Ch. 14 - Generalized Erythema Flashcards
What must a PA primarily focus on in order to correctly diagnose generalized erythema?
a complete history and physical with special attention to sites of skin involvement
What are the two most common eruptions for drug reactions?
- hives
2. mobilliform (more common than hives)
What appears as a generalized eruption of erythematous macules and papules, often confluent in large areas?
mobilliform
Which antibiotics are common offenders in drug eruptions?
- beta-lactams (penicillins, cephalosporins)
2. sulfonamides-trimethoprim-sulfamethoxazole
Which diuretics are common offenders in drug eruptions?
- furosemide
- hydrochlorothiazide
- both contain a sulfonamide
Approximately ___% of all medical inpatients experience drug-induced skin reactions.
2%
T/F: The onset of a drug-induced morbilliform eruption is immediate upon initiation of the drug.
FALSE (onset begins within several days to as long as a week after initiation)
What are the factors that a PA should consider when a patient that is on several medications presents with a drug eruption?
you should suspect drugs that are:
- new (started within 1 wk of the rash)
- frequent offenders
How can you differentiate between a viral exanthem and a drug eruption?
a drug eruption is much more erythematous, more confluent, and more pruritic
How can you differentiate between a toxic erythema and a drug eruption?
toxic erythemas have:
- ‘sandpaper-like’ texture
- mucous membrane involvement
- the presence of fever
- a focus of infection or presence of lymphadenopathy
What is the difference between a generalized erythema (drug eruption) & a chronic exfoliative erythroderma?
chronic exfoliative erythroderma has prominent desquamation
The presence of what in the infiltrate is an important clue suggesting a drug-related cause of generalized erythema?
eosinophils
What is the time required for total clearing of a drug eruption?
usually 1-2 weeks
What is a potential consequence of continuing the offending drug?
worsening of the rash
What is a form of generalized erythema that is caused by hematogenous dissemination of virus to the skin, in which a vascular response is elicited?
viral exanthem
What are the major viruses that are most often associated with exanthems?
- Rubeola (Measles)
- Rubella (German Measles)
- Herpesviruse type 6 (Roseola)
- Parovirus B19 (erythema infectiosum)
- Enteroviruses (ECHO & coxsackievirus)
What is the most common viral exanthem in children aged less than 2 years?
Roseola
Which viral exanthem occurs in young school-aged children, often in epidemics?
‘fifth’ disease (erythema infectiosum)
What is the prodrome of measles characterized by?
THE 3 C’S:
- Cough
- Coryza (cold symptoms)
- conjunctivitis
T/F: In patients with infectious mononucleosis, ampicillin increases the likelihood of rash from 3% to nearly 100%.
TRUE
How does the rash present typically in measles & German measles?
Begins on the head (behind the ears in measles) and proceeds to involve the trunk & extremities.
- in measles, individual lesions tend to become confluent on the face & trunk but remain discrete on the extremities.
How does roseola present clinically?
rose-red macules and papules develop primarily on the trunk & proximal extremities.
Which viral exanthem characteristically begins with red cheeks that have a ‘slapped’ appearance followed by a net-like erythema on the trunk & proximal extremities?
erythema infectiosum
What is characteristic of measles and often precede the rash?
koplik’s spots
What are found on the buccal mucosa and appear as tiny gray-white papules on an erythematous base?
koplik’s spots
In which viral exanthem does fever subside just before the rash appears?
Roseola
How is viral exanthem differentiated from Rocky Mountain spotted fever?
Rocky Mountain spotted fever starts distally (hands & feet) & becomes more purpuric as it progresses
What is the most serious complication that can arise from measles?
encephalitis
What is the most important complication of rubella?
congenital rubella syndrome
How does the virus gain entry to the body in all the viral exanthems?
through the upper respiratory tract (rubella & rubeola) or GI tract (enteroviruses)
What is an autoimmune disorder in which virtually any kind of skin lesion can occur, including macules, papules, plaques, bullae, purpura, subcutaneous nodules, and ulcers?
systemic lupus erythematous (SLE)
How does SLE present clinically?
an erythematous rash often with a violaceous hue; a malar rash with a “butterfly” appearance
The American Rheumatism Association states that a pt. is diagnosed with SLE if they have 4 or more criteria. What are the criteria?
- Malar rash 7. renal disorder
- Discoid rash 8. neurologic disorder
- photosensitivity 9. hematologic disorder
- oral ulcers 10. immunologic disorder
- arthritis 11. antinuclear disorder
- serositis
How is SLE differentiated from dermatomyositis?
Periungual erythema with telangiectasia is virtually diagnostic of dermatomyositis
If a butterfly rash is present how can a PA differentiate between SLE & seborrheic dermatitis?
Seborrheic dermatitis has fine yellowish scale, involvement of the nasolabial folds, and coexistence of a scaling rash on the scalp, behind the ears, on the eyebrows, & presternal area
What are the lab screening tests for SLE?
CBC, platelet count, UA, & ANA
What is a generalized erythema that is a cutaneous response to a circulating toxin?
toxic erythema
What are 4 types of toxic erythema?
- scarlet fever
- staphylococcal scalded skin syndrome (SSSS)
- toxic shock syndrome
- kawasaki syndrome
Who is at highest risk for SSSS?
neonates (because of decreased toxin clearance by kidneys & lack of antibody to to the toxin)
Except for toxic shock syndrome, toxic erythemas occur most often in _____.
children
What are the characteristics of toxic erythema seen on physical examination?
- sandpaper-like erythema
- accentuated in flexural folds
- followed by desquamation
Mucous membrane involvement accompanies all toxic erythemas except ____.
SSSS (staph. scalded skin syndrome)
How is toxic erythema differentiated from toxic epidermal necrolysis?
toxic epidermal necrolysis has blistering that is subepidermal rather than intraepidermal
What organism is found in pts. with scarlet fever?
Group A streptococci
Striking mucous membrane involvement & lymphadenopathy in a child who appears seriously ill are key features of what toxic erythema?
Kawasaki syndrome
In pts. with toxic erythema, cultures should be obtained from what potential bacterial reservoris?
- throat
- skin
- vagina
- blood
What is the course of scarlet fever?
complete recovery within 5-10 days
T/F: In all toxic erythema disorders, post-inflammatory desquamation usually occurs in 1-2 wks.
TRUE
the toxins involved in toxic erythema act as ____ that directly activate T cells.
superantigens
T cell activation in toxic erythema causes the release of massive amounts of which cytokines?
- TNF-alpha
- IL-1
- IL-6
T/F: Scarlet fever can recur if repeated streptococcal infections occur.
FALSE (scarlet fever DOES NOT recur because of specific antitoxin Abs that are formed from the 1st episode)
What is SSSS caused by?
a toxin produced by phage group II S. aureus
What is known as a generalized, inflammatory skin condition involving more than 90% of the skin surface area?
erythroderma
What are the causes of erythroderma?
- primary skin dz
- med. rxn
- rxn. to underlying malignancy
- idiopathic
Which generalized erythematous skin disorder is a exfoliative erythroderma with palpable lymphadenopathy?
Sezary Syndrome
