Those strange words Dermatologists use - Little dictionary

Actinic disease: disease caused or worsened by sunlight.

Allergy, Allergen :  see dedicated factsheets.

Alopecia: lack or loss of hair. It can be localized or widespread; focal (a single patch) or multifocal; spontaneous

(hair falls for the disease) or self-induced (coat is damaged by external trauma such as scratching).

Autoimmune disease  : those in which the immune system rather than destroy external pathogens, is directed towards some normal component of the skin.

Biopsy: removal of a small sample of skin to perform a histological examination (but also cultures, PCR etc.).

Bulla: see vesicle, but larger.

Cultural examination: eg. bacteriological, mycological. A sample of hair or skin or other material is placed on a culture medium in order to isolate the pathogen.

Cyst: nodular lesion with an internal cavity lined with epithelium.

Comedone: so-called "blackhead". Hair follicle dilated and obstructed by a plug of keratin and sebum.

Cytology: through various techniques (swab, needle aspiration etc.) cells are taken from the affected skin. After being arranged on a slide and stained, they can be examined quickly with the microscope. Compared to histological examination is less precise but faster and easier to run.

Depigmentation: skin lighter in colour (white, gray) than normal.

Dermatitis: general term indicating inflammation of the skin.  As such it is not a diagnosis.

Dermatoses: general term indicating a non-inflammatory disease of the skin.

Dips : topical application of a drug diluted in water. Generally they must not be rinsed.

Follicular casts: scales surrounding a tuft of hair. They are a sign of disease affecting the hair follicle.

Follicular dysplasia: congenital condition of hair follicles that are malformed.

Ectoparasites: parasites living on\in the skin (eg. fleas, mites, ticks etc.).

Endocrine diseases: involving the endocrine glands, that is those producing hormones.

Eosinophilic diseases: eosinophils are white blood cells involved especially in parasitic and allergic diseases. Frequent in cats.

Epidermal collarette : residue of a hollow lesion (pustule, vesicle), after the top broke. It consists of an alopecic center and a squamous rim.

Erythema: redness of the skin. If you press it with a finger it becomes pale.

Excoriation: superficial injury, often linear, due to trauma or self-trauma (scratching).

Exudate :  pathological liquid, more or less dense, contained in a lesion or body cavity (eg. pus).

Fistula: opening to the outside of a nodule or plaque from which a pathological liquid is going out (eg. pus).

Folliculitis: inflammation of the hair follicles, the structures in which the hairs grow. The three most common causes are bacteria, Demodex mites and dermatophytes (fungi).

Granuloma: inflammatory lesion by which the body tries to isolate, to encapsulate a pathogen (eg. bacteria, fungi, foreign bodies).

Hyperkeratosis : thickening of the horny layer of the skin.

Hyperpigmentation: skin darker in colour (black, brown, bluish) than normal.

Hypersensitivity: synonymous with allergy.

Hypertrichosis: excessive growth of hair.

Hypotrichosis: hair reduction, in number or in length.

Lichenification: typical chronic lesion.  On the thickened skin, it's possible to see clearly the skin typical tracks.

Macula: flat area of skin with lighter or darker color.

Nodule: solid lesion, more or less circumscribed, with size greater than 1 cm. It can be intradermal or subcutaneous.

Papule: small raised skin lesion, often reddish. It tends to evolve towards other lesions (pustule, plaque).

PCR: Polymerase chain reaction. Molecular diagnostic technique capable of detecting small amounts of DNA or RNA of a pathogen (bacteria, viruses, etc.) in an organic sample.

Plaque: circumscribed area of ​​thickened, raised skin.

Prophylaxis: a synonym for prevention.

Pustule: small raised skin lesion, usually with yellowish apex, containing pus. In dogs and cats pustules break soon.

Scaling :  detachment from the most superficial part of the skin  of lamellae (scales, dandruff), generally whitish. If excessive, it is abnormal.

Scar: hairless area, usually whitish, shiny, residual of lesions that affected permanently the skin replacing it with fibrous tissue.

Seborrhea: a bit 'vague' term used to describe any situation characterized by excessive flaking or greasiness of the skin.

Self-limiting disease: that heals on its own.

Sensitivity testing : after isolating the pathogenic bacterium in a culture, various antibiotics are tested to understand which one works and which not.

Serological examinations: tests carried out on blood serum to diagnose infectious diseases.

Skin components: the skin is constituted, starting from the outside, from the epidermis (formed by a few layers of epithelial cells; without blood vessels), the dermis (vascularized, with support function) and the subcutis (containing the subcutaneous fat). Hair follicles are specialized structures in which hairs grow.

Skin glands  : Sebaceous glands and apocrine sweat glands: are associated to hair follicles and produce a secretion that helps to protect the skin and keep it hydrated and soft.  Eccrine sweat glands: in dogs and cats are found only in digital pads. Secrete sweat.

Skin scraping: diagnostic examination performed with a scalpel blade scraped on a lesion and then transferred onto a microscope glass in order to search for ectoparasites (eg mites).

Spot-on: pipette whose liquid is applied on the skin, usually between the shoulder blades.

Topical: drug for local use (eg. creams, spray, rinses etc.).

Trichogram: microscopic examination of hair shafts and roots. Plucking is the stripping of a tuft of hair for the trichogram.

Ulcer \ Erosion: loss of substance of the skin, superficial (erosion) or deeper (ulcer).

Vasculitis: inflammation of skin blood vessels (capillaries, arterioles).

Vesicle: small raised lesion containing a colorless liquid . In dogs and cats are rare.

Wheal:  flattened, slightly raised, circumscribed lesion.

Wood lamp: a source of ultraviolet rays used to identify Microsporum canis (agent of dermatophytosis). If the test is negative, however, one can not exclude the disease.