SKIN LESIONS IN
INFECTIOUS
DISEASES
ISLAM FARIS 119I1B
Macule
Common
Skin Lesions
In Infectious
process
papule
Purpura & Petechiae
Vesicle
Pustule
Nodules
Ulcers
Urticaria
Macule
A macule is a flat, distinct, discolored
area of skin less than 1 centimeter (cm)
wide. It doesn’t involve any change in
the thickness or texture of the skin.
Areas of discoloration that are larger
than or equal to 1 cm are referred to as
patches.
Macules can be a symptom of many
diseases often times alone isn't a
diagnostic factor, causes may be fungal
autoimmune and also infectious.
Papule
A papule is a raised area of skin tissue that’s
less than 1 centimeter around. A papule can
have distinct or indistinct borders. It can
appear in a variety of shapes, colors, and
sizes. It’s not a diagnosis or disease.
Papules are often called skin lesions, which
are essentially changes in your skin’s color or
texture. Sometimes, papules cluster together
to form a rash.
Potential infectious causes are
Shingles or Chickenpox, which is a viral
infection characterized by a painful rash and
blisters later on caused by the varicella zoster
virus
Epidemic Typhus
Small, pink macules, which
appear on the 4th to 6th day,
rapidly cover the body, usually in
the axillae and on the upper trunk
and not on the palms, soles, and
face. Later, the rash becomes dark
and maculopapular.
In severe cases, the rash becomes
petechial and hemorrhagic.
Maculopapular Rash
Being one of the most common skin
manifestations of infectious
conditions Maculopapular rashes
contain both Macules and Papule
throughout patches around the
body dependent on the causative
agent
Some Infectious causes:
Measles, Rubella, Syphilis, Endemic
Typhus, Zika, Smallpox, also
associated with rickettsial infections
such as Prowatzke and Q- Fever
Purpura & Petechiae (Meningococcal Infection)
Once the bacteria have invaded the
back of the nose and throat, they travel
through the bloodstream. As this
happens, the bacteria rapidly multiply
and produce toxins which travel around
the body causing damage to blood
vessels and organs. As the blood vessels
get damaged, blood starts to ‘leak’ into
the surrounding tissue, often causing
what looks like a ‘rash’ to appear on the
skin
Meningococcal Infection
This rash can be one of the clearest and most
specific signs of meningococcal meningitis
and septicaemia to recognise – hence why
you have probably heard of it. However,
meningococcal rashes can be extremely
diverse, and look different on different skin
types. The rate of progression can also vary
greatly.
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A petechial rash looks like pin-prick red
or purple spots on the skin, and can
resemble flea bites.
A purpuric rash looks more like
bruising, showing up as reddish-purple
areas on the skin.
The meningitis “rash” can start as a blanching
rash, but nearly always develops into a nonblanching red, purple or brownish petechial
rash or purpura, meaning it will not disappear
when pressed.
Vesicle
Small, clear, fluid-filled
blisters < 10 mm in
diameter. Vesicles are
characteristic of
● Herpes Infections
● acute allergic contact
dermatitis,
● and some
autoimmune
blistering disorders
(eg, dermatitis
herpetiformis).
Pustule
Pustules are vesicles that contain pus
Several viral infections can also lead to
pustules, including chickenpox, a highly
contagious infectious disease caused
by: Varicella Zoster virus, or VZV, and
smallpox, a very contagious and
potentially fatal disease caused by
Variola virus. Fungal infections, such as
dermatophyte infections (also known
as tinea) as well as thrush (an oral
infection due to Candida albicans) can
also cause pustules. Additionally,
pustules can develop in parasitic skin
infections, such as scabies, which is an
infestation of mites called Sarcoptes
scabiei that cause intense itching.
Bubo’s (Nodules)
Bubonic plague is a type of infection
caused by the Yersinia pestis (Y. pestis)
bacterium which is spread mostly by
fleas on rodents and other animals.
Humans who are bitten by the fleas
then can come down with plague.
Once the infection is established,
sudden onset of fever, chills, and
weakness is observed, followed by the
development of an acutely swollen
tender lymph node commonly called a
bubo later on the infection can cause
DIC (disseminated intravascular
coagulation) which causes necrosis
throughout sometimes develop into
Ulcers
Ulcers
Result from loss of the epidermis and at least
part of the dermis. Causes include venous
stasis dermatitis, physical trauma with or
without vascular compromise some
infectious causes can be
Leishmaniasis due to expansion of papule
into ulcerative plaque caused by infection
with L.Donavani
Dracunculiasis (Guinea worm) Ulcers
caused by the emergence of the worm
invariably develop secondary bacterial
infections, soon to be the second eradicated
disease by mankind after smallpox
Syphilis also known to cause ulcers after the
development of chancres
Etc…
Urticaria
Known as hives, weals, welts or
nettle rash – is a raised, itchy rash
that appears on the skin. It may
appear on one part of the body or be
spread across large areas.
considered one of the pre-icteric
symptoms of viral hepatitis
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Hep A,B & C
Epstein Barr
Herpes simplex
All may be causative agents thought
to be due to circulating immune
complexes although may be
disputed, also may be due to an
allergies from a circulating igE
attaching to mast cells
(Hives)
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YOU