Definition

1. Noun:

   • Skin scale: A small, thin, plate-like piece of dead skin that naturally detaches from the epidermis, often associated with dry skin conditions or certain dermatological diseases.
   • Dandruff: When referring to the scalp, "vảy da" commonly means dandruff—white or greyish flakes of dead skin cells that shed from the scalp.

2. Noun (medical/biological context):

   • Squama (plural: squamae): The technical term for a scale or scaly layer of skin, used in medical and zoological descriptions.

Usage Examples

• Noun:
  • Da đầu anh ấy có nhiều vảy da. (His scalp has a lot of dandruff.)
  • Bệnh vẩy nến làm xuất hiện những mảng vảy da bạc trắng. (Psoriasis causes patches of silvery-white skin scales to appear.)
  • Con rắn lột xác để loại bỏ lớp vảy da cũ. (The snake sheds its skin to remove the old layer of scales.)

Advanced Usage

• In dermatology, "vảy da" is a symptom, not a diagnosis. It is observed in conditions like eczema, seborrheic dermatitis, and ichthyosis.
• The spelling "vẩy da" (with a hook on the vowel) is also commonly used and considered a variant.

Variants and Related Words

• Vảy (n): A general term for a scale (on fish, reptiles, or skin).
• Vảy nến (n): Psoriasis scale; the specific thick, silvery scale characteristic of psoriasis.
• Tróc vảy da (v): To desquamate; to peel or shed skin scales.

Synonyms

• Flake: A small, thin piece of skin, especially one that has peeled off.
• Scale: A more general term for a small, hard plate forming part of an animal's skin or a skin condition.
• Dandruff: Specifically for scales of dead skin on the scalp.

Related Terms and Notes

• Desquamation (n): The medical term for the process of shedding or peeling off in scales.
• "Vảy da" is often confused with "vảy" alone, which can mean fish scales or reptile scales. The context usually clarifies the meaning.