1. Dermatologic Manifestations of Infectious Diseases
Jessica Newman, DO
Division of Infectious Diseases

2. Doctor, I have this rash…

3. Other characteristics
Skin lesions - terms
Type of skin lesion
Raised
Flat
Depressed
Papule
Macule
Erosion
Plaque
Patch
Ulcer
Nodule
Erythema
Atrophy
Cyst
petechiae 
Striae
Wheal
Burrow 
Scar
Horn
Other characteristics
Shape
round, oval, annular, reticulated, linear, serpiginous, umbilicated
Color of skin lesion
white (leukoderma, hypomelanosis), red/pink (erythematous), violaceous (vascular, ecchymotic)
Consistency
soft, firm, fluctuant
Arrangement
Grouped
herpetiform/zosteriform, arciform, linear, serpiginous,
Disseminated
scattered discrete lesions or diffuse involvement
Distribution
Extent
isolated, localized, generalized
Pattern
symmetrical, exposed areas, intertriginous, including palms/soles

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5. Classification/type of lesion
Raised
Flat
Depressed
Surface Change
Fluid-Filled
Vascular
Papule
Macule
Erosion
Scale
Vesicle
Petechiae
Plaque
Patch
Ulcer
Crust
Pustule
Purpura
Nodule
Erythema
Atrophy
Excoriation
Bulla
Telangiectasia
Cyst
Striae
Fissure
Furuncle
Infarct
Wheal
Burrow 
Eschar
Abscess
Scar
Lichenification 
Horn
Notes – can “google image” additional examples if not described below:
Raised -
A papule is a solid, elevated lesion less than 0.5 cm in size in which a significant portion projects above the plane of the surrounding skin
Plaque is plateau-like and larger than a papule (may be confluence of papules)
Nodule is > 0.5 cm and can extend under the skin
Flat:
Macule = spot (small) – patch is larger
Erythema = redness
Surface change:
scale– excess skin (stratum corneum) layers
Crust - fluid dried on surface
Excoriated – scratch
Fissure – deep crack
Fluid-filled:
Vesicle is filled with clear fluid; pustule with opaque (pus) – size <0.5 cm
Bullae is > 0.5 cm

6. Approach to Dermatologic Diagnosis
Initial clinical impression (by history/systemic examination)
Classification/type of lesion
Shape (& color) of individual lesions
Consistency and feel of lesion
Arrangement of multiple lesions
Distribution of multiple lesions
Anatomic components of the skin primarily affected

7. Shape (description) of lesions
ulcer
crust
papule
vesicle
bullae
nodule
macule
plaque
pustule
Fitzpatrick's Dermatology in General Medicine, 7th Edition

8. Describe the dermatologic condition
CC: Rash
Describe the dermatologic condition
Plaques
Circular/irregular shape
Pink
Smooth
Randomly dispersed
Superficial

9. Skin Structure
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10. Superficial primary skin infections
Superficial dermatoses, erythrasma, pyoderma, cellulitis, fasciitis
Tinea corporis –
Patch, oval, pink-red (erythematous), scaling
Cutaneous candidiasis –
Plaque, circular/irregular, erythematous, with mild scaling and erythematous satellite papules

11. Primary Skin Infection
Deeper dermis and subcutaneous fat
Cellulitis

12. Erysipelas
Infx with beta-hemolytic streptococci – involves Upper dermis and lymphatics

13. Streptococcal infections
GAS Scarlet Fever
GAS Toxic shock syndrome
Erythroderma with desquamation
Scarlet fever (also known as ‘scarlatina’) is a diffuse erythematous eruption that generally occurs in association with pharyngitis. Development of the scarlet fever rash requires prior exposure to S. pyogenes and occurs as a result of delayed-type skin reactivity to pyrogenic exotoxin (erythrogenic toxin, usually types A, B, or C) produced by the organism.
The rash of scarlet fever is a diffuse erythema that blanches with pressure, with numerous small (1 to 2 mm) papular elevations, giving a "sandpaper" quality to the skin. It usually starts on the head and neck and is accompanied by circumoral pallor and a strawberry tongue. Subsequently the rash expands rapidly to cover the trunk followed by the extremities and ultimately desquamates the palms and soles are usually spared. The rash is most marked in the skin folds of the inguinal, axillary, antecubital, and abdominal areas and about pressure points. It often exhibits a linear petechial character in the antecubital fossae and axillary folds, known as Pastia's lines

14. Meningococcemia

15. Purpura Fulminans Meningococcemia Capnocytophaga sepsis
Inherited protein C deficiency 15

16. Varicella Zoster Virus Primary infection - Chickenpox
DNA
Member of the Herpes family
VZV prodrome:
Primary infection: Fever, malaise, loss of appetite, sore throat
Zoster: localized burning pain
Rash
Primary: Papules->vesicle->crust; begins centrally and moves outward
Zoster: dermatomal

17. Herpes Zoster
Vesicles on erythematous base

18. “Poxes” Smallpox Chickenpox
Variola virus; a DNA orthopoxvirus within the Poxviridae family
Lesions are all in same stage
Double-stranded, linear DNA herpesvirus
Lesions appear in a variety of stages
Vesicle

19. Rocky Mountain Spotted Fever19

20. Rocky Mountain Spotted Fever
R. rickettsii infects endothelial cells causing vasculitis
Rash
Typically occurs 2-4 days after fever
Begins ankles, wrists and forearms, palms and soles, then spreads centrally
Evolves to petechial lesions
Organism is not evident on blood smears

21. Ehrlichiosis
Infects monocytes and replicates in cytoplamic membrane-bound vacuoles
Rash
Much less common (30-40% HME and 1/40 in HE) appears at approx 5 days
Can be maculopapular, macular or petechial

22. “Maculopapular rash”…
Henoch-Schönlein purpura
Acute HIV
Secondary syphilis
Measles 22

23. Secondary Syphilis

24. Parvovirus B19 Erythema Infectiosum or Fifth Disease

25. Sporotrichosis
An ulcerated nodule is seen on the thumb, with proximal lymphangitic spread represented by subcutaneous nodules
Fitzpatrick’s Dermatologic in General Medicine, 7th Ed 25

26. Blastomycosis 26

27. Histoplasmosis
PAS-stained smear showing degenerating H. capsulatum organisms on a necrotic background 27

28. Mycobacterium marinum
Verrucous, violaceous plaque with central spontaneous clearing occurring at the site of an abrasion sustained in a fish tank. The lesion was caused by M. marinum. 28

29. Disseminated Cryptococcus Infection

30. Primary Skin Disorders
Psoriasis
Eczema

31. Rheumatic disease/Autoimmune disease
IgA vasculitis
Systemic Lupus erythematosus

32. Cancer-related Gottron’s papules Tripe Palm Heliotrope rash
Heliotrope rash
Dermatomyositis
Acanthosis nigricans

33. Want to learn more about dermatology?
Fitzpatricks Color Atlas and Synopsis of Clinical Dermatology, Eighth Edition / Edition 8 by
Klaus Wolff,
Richard Johnson