Topic 9 - Primary skin lesions. Flashcards
Definition of primary skin lesion:
The initial eruption that develops spontaneously as a direct reflection of underlying disease. They may appear quickly and then disappear rapidly
Name primary lesions:
- macule,patch
- papule, plaque
- pustule, abscess
- vesicule, bulla
- cyst
- wheal/urtica
- nodule
(8. tumour) - Tuber
- Angioedema
Defintition of macule:
a circumscibed, nonpalpable spot up to 1 cm in diameter and characterized by a change in the color of the skin
Definition of patch:
a macule larger than 1 cm in size
What is a macule or a patch caused by?
Can be: Pigment or vascular
Type of pigment causing macule or patch:
Melanin pigment
Local haemorrhages
Examples of melanin pigment:
melanoderma, naevus, vitiligo,
postinflammatory
hypo-hyperpigmentation
Examples of local haemorrhages:
petechia (pinpoint)
purpura (bleeding into skin)
vibex (line-form)
ecchymoses, suffusio (>1 cm)
sugillatio
Two main categories of vascular patch or macules:
Functional or anatomical
Functional vascular patch or macules:
Can be wither active or passive hyperaemia
Anatomical vascular patch or macules:
Can be either hyperplastic or aplastic
Definition papula:
a small solid elevation of the skin up to 1 cm in diameter that can always be palpated as a solid mass. Many papules are pink or red swelling produced by tissue infiltration or inflammatory cells in the dermis, by intraepidermal and
subepidermal edema or by epidermal hypertrophy. They may involve or not involve hair follicules
Examples of papula:
erythematous papules
In which diseases can we see erythematous papules?
- scabies
- FAD
- superficial bacterial folliculitis!!
- allergic contact dermatitis
Definition of plaque:
a larger, flat-topped elevation formed by the extension or coalition of papules
Give an example of plaque:
eosinophil granuloma complex in cats
Definition of a nodule:
a circumscribed, solid elevation greater than 1 cm in diameter that usually extend into deeper
layers of the skin
Definition of tuber:
Inflammatory elevation of papillary zone of
skin or mucous membrane with different shape and size
What causes a nodule?
Result from massive
infiltration of inflammatory or neoplastic cells into the dermis or subcutis.
Deposition of fibrin or crystalline material also
produces nodules
Definition of a tumour:
a large mass that may involve any structure of the skin or subcutaneous tissue. Most tumors are neoplastic or granulomatous in origin
Definition of wheal/urtica:
a sharply circumscribed raised lesion
consisting of edema that usually appears and disappears
within minutes or hours
Definition of Angioedema:
A huge hive of a distensible region such as the lips or eyelids
Definition of a vesicle:
a sharply circumscribed elevation of the epidermis filled with clear fluid.
Can be intraepidermal or subepidermal
Lesions up to 1 cm in diameter
why does vesicles occur?
They occur in viral and autoimmune dermatoses, or in dermatitis caused by irritants
Rarely seen in dogs and cats
Definition of Bullae:
Blisters larger than 1 centimeter wide
Definition of a cyst:
an epithelium-lined cavity containing fluid or a solid material. It is smooth, well-circumscribed, fluctuant to solid mass.
Definition of a pustule:
a small, circumscribed elevation of the epidermis that is filled with pus.
Their color is
usually yellow but may be green or red.
Pustules may be
intraepidermal, subepidermal and follicular
Definition of abscess:
a demarcated fluctuant lesion resulting from a dermal or subcutaneous accumulation of pus. The pus is not visible on the
surface of the skin until it
drains to the surface.
Abscesses are larger and
deeper than pustules
Name lesions that can be both primary and secondary:
- Alopecia
- Scale
- Crust
- Follicular casts
- Comedo
- Pigmentary abnormalities
Definition of alopecia:
loss of hair and may vary from partial to complete
Can be primary or secondary
Primary alopecia:
due to endocrin disorders, follicular dysplasias
Secondary alopecia:
due to trauma or inflammation
Definition of scale:
an accumulation of loose fragments of the horny
layer of the skin (cornified cells).
Can be primary or secondary.
Look of scale:
Flakes vary greatly in consistency; they can appear branny, fine, powdery, flaky, platelike, greasy, dry, loose, adhering, or „nitlike”. The color varies from white, silver, yellow, or brown to gray
Primary scales:
Due to color dilution alopecia
primer idiopathic seborrhoa,
follicular dysplasia
Secondary scales:
Due to chronic inflammation
Definition of crust:
is formed when dried exudate, serum, pus, blood, cells, scales, or medications adhere to the surface.
Unusually thick crusts are found in hairy areas because the dried material tends to adhere
more tightly than in glabrous skin.
Have primary and secondary
Primary crusts:
Due to primary idiopathic seborrhea
Secondary crust:
Due to pyoderma, fly strike, pruritus
Definition of comedo:
pores or hair follicles that have gotten blocked and form a bump on your skin.
Have primary and secondary
Primary comedo:
Initial lesion of feline acne and may predispose the skin to other diseases
Which disease can primary comedo predispose to?
- bacterial folliculitis
- infection with Demodex and
dermatophytosis - vitamin A-responsive dermatosis
- Schnauzer comedo syndrome
- Cushing’s disease
- sex hormon dermatoses
- idiopathic seborrhea disorderes
Secondary comedo:
to seborrheic skin disease, to occlusion with greasy medications, or to the administration of systemic or topical corticosteroids
Definition of follicular cast:
an accumulation of keratin and
follicular material that adheres to the hair shaft extending above the surface of the follicular ostia
Have primary and secondary
Primary follicular cast:
- vitamin A-responsive dermatoses
- primary idiopathic seborrhea
- sebaceous adenitis
Secondary follicular cast:
demodectic mange and dermatophytosis
Definition of abnormal pigmentation:
skin coloration caused by a variety of pigments but most commonly melanin, which is responsible for many skin colors. Have both hypopigmentation and hyperpigmentation
Definition of hypopigmentation:
Loss of epidermal melanin. Have both primary and secondary, secondary due to postinflammatory changes.
Definition of hyperpigmentation:
increased epidermal and ,
occasionally, dermal melanin. Melanophages may be found in the superficial dermis.
Have primary and secondary, secondary due to postinflammatory changes, trauma
