Rash Flashcards
Immunologic – delayed type IV hypersensitivity reaction, occurring 7-14 days after drug has started, but can still occur even after drug discontinuation
Exanthematous drug eruption
Morbilliform rash. +/- low grade fever
Monomorphic (individual lesions look very similar to one another) macules and thin papules start on face + trunk & spread to extremities. + pruritic
(reaction typically limited to skin)
Exanthematous drug eruption
Tx of Exanthamous drug eruption
spontaneously resolves within 1-2 weeks, even with continuation of the culprit drug if necessary
Treatment = supportive for pruritis w/ topical corticosteroids and oral antihistamines
Preceded by prodrom of fever, malaise, + upper respiratory sx before onset of skin lesions.
Tender, dusky red, prupuric macules that progress to flaccid bullae and erosions (areas of necrosis)
Stevens Johnsons Syndrome /Toxic Epidermal Necrolysis
Onset between 1-3 weeks of drug initiation
Common drugs: allopurinol, anti-convulsants (lamotrigine, carbamazepine, phenobarbital, phenytoin), antibiotics, NSAIDs, and sulfa drugs
Stevens Johnsons Syndrome /Toxic Epidermal Necrolysis
Associated symptoms of Steven Johnson
Sx: fever, LAD, hepatitis, cytopenias
ny oral surface may be involved: + buccal, ocular, and genital mucosa >90%
+ Resp tract involvement ~25%
Dx between Steven Johnson and TEN
Amount of skin covered is generally what indicates diagnosis (indicating as amount of epidermal detachment of the body surface area):
<10% = SJS
10-30%: SJS-TEN
>30% = TEN
Mortality rate = 35% for severe cases of TEN à primarily from SEPSIS
Tx for Steven Johnson
Prompt discontinuation of causal drug is key – supportive care, use of IVIG is controversial.
Pathogenesis for atopic dermatitis
- Genetics: mutations in profilaggrin gene, responsible for ichthyosis vulgaris (genetic disorder resulting in severely dry skin) = large predisposing genetic factor
- Epidermal barrier dysfunction: ¯ essential fatty acids, fillagrin mutations, susceptibility to allergins, water loss
- Immunopathology = prototypic type II helper T cell disease (causing IL-4, IL-5, and IL-13; ¯ IL-2 and IFN-gamma)
- Defects in cell mediated immunity: susceptibility to viral, bacterial, and fungal infections of skin – majority of pts colonized with staph aureus
Onset in infancy typical, but delayed onset in adulthood can be seen. Occurs in setting of other atopic disorders including allergic rhino-conjunctivitis and asthma.
atopic dermatitis
Acute, Subacute and Chronic lesions seen in atopic dermatitis
Acute lesions: edematous, erythematous papules and plaques, and may ooze.
Subacute lesions: erythematous and scaly, may be crusted. ***less well defined than those of psoriasis
Chronic lesions: thickened with lichenification (exaggerated skin lines)
face most often affected (esp cheeks) & lesions are often exudative w/ sig oozing and crusting + extensor involvemnt (diaper area spared); impetigo as well
Infantile AD:
What is seen in Childhood AD:
What is seen in Adult AD:
involve flexures (antecubital + popliteal fossae) and some lichenification
similar, but may have evidence of habitual scratching and rubbing with chronic popular skin lesions – may be more resistant to treatment.
What does eczema herpaticum present like and how do we treat it?
*most common chronic inflammatory skin disease
**Rapid dissemintation of herpes simplex virus within areas of eczema, reffered to as eczema herpeticum, can complicate AD.
Treatment: topical corticosteroids (actively inflamed AD)
- avoid triggers, use bland emolients + use of lotions alot
What are some pharmaceutical options to treat atopic dermatitis?
- Topical calcineurin inhibitors (tacrolimus + pimecrolimus) can be used in place of lower strength topical corticosteroids, but efficacy for lichenified lesions = limited
severe / recalcitrant dz: phototherapy + immuno-suppressants.
- antihistamines = alleviate pruritis, esp sedating H1 antihistamines (diphen-hydramine, hydroxyzine)
Spread by contact with infected skin or clothing
very large ds DNA virus = poxvirus fam
Molluscum contagiosum:
Firm small, pink or flesh colored dome-shaped papules with central umbilication
– large eosinophilic inclusions in cytoplasm = viral ‘factories on histology
Histology of lesions include molluscum bodies
Who do we see moluscum contigoiusm in? How do we treat it?
most common in children,risk with atopic dermatitis and appears
Lesions persist and are more numerous in those with weakened immune systems
~7 weeks s/p expos
Most have complete clearing in 2-4 months
viral infection of a pre-existing dermatosus
most commonly caused by disseminated HSV infection in pts with atopic dermatitis
eczema herpeticum
sudden eruption of painul, edematous, crusted vesicles, pustules and erosions
+/- high temperature, malaise, LAD
eczema herpaticum
Tx for eczema herpaticum
requires IV acyclovir
Difference between Shingles and chicken pox
Chickenpox (varicella): d/t infection by varicella zoster virus = highly contagious disease. (incubation 11-20 days)
Shingles: caused by an eruption of latent varicella zoster virus (VZV). Occurs particularly in adults.