Basic Skin Lesions in Dermatology

I. Primary Basic Lesions

1. Skin Color Changes

• Patch:

• Flat on the skin, no infiltration.

• Red Patch:

• Pink or red, fades when pressed.

• Flat with the skin.

• Cause: Vasodilation due to inflammation.

• Clinical forms: Measles-like, roseola (secondary syphilis), erythema, generalized erythema.

• Vascular Patch:

• Vasodilation in the dermis.

• Detection: Disappears when pressed, reappears gradually when releasing.

• Hemorrhagic Patch:

• Red blood cells escape from blood vessels.

• Color changes: Pink – dark red – blue – yellow – disappears.

• Size: ≥ 2mm/ dot.

• Detection: Does not fade when pressed.

• Pigmented Patch:

• Skin lesion with darker color.

• Depigmented Patch:

• Found in diseases: Vitiligo/ albinism.

2. Fluid Lesions

• Vesicle:

• Blister of the epidermis, containing fluid.

• Size: < 5mm.

• Determination: Blunt needle puncture reveals fluid.

• Bulla:

• Blister of the epidermis, containing fluid.

• Size: > 5mm.

• Shape: Round/ hemispherical.

• Contains: Serum +- pus, blood.

• Position relative to epidermis: Above/ below.

• Pustule:

• Location: Under the stratum corneum/ under the epidermis.

3. Solid Lesions

• Papule:

• Firm lesion, protruding above the skin, < 1cm, no fluid.

• Base attachment: Epidermis/ superficial dermis/ hair follicle.

• Nodule/ Tubercle:

• Firm lesion, round, raised, < 1cm (deeper than papule), palpable.

• Location: Dermis/ subcutaneous tissue.

• Plaque:

• Cause: Cellular infiltration in the superficial/ deep dermis.

• Verruca:

• Tumor of the epidermal papillary tissue, uneven surface.

• Cause: Proliferating papillary layer of the epidermis, infiltration of mononuclear white blood cells in the dermis.

• Gumma:

• Size: Apple-sized/ larger.

• Cause: Cellular infiltration in the dermis, subcutaneous tissue.

• Stages of progression: Hard – soft – purulent rupture, ulceration – scarring.

II. Secondary Basic Lesions

• Scale:

• Thin layer of stratum corneum separating from the epidermis/ cornification disorder.

• Crust:

• Dried secretions forming a crust.

• Types: Serum, pus, blood, blood + pus.

• Color: Serum (ivory), pus (yellow), blood (dark/ brown), blood + pus (black + yellow).

• Scratch:

• Does not leave scars.

• Erosion:

• Does not leave scars.

• Ulcer:

• Loss of skin to the dermis/ subcutaneous tissue.

• Leaves scars.

• Skin Atrophy:

• Epidermis/ superficial dermis becomes thinner due to degeneration of connective tissue/ elastic fibers.

• Sclerosis:

• Collagen in the dermis thickens.

• Lichenification:

• Thickened area of skin, darker color, infiltrated.

• Prominent skin lines.

• Chronic itching.

III. Differentiation and Recognition

• Papule: Located in the epidermis and superficial dermis, may or may not be located in the hair follicle.

• Bulla: Epidermis (superficial bulla)/ below the epidermis (deep bulla).

• Generalized erythema: >= 90% of the body surface.

• Differentiating congestive and hemorrhagic patches: Congestive patches disappear when pressed, hemorrhagic patches do not fade.

IV. Some Diseases and Lesions

• Pemphigus: Superficial blisters, wrinkled, easily rupture on intact skin.

• Nikolsky: Sign indicating epidermal damage (pemphigus, Lyell).

• Tzank cells: Scraping the base of blisters -> glass slide.

• (+) alone: Pemphigus.

• (+) and multinucleated giant cells: Virus: Shingles, Herpes.

• Nodule: Erythema nodosum.

• Gumma:

• Tuberculosis: Dirty, ragged edges.

• Tertiary syphilis: Smooth, well-defined edges.

• Deep fungal infection: Along lymphatic pathways.

• Scale: Indicates epidermal damage.

• Honeycomb crust: Impetigo.

• Scar: Dermis, subcutaneous tissue damage -> fibrotic proliferation.

V. Medications and Therapies

• Ointment: Powder content > 20%, deeply penetrates the skin, used for chronic stages, thickened skin, has anti-inflammatory, desquamating effects.

• Lotion: Powder content tacl, glycerin, zinc oxide. Does not contain boric acid.

VI. Some Notes

• Sexually transmitted diseases: Common in the age group 15-49.

• Skin diseases: Caused by bacteria, viruses and parasites.

• Disease burden in age > 60: Dermatitis, urticaria, psoriasis, skin cancer.

• Disease burden in age 20-30: Acne.

• Common skin disease in age 25-29: Acne.

• Xamogel: Contains betamethasol + calcipotriol.

• Powder content ratio in lotion: 20-50%.

VII. Some Frequently Asked Questions

• Emergency blistering disease in dermatology: Epidermolysis bullosa.

• Castellani’s solution: Do not apply to mucous membranes of eyes and nose, do not apply over large areas.

• Plaque psoriasis: Size 5-10cm, clearly demarcated from normal skin.

VIII. General Note

This article only provides general information about basic skin lesions in dermatology. For effective diagnosis and treatment of skin diseases, you should consult a dermatologist.