Bullous and Vesicular Rashes Flashcards
Vesicle vs bullae
Vesicles is less than .5 cm and filled with clear…bullae is larger
Etiology/epidemi
HSV1/2
Priamry HSV
Latent infections
HSV2 noromally genital
HSV1 usually as a child inovling mouth, lips, or eyes…via direct contact with skin lesions or secretions
Primary can be asymptomiatic…if there are sx, then fever, LAD, and fatigue
Latent is common…reacivation in sensory or autonomic gnaglia….prodrome of systemic sx and paresthesia/tingling/pain at future site of rash
Herpes simplex
Appearance Location Sx Distribution Dx
1-2 mm vesicles with an erythematous base…clustered together
Any cutanoues or mucocutaneous site but common on face
Pain and sometimes pruritic rash
Gingivostomatisis, herpetic whitlow (base of fingernail), genital
Often cliincal…can use HSV culture and PCR
HSV culture
PCR
Tzank smear
Driect AB test
Sensitivity depends on amount of virus collected….not super accurate
More snesitive and very specific…preffered**
Less sensitivie than culture…look for multinucleated giant cellls…rapid results**
Detects with high sensitivity but takes 48 hours
Tx of herpes simplex
Most do NOT require tx
Tx is best when early…acyclovir, valacyclovic, famciclovir
Acyclovir is converted by thymidine kinase (viral) to acyclovir monophosphate…then converted by host cell kinases to acyclovir triphosphate…inhibits and inactiveates viral DNA polymerase
Varicllea Etiology/epi
Appearance
Distribtuion
Doulbe stranded DNA virus
Contagious via secretions and droplets
contagious 2 days prior and until last crop of vesicles crusted
Incubatioin is 2 weeks
Clear vesicle on an erythematous base…may appear in crops that eventually become pustules and crust over
Begin on scalp and trunk…spread centrifugllary…unique is that lesions at varying stages of development**
Varciella sx, complications, diagnosis, tx
Low grade fever and malaise with pruritis
Staph and strep superinfection of skin (kids)…pneumonia by group A strpe in older
Clinical
Usually supportive iwth lotions and antihistmaines…oral acyclovir can decrease if tstarted early…only use if older than 12
Herpes zoster epi. appearnace, distribution
Reactivation of latent VZV virus in sensory nerve root ganglia…older
Initially erythematous that becomes grouped vesicles…similar to varicella, can become pustules before rupturing and crusting
Unilateral dermatomal…thoaric most comomn
Herpes zoster
Sx, diagnosis, tx
Pain, pruritis, paresthesia may precede…then grouped vesicle frorm for 3-5 day…crust formation forr 2-3 weeks with malaise and maybe mild fever
Clinical diagnosis
If tx with first 72 hours, can help…tx if close to eye, immunocomprosmised, or new lesions beyond first few days
Dermatitis herpetiformis
Epi, appearance, distribution
Majority have celiac dz
Grouped erythematous papulovesicles
Extensor syrfaces (extremities, back buttocks, and scalp)
Dermaitits herpitformis dx and tx
Skin biopsy shows neutrophil rich subepidermal blister and deposition of IgA in dermal papillary tips
Diaminodiphenyl sulfon - antibio
Hand foot mouth
Epi Appearance Dist Sx Dianogis Tx
Coxsackievirus
4-6 day incubation peroid
Vesicle with erythematous base
Palsm, soles, oral mucosa
Fever or malaise and painful lesions
Clinical
Hydration
Allergic contact dermatitis
Epi/appearance
Delayed-type hyeprsnesitivyt rxn…activiation of T cells by a hapten that leads to inflam
Vesicles and blister formation predominant in plants…less potent could produce scaling and lichenification
Allergic contact derm distr, sx, dx, tx
Areas of contat
Acute onset of intensely pruritic and exudative dermatitis
Clinical diagnosis…patch testing if unclear
Avoid contact and GCs
Pemphigus vulagirs epi/appearance/distr/sx/dx/tx
Autoantibody mediated of desmosomes…AABs against desmogleins…results in detachment of skin and mucous membranes
Flaccid blisters on non-inflamed skin with weeping and denuded
Oropharyngeal erosions common
Skin biopsy with direct immunofluroence sees IgG on keratinocytes
corticosteroids
