vulgaris — acne;
- Skin thinning;
- Vascular fragility, leading to hemorrhages;
- Delayed healing of wounds and cuts.
What diseases, besides hemolysis and hepatobiliary pathology, can cause yellow skin discoloration?
In the cited sources, true jaundice associated with bilirubin accumulation is attributed to hepatobiliary pathology and hemolysis. Other diseases as a cause of true jaundice are not listed in the materials.
Causes of yellow skin discoloration not caused by bilirubin—i.e., pseudojaundice—are described separately:
- Hypercarotenemia — excessive consumption of carotene-rich foods, such as carrots or tomatoes;
- Medication-induced pigmentation — intake of mepacrine (acrichine) or picric acid salts.
Key distinguishing feature of pseudojaundice: the sclerae remain white, only the skin is discolored.
Class and exam questions
How do vellus hairs clinically differ from terminal hairs in hirsutism?
Terminal hairs are coarse, long, thick, and dark. Vellus hairs are soft, short, and unpigmented.
What does the appearance of spider veins on the chest indicate?
These are telangiectasias consisting of a central arteriole and capillaries. The bright red color indicates arterial blood within the lesion.
What else to study on this topic
- Pathophysiological mechanisms of vasospasm in Raynaud's syndrome.
- Differential diagnosis of types of jaundice based on clinical presentation.
- Autoimmune genesis of vitiligo and mechanisms of melanocyte destruction.
- Catabolic effect of cortisol on collagen synthesis in the dermis.
- Association between hyperandrogenism and the development of papulopustular acne.
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