A skin lesion is a part of the skin that has an abnormal growth or appearance compared to the skin around it. It can be either primary skin lesion or secondary skin lesions.
Common skin lesions.
(1) Macules: These are areas of skin discoloration which are neither raised nor depressed.A macule is a flat, distinct, discolored area of skin less than 1 centimeter (cm) wide. A large macule i.e Areas of discoloration that are larger than 1 cm are referred to as patches.
- congenital. (Albright’s syndrome, neurofibromatosis)
- Drug reaction.
- Infection. Viral (Measles, Rubella, non specific viral exanthem), Fungus (pityriasis versicolor), bacterial (Macular syphilide, tuberculoid leprosy, typhoid rose spots, common where typhoid is endemic).
- Immune mediated. ( Allergic reaction, vitiligo)
- Neoplastic. (lentigo maligna)
- Other. (Sun damage including freckles, pregnancy cholasma, Peutz-jeghers syndrome)
(2) Papules: These are circumscribed elevations of skin which are palpable with no visible fluid and diameter is less than 5 mm or upto 10 mm in diameter at the widest point.
- Congenital. (pseudoxanthoma elasticum, tuberous sclerosis)
- Other. (Acne, campbell de morgan spots, darier’s disease)
- Infection. (scabies)
- Systemic illness. (xanthomata, acanthosis nigricand)
- Malignancy.(kaposi sarcoma)
(3) Plaque: It is actually a broad papule, or confluences of papules which is greater than 1 cm.
Nodules:It is same as papules but the depth of nodules is more than 10 mm. Remember! it is the depth which differentiate nodules from papules.
- Malignancy. (lymphoma. metastatic carcinoma)
- Infections. (warts, leprosy, syphilis, lupus vulgaris, Fish tank and swimming pool granuloma, actinomycosis)
- Systemic disease. (xanthoma, sarcoidosis, vasculitis)
- Other. (Nodulocustic acne, keratoacanthoma, pyoderma gangrenosum)
(4) Vesicles: These are cystic swellings containing serous fluid and diameter is up to 5 mm.
(5) Bullae: These are cystic lesions of more than 5 mm containing serous , seropurulent or hemorrhagic fluid.
(6) Postules: These are small elevation of the skin similar to vesicles containing opaque, cloudy or purulent material usually consisting of necrotic inflammatory cells. These can be either white or red.
- Infection. bacterial (staphylococcal infection, impetigo, boils, folliculitis, sycosis barbea), Viral (Herpes simplex, herpes zoster, cowpox), fungus (candida).
- Other. (acne vulgaris, dermatitis herpetiformis, behcet’s syndrome)
- Drugs. reaction to medications.
(7) Wheals:These are swellings of skin due to acute localized edema. It usually disappear within 24 to 48 hours. The temporary raised bubble of taut skin on the site of a properly-delivered intradermal injection is also called a welt, with the ID injection process itself frequently referred to as simply “raising a wheal” in medical texts.
(8) Cyst: A cyst is an epithelial-lined cavity containing liquid, semi-solid, or solid material.
(9) Erosion: An erosion is a discontinuity of the skin exhibiting incomplete loss of the epidermis a lesion that is moist, circumscribed, and usually depressed.
(10) Ulcer: An ulcer is a discontinuity of the skin exhibiting complete loss of the epidermis and often portions of the dermis and even subcutaneous fat.
(11) Fissure: A fissure is a crack in the skin that is usually narrow but deep.
Comparison of skin lesions(12) Telangiectasia: A telangiectasia represents an enlargement of superficial blood vessels to the point of being visible.
(13) Burrow: This appears as a slightly elevated, grayish, tortuous line in the skin, and is caused by burrowing organisms.
Secondary Skin lesions:
(1) Scale: It is dry or greasy laminated masses of that represent thickened stratum corneum.
(2) Crust:It is a dried serum, pus, or blood usually mixed with epithelial and sometimes bacterial debris.
(3) Lichenification: The epidermal thickening characterized by visible and palpable thickening of the skin with accentuated skin markings.
(4) Excoriation: A punctate or linear abrasions produced by mechanical means (often scratching), usually involving only the epidermis, but commonly reaching the papillary dermis.
(5) Imduration: Dermal thickening causing the cutaneous surface to feel thicker and firmer.
(6) Atropy: It refers to a loss of tissue, and can be epidermal, dermal, or subcutaneous. With epidermal atrophy, the skin appears thin, translucent, and wrinkled.Dermal or subcutaneous atrophy is represented by depression of the skin.
(7) Maceration: It is softening and turning white of the skin due to being consistently wet.
(8) Umbilication: Formation of a depression at the top of a papule, vesicle, or pustule.