Alterations in the physical properties of the skin
Assessment of the condition of the skin is based on the analysis of its moisture, temperature, elasticity, and keratinization features.
Moisture changes
- Hyperhidrosis (increased moisture) can be generalized (associated with fever, thyrotoxicosis, pain, or hypoglycemia) and localized (a marker of autonomic dysfunction, common in adolescents).
- Skin dryness is pathogenetically divided into two conditions: hypohidrosis (decreased sweat production associated with systemic dehydration) and xerosis (sebum deficiency, characteristic of ichthyosis, hypothyroidism, and vitamins A and PP deficiencies).
Temperature reactions
- Elevation: generalized occurs in fever, while localized indicates an acute inflammatory process in the underlying tissues.
- Decrease: systemic hypothermia reflects hemodynamic disorders (shock, circulatory failure) or hypothyroidism. Localized temperature decrease indicates vascular spasm (e.g., in Raynaud's syndrome).
Turgor and elasticity disorders Decreased elasticity is a striking marker of dehydration (in profuse vomiting or diarrhea), as well as prolonged infections, profound dystrophies, and hypothyroidism. Localized induration with loss of extensibility is typical for scleroderma.
Types of desquamation and keratinization
- Lamellar: coarse scaling, characteristic of bedridden patients on the soles.
- Fine-scaled: accompanies endocrine disorders and infections (measles).
- Iatrogenic: contact reaction to local procedures (mustard plasters, iodine).
- Keratinization disorder (extreme degree): formation of dense horny plates, which is a pathognomonic sign of ichthyosis.
Toxicoderma: drug-induced rash
Drug reactions are most frequently provoked by antibiotics (beta-lactams, sulfonamides), anticonvulsants, and antiretroviral drugs. The typical course presents as a morbilliform pruritic rash occurring in the first two weeks of drug intake.
Severe life-threatening forms:
- Urticaria and anaphylaxis: rapid development of pruritic erythematous elements, laryngeal edema and shock are possible.
- DRESS syndrome: delayed reaction (in 2–6 weeks). Combines rash with internal organ involvement (hepatitis), fever, arthralgia, and eosinophilia.
- Stevens-Johnson syndrome: generalized macular rash with fever, mucous membrane involvement (erosive stomatitis), and ocular involvement.
- Toxic epidermal necrolysis (Lyell's syndrome): total mucosal involvement and massive epidermal detachment.
Systemic and genetic syndromes
Skin manifestations often serve as a key to diagnosing complex hereditary and systemic diseases.
- Sézary syndrome: malignant pathology accompanied by exfoliative erythroderma, generalized pruritus, and plantar hyperkeratosis. Burning sensation and telangiectasias occur in the oral cavity.
- Sturge-Weber-Krabbe syndrome: neuroectodermal dysplasia. Characterized by the presence of a port-wine stain (Nevus flammeus) in the trigeminal nerve innervation zone, glaucoma, and epilepsy.
- Werner syndrome (adult progeria): premature aging. Manifests as skin thinning, subcutaneous fat atrophy, early alopecia, and juvenile cataract.
- Bloom syndrome: dwarfism combined with telangiectatic erythema on the face (aggravated by sunlight) and bullous eruptions.
- Spiru's syndrome (fluorosis): occurs due to excess fluoride in water. Leads to dental enamel and nail dysplasia, hair dystrophy, and is accompanied by neurological disorders.
For memorizing severe drug reactions by time: Anaphylaxis — minutes; Morbilliform rash — up to 14 days; DRESS syndrome — from 2 to 6 weeks.
Class and exam questions
What is the difference between hypohidrosis and xerosis?
Hypohidrosis is a consequence of dehydration with decreased sweat production. Xerosis is associated with decreased sebum production (in hypovitaminoses, ichthyosis).
What to do at the first signs of toxicoderma?
The primary and most important rule in the development of a severe drug rash is to immediately withdraw the drug that provoked the reaction.
How does seborrheic dermatitis manifest against the background of HIV?
It can be polyetiological. Characterized by erythematous plaques with greasy crusts on the scalp, face, and chest. Treated with topical glucocorticosteroids and antifungal agents.
What else to study on this topic
- Dental and maxillofacial manifestations in systemic syndromes (Brooke-Spiegler, van der Woude, Steinton-Capdepont)
- Pathogenesis and treatment regimens for seborrheic dermatitis in immunodeficiencies
- Hemorrhagic skin manifestations (using Werlhof's disease as an example)
- Necrotic tissue changes in Wegener's granulomatosis
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