Main complaints and diagnostic algorithm
Taking a history in skin and integument pathologies relies on three key complaints: the appearance of various rashes, changes in the usual color, and skin itching (pruritus). The latter symptom is a crucial subjective sign that requires the clinician to perform a competent differential diagnosis between local dermatological processes and systemic diseases.
Algorithm of diagnostic search for pruritus:
- Exclusion of local causes. First of all, it is necessary to ensure the absence of trivial dryness (xerosis), which is the most common trigger.
- Search for objective markers. The physician examines the body for excoriations (scratch marks). Their detection reliably confirms the intensity and duration of discomfort reported by the patient.
- Assessment of allergic and toxic genesis. Food allergies, intolerance to medications (drugs), and the presence of urticaria (urticaria) are excluded.
Pruritus as a symptom of internal pathologies
If local and allergic causes are ruled out, pruritus is considered a marker of somatic diseases. It may indicate damage to a number of systems:
- Hepatobiliary system: In cholestasis syndrome, bile retention occurs. Hyperbilirubinemia develops and bile acids accumulate, irritating receptors. This is typical of biliary obstruction, primary biliary cholangitis, and drug-induced liver injury. Intrahepatic cholestasis of pregnancy is distinguished separately.
- Kidneys: Patients with end-stage chronic kidney disease (CKD) suffer from "uremic pruritus" resulting from severe intoxication of the body.
- Endocrine system: Diabetes mellitus is frequently accompanied by generalized or localized itching sensations.
- Oncology and hematology: The symptom serves as an alarming signal in lymphoproliferative disorders (lymphomas, Hodgkin's lymphoma), abdominal organ tumors, and blood disorders (e.g., polycythemia vera — erythremia).
Additionally, the physician always excludes parasitic infestations: pediculosis, helminthiases, and scabies (scabies). The psychogenic factor arising against the background of severe stress cannot be discounted either. The clinical significance of the symptom is colossal: intense suffering leads to persistent insomnia and severe psycho-emotional disorders, up to suicidal ideation.
Physical examination technique
The transition from questioning to physical examination requires adherence to strict rules ensuring the reliability of the data obtained.
Rules for conducting the examination:
- Synchronicity: Inspection and palpation are always performed simultaneously, organically complementing each other.
- Conditions: The patient must be completely undressed so that the physician can assess the entire body surface, not just open areas.
- Lighting: The fullest possible illumination is required. Daylight is the optimal option, as it allows for the correct perception of the finest color shades.
Key evaluation parameters:
- Color and presence of rashes. The physician records spots, papules, vesicles, and other elements. Initial differentiation of the rash is performed (e.g., checking whether the element disappears upon pressure).
- Moisture. The severity of sweating or the presence of pathological dryness is assessed.
- Turgor. The firmness and elasticity of tissues are determined via palpation.
- Temperature. Both local temperature (over a specific area or inflammation) and general skin temperature are assessed.
Briefly: answers to topical questions
What primary and secondary morphological elements of skin rashes are distinguished in propedeutics?
The following primary morphological elements of rashes are distinguished in propedeutics.
- Macule (macula) — a change in skin color without alteration of relief.
- Roseola (roseola) — an inflammatory spot up to 1 cm.
- Erythema (erythema) — a localized hyperemia larger than 1 cm.
- Petechia (petechia) — a pinpoint capillary hemorrhage.
- Purpura (purpura) — multiple small hemorrhages.
- Ecchymosis (ecchymosis) — a large hemorrhage.
- Papule (papula) — a solid formation up to 1 cm.
- Vesicle (vesicula) — a cavity up to 5 mm with serous contents.
- Bulla (bulla) — a cavity larger than 5 mm with exudate.
- Pustule (pustula) — a vesicle filled with pus.
- Wheal (urtica) — the primary element of an allergic rash.
The classification of secondary elements is not provided in the sources.
How is inflammatory hyperemia differentiated from hemorrhagic rashes during examination?
Diascopy is used to differentiate inflammatory hyperemia from hemorrhagic rashes. This method consists of pressing a glass slide against the rash element or stretching the skin around it. Under such impact, vascular spots (hyperemia) pale or completely disappear. Hemorrhagic spots resulting from vascular wall damage and blood extravasation do not change their color and do not pale upon pressure.
What pathological changes in the color of mucous membranes and sclera can be detected during examination?
The following changes in the color of mucous membranes and sclera may be detected during physical examination:
- Yellowish discoloration of the sclera and mucous membranes (the primary localization of staining in hyperbilirubinemia is the frenulum of the tongue).
- Bright red coloration of the tongue (Hunter's or "raspberry" tongue).
- Pale gray or brown coating on the mucous membrane of the tongue.
- Change in the color of the tongue papillae to black or brown (in "hairy tongue").
- Telangiectasias (spider veins) on the mucous membrane.
What specific skin color changes are characteristic of chronic primary adrenocortical insufficiency (Addison's disease)?
Addison's disease is characterized by the development of acquired generalized melanosis, manifesting as hyperpigmentation of the skin and mucous membranes. The color change is associated with increased melanin synthesis in the skin and mucous membranes. Pathogenetically, this is due to adrenal destruction, decreased blood cortisol levels, increased ACTH secretion via a negative feedback loop, the melanin-stimulating effect of ACTH, tyrosinase activation, and enhanced melanin synthesis. Sources also indicate a mechanism via increased production of corticotropin and other POMC derivatives, specifically melanocyte-stimulating hormone.
For differential diagnosis of systemic pruritus, remember the target organs: LIVER (cholestasis, bile acids), KIDNEYS (uremia in CKD), BLOOD (lymphomas, erythremia), and ENDOCRINE SYSTEM (diabetes mellitus).
Class and exam questions
Artificial lighting (especially incandescent lamps) can distort yellow and red shades. Because of this, the physician risks missing mild hyperbilirubinemia or misjudging the nature of hyperemia.
Artificial lighting (especially incandescent lamps) can distort yellow and red shades. Because of this, the physician risks missing mild hyperbilirubinemia or misjudging the nature of hyperemia.
How to objectively prove that a patient is experiencing severe itching?
The main objective confirmation of the intensity and duration of discomfort is the presence of excoriations on the body — characteristic scratch marks.
What cause should be ruled out first when patients present with excoriations?
First of all, it is necessary to exclude trivial dryness (xerosis), as it is the most common local cause.
What is the underlying mechanism of pruritus in hepatobiliary disorders?
The symptom occurs within the framework of cholestasis syndrome due to bile stasis, hyperbilirubinemia, and the accumulation in the blood of bile acids that irritate nerve endings.
What else to study on this topic
- Method for assessing tissue turgor and elasticity
- Differentiation of rashes: elements that disappear and do not disappear upon pressure
- Pathogenesis of uremic pruritus in chronic kidney disease
- Characteristics of rashes and pigmentation in endocrine disorders
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