Skin Lesions are the anomalies or findings that are not normally seen in a normal individual and indicates towards some sort of underlying disease or pathology.
Skin leasions can be found over the epidermis , dermis or mucosal surfaces anywhere in the whole body surface present in direct contact to external environment.
These lesions can be divided into three categories :-
1. Primary Skin Lesions
2. Secondary Skin Lesions
3. Special Lesions
1. PRIMARY SKIN LESIONS :-
These are the initial or non-modified lesions. These lesions can be furthur classified into –
a) Flat , Non Palpable lesions ; when size is less than 1 cm then it’s called Macule if larger then it’s a patch.
b) Circumscribed , solid , raised lesions ; when size is less than 1 cm then it’s called Papules , when larger than 1 cm it’s reffered as plaques , if the lesion also have depth in it then it’s named as a Nodule.
c) Clear fluid filled lesion ; when size lesser than 1 cm it’s called as Vesicles and if larger then it’s called Bulla.
d) Pus filled lesion ; when smaller called as Pustule , if larger and deeper then called An Abscess.
e) RBC extravasation over (Skin or Membrane).
If less than 2 mm called as Petechiae , if between 2 mm to 1 cm named as Purpura , if larger then named as Echymoses .
f) Wheal ; is the term given to itchy , erythematous ,Transient evanescent plaque .
2. SECONDARY SKIN LESIONS :-
When the primary lesion gets modified either by Treatment , Scratching or evolution of diseases.
a) Scale ; visible exfoliation of stratum corneum
b) Crust ; Dried exudate such as Pus / Blood / Serum on skin surface
c) Erosion ; Focal or Complete loss of epidermis.
d) Ulcer ; Loss of epidermis alongside partial or total loss of dermis and Molecular Death of the involved layers.
e) Fissure ; Linear deep clefts or Cracks on the skin.
3. SPECIAL SKIN LESIONS :-
These are lesion seen only in certain kind of disease or disorders .
a) Target Lesion – seen in case of Erythema Multiforme .
b) Burrows – these are seen in individuals infected by Scabies as the parasite creates these burrows and serpigenous tunnels as their habitat over the skin.