102. Skin Rash/Dermatitis (Petechia, etc)

Question 1

http: //www.pediatrics.wisc.edu/education/derm/text.html
http: //patient.info/health/skin-rashes

Describe the following skin rashes:
purpura?
Petechiae?
ecchymoses?

Answer 1

Reddish-purple lesions which do not fade with pressure (called purpura):

THEY DO NOT FADE WITH PRESSURE!!

• ——If less than one centimetre across then these are called petechiae
• ——If more than one centimetre across then they are called ecchymoses

Question 2

give the aetiology of purpura/petechiae/ecchymoses?

Answer 2

Purpura- bleeding under the skin

—result from disruptions in vascular integrity (trauma, infection, vasculitis, collagen disorders) or

—-may be due to abnormalities in primary or secondary hemostasis (thrombocytopenia, abnormal platelet function, clotting factor deficiency, or abnormal clotting factor function

These are dark red or purple and don’t fade with pressure.

meningococcal infection

common causes include injury to the skin or repeated coughing. (whooping cough)

serious common causes include liver disease.

Drug induced Vasculitis —sulfonamides (folic acid synthesis), penicillins, chloral hydrate, and phenytoin

vitamin C deficiency & impaired collagen deficiency

Less common causes include vasculitis (eg, Henoch-Schönlein purpura) or a low level of platelets in your blood (eg, idiopathic thrombocytopenia purpura).

Question 3

What skin conditions often cause itching?

Answer 3

Dry skin.
Eczema.
Contact dermatitis.
Urticaria.
Lichen planus.
Psoriasis.
Folliculitis.

Question 4

What are the common causes of skin rashes if:

red- erythematous but not scaly

Redness of the palms?

Answer 4

Cellulitis (skin infection).
Urticaria (allergic reaction).
Reaction to a medicine you are taking.
Burns.
Viral rashes - eg, measles or German measles (rubella).
Vasculitis (inflammation of blood vessels, which may occur with various illnesses, including rheumatoid arthritis).

Erythema nodosum.

Redness on the palms of your hands may be caused by liver disease, pregnancy or an overactive thyroid gland (hyperthyroidism).

A red rash may occasionally be due to an inflammatory condition called systemic lupus erythematosus, especially if it is on the cheeks.

Question 5

What are the common causes of skin rashes if:

red- erythematous & scaly

Answer 5

Psoriasis.
Eczema.
Seborrhoeic dermatitis (in adults) or cradle cap in babies.
Fungal skin infection, such as athlete's foot, tinea cruris (groin), ringworm, scalp ringworm or infection with candida.
Pityriasis rosea.
Pityriasis versicolor.
Lupus erythematosus.
Lichen planus.

Question 6

red flags for a skin rash?

Answer 6

The rash doesn’t quickly disappear.
patient feels unwell.
The rash does not fade with pressure (the best way to test this is to press a glass gently against the rash to see if it fades).

Question 7

Describe a macule?

and some examples of causes of macules?

Answer 7

A macule is a change in the color of the skin. It is flat, if you were to close your eyes and run your fingers over the surface of a purely macular lesion, you could not detect it. A macule greater than 1 cm. may be referred to as a patch.

Red macules -reaction to a medicine or a viral rash - such as measles or rubella - as well as other causes.

brown macule- mole , melanoma.

white macule- vitiligo

dark red or purple and does not fade when you put pressure on it then it is a purpura

Question 8

Describe a papule?

give examples?

Answer 8

Papules- A papule is a solid raised lesion that has distinct borders and is less than 1 cm in diameter. Papules may have a variety of shapes in profile (domed, flat-topped, umbilicated) and may be associated with secondary features such as crusts or scales.

papule may become confluent and form plaques- most commonly psoriasis

Common causes -acne,

viral wart, seborrhoeic wart,

molluscum contagiosum,

scabies,

insect bites

skin tags.

Other causes include psoriasis.

Question 9

Describe a nodule?

Give examples?

Answer 9

A nodule is a raised solid lesion more than 1 cm. and may be in the epidermis, dermis, or subcutaneous tissue.

Common causes of a nodule include a sebaceous cyst, lipoma, skin cancer, or a wart.

Other causes include rheumatoid nodules (associated with rheumatoid arthritis) and Heberden’s nodes (associated with osteoarthritis).

Question 10

Describe a blister?

Answer 10

Skin inflammation, including reactions to medicines, contact dermatitis, eczema. Eczema on the legs may be caused by varicose veins (varicose eczema).

Diseases of the immune system - eg, bullous pemphigoid.

Viral infections - eg, chickenpox, hand, foot and mouth disease.

Skin infection: a germ (bacterial) infection with impetigo or viral infection with herpes simplex (cold sores or genital herpes) or herpes zoster (shingles).

Rarer causes include pemphigus and pemphigoid.

also BURNS
FRICTION or rubbing

Question 11

Describe vesicle, bullae, pustule?

Answer 11

VESICLE

Vesicles are raised lesions less than 1 cm. in diameter that are filled with clear fluid.

BULLAE

Bullae are circumscribed fluid-filled lesions that are greater than 1 cm. in diameter.

PUSTULE

Pustules are circumscribed elevated lesions that contain pus (leukocytes) . They are most commonly infected (as in folliculitis) but may be sterile (as in pustular psoriasis)

Question 12

Describe Wheal?

Answer 12

A wheal is an area of edema in the upper epidermis.

Question 13

Describe a scar?

Colour? why?
Keloid scar?

Hypertrophied scar?

Answer 13

an abnormal formation of connective tissue implying dermal damage

scar- initially they are thick and pink- in time become white

—–Keloids are firm, rubbery lesions or shiny, fibrous nodules, and can vary from pink to the colour of the patient’s flesh or red to dark brown in color.

——It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1.

• —A keloid scar is benign and not contagious, but sometimes accompanied by severe itchiness, pain
• —they are seen 15 times more frequently in highly pigmented ethnic groups than in Caucasians

——-hypertrophic scars, which are raised scars that do not grow beyond the boundaries of the original wound..

Question 14

describe the difference between primary and secondary skin lesions?

http://www.pediatrics.wisc.edu/education/derm/text.html

Answer 14

primary-macule, patch…..papule, nodule….vesicle, bullae, pustule…wheal…burrow….

secondary- scale, crust, atrophy, ulcer, keloid, erosion, fissure, excoriation, scar esher

Question 15

describe some patterns and distributions?

Answer 15

annular, discrete, clustered, confluent, dermatomal, follicular, multiforme

Question 16

describe the difference between scaling and crusting?

Answer 16

Scale consists of flakes or plates that represent compacted desquamated layers of stratum corneum. Desquamation occurs when there are peeling sheets of scale following acute injury to the skin.

Crusting is the result of the drying of plasma or exudate on the skin. Please remember that crusting is different from scaling. The two terms refer to different phenomena and are not interchangeable. One can usually be distinguished from the other by appearance alone.

Question 17

Describe the relevant history to be taken from the patient regarding a skin rash?

Answer 17

relevant history should be taken in relation to
occupational and environmental factors

• Where? Site of initial lesion(s) and subsequent distribution
• How long? Has condition been continuous or intermittent?
• Prognosis—Is it getting better or worse?
• Previous episodes—How long ago? Were they similar? Have
there been other skin conditions?
• Who else? Are other members of the family affected? Or
colleagues at work or school?
• Other features—Is there itching, burning, scaling, or blisters?

Any association with drugs or other illnesses?
• Treatment—By prescription or over the counter? Have prescribed treatments actually been used