Infectious Disease Tutorial



Classic findings of pneumonia (with an open bronchus)

  • Inspection-may have reduced thoracic expansion on involved side
  • Palpation-increased tactile fremitus and reduced expansion by palpation
  • Percussion-dullness
  • Auscultation-bronchial(tubular)breath sounds, crackles and all of the vocal resonance signs(eg, egophony)are increased.

Cutaneous infections


Increased warmth, edema, and erythema of the skin with ill-defined borders.



Increased warmth, edema, and erythema of the skin with well-defined borders.



Vesicles overlying an erythematous base, in a dermatomal distribution. Hutchinson’s sign- Hutchinson’s sign is the finding of zoster at the tip of the nose, heralding herpes zoster ophthalmicus with the complications of keratitis/uveitis.


Cutaneous blastomycosis

The initial cutaneous lesion of blastomycosis is an inflammatory nodule that enlarges and ulcerates, often resembling pyoderma gangrenosum. Lesions evolve to verrucous or crusted plaques with sharply demarcated serpiginous borders.


Cutaneous leishmaniasis

Characterized by sores that usually start as papules or nodules and evolve into ulcers with raised borders and central crater. The ulcers may be covered by scab or crust.

Infective endocarditis

Osler’s nodes

Tender erythematous or violaceous subcutaneous nodules on the thenar and hypothenar eminences and pulps of fingers and toes.


Janeway lesions

Nontender erythematous or hemorrhagic macular lesions on the palms and soles.


Roth spots

Retinal hemorrhages with a central pallor, visualized on fundoscopic examination.


Conjunctival petechiae


Splinter hemorrhages

Linear brownmarks on the fingernails that resemble wood splinters.



Pain and resistance on extension of the knee starting with the hip and knee flexed at 90 degree with patient in the supine position



Reflex flexion of the hips and knees on passive flexion of the neck with the patient in the supine position.



Meningococcemia is associated with a petechial and purpuric rash.

Rheumatic fever

Erythema marginatum

Circular rash with pale pink center surrounded by raised erythematous borders, appearing on the trunk and extremities.



Painless subcutaneous nodules typically appearing over joints (eg, elbows, knuckles, knees,ankles).


Sydenham’s chorea

Jerking movements of the face, hands, and feet that are rapid and uncoordinated.


Mitral stenosis


Disseminated gonorrhea


Disseminated gonorrhea is characterized by a syndrome of fever, chills, pustular rash on the trunk and extensor surfaces of the distal extremities, and nonpurulent migratory oligoarticular inflammatory arthritis associated with tenosynovitis.Sometimes the rash is petechial and purpuric rather than pustular.




Primary syphilis is characterized by the presence of a painless genital ulcer that is usually round and firm.


Palms and soles rash

The rash of secondary syphilis is typically a nonpruritic papulosquamous rash often involving the palms and soles, associated with mucocutaneous lesions and generalized lymphadenopathy.

Strep throat

Tonsillar exudate


Palatal petechiae


Lyme disease

Erythema migrans

Erythema migrans describes a “target” rash, seen in the early stages of Lyme disease at the site of the tick bite.



Conjunctival suffusion.


Rocky mountain spotted fever

Rocky mountain spotted fever is associated with a skin rash characterized by small pink-colored macules involving the distal extremities, palms, and soles. 

Pott’s puffy tumor

Swelling of the forehead, indicating an underlying osteomyelitis of the frontal bone, usually the result of frontal sinusitis.

Cat scratch disease

Classic cat scratch disease (fever and regional lymphadenopathy lasting <7 days) is the most common clinical manifestation of Bartonella henselae infection.

Subretinal abscess.