Differential Diagnosis
Digital Lecture Series : Chapter 29
Dr. Saumya Panda
Professor,
Department of Dermatology,
KPC Medical College, Kolkata
CONTENTS
 Formulating the d/d
 Malar rash
 Occam’s razor
 Thickened nerves
 Fever with rash
 Bubo
 Arthritis, fever and rash
 Genital ulcer disease
 Dysesthesia without obvious
 Annular lesions
primary lesion
 Painful nodules
 Hypopigmented patch
 MCQs
 Photo Quiz
Differential diagnosis - Factors to consider
 Symptoms (e.g. fever, pain, pruritus)
 Duration and natural history ( acute, subacute, chronic, intermittent)
 Basic morphology (‘primary lesions’) (macules, patches, papules,
plaques, nodules, vesicles, bullae, pustules)
 Secondary morphology (scales, crusts, erosions, ulcers, scars)
 Arrangement (annular, linear, solitary, generalized)
 Topographical location (arms, feet, head)
 Colour (black, blue, brown, red, yellow)
 Laboratory findings
 Histopathology findings
Occam’s Razor
 Principle of problem-solving.
 Among competing hypotheses, the one with the fewest assumptions
should be selected.
 Other, more complicated solutions may ultimately prove correct,
but-in the absence of certainty - the fewer assumptions that are
made, the better for accurate diagnosis.
Fever with Rash
Fever & Rash
Viral infection
Measles
Rubella
Varicella
Erythema infectiosum
Roseola
Enterovirus infection
Infectious
mononucleosis
Dengue
Viral hepatitis
Other infections
Meningococcemia
Staphylococcemia
Scarlet fever
Typhoid fever
Pseudomonas bacteremia
Syphilis
Rocky mountain spotted
fever
Lyme disease
Bacterial endocarditis
Drug hypersensitivity
Penicillins
Sulphonamides
Quinolones
ATTs
Anticonvulsants
Thiazides
Miscellaneous
Serum sickness
Erythema marginatum
Erythema nodosum
SLE
Dermatomyositis
Allergic vasculitis
Pityriasis rosea
Viral Infections
Infections : Viral exanthems
Disease/
Incubation
Virus
Measles
(1-2 wks)
1st disease
Paramyxovirus
rubeola
Prodrome, Koplik’s spots , rash 4/ 5th day of
fever, cephalo-caudal, fades 5- 10 days,
complications: diarrhoea, pneumonia, SSPE.
Rubella
(2-3 wks)
3rd disease
Togavirus
rubella
50% subclinical, Mild prodrome ,
Forschheimer’s spots, rash begins on face and
spreads downwards; lymphadenopathy.
Clinical Features
Measles
Koplik’s spots :
 A prodromic viral enanthem of measles
manifesting 1-2 days before the rash.
 Characterized as clustered, white
lesions on the buccal mucosa (opposite
the lower 1st & 2nd molars).
Fever characteristics :
 Typically the fever continues increasing
in intensity till 4-5 days after onset.
Exanthem :
 Typically appears on the 3rd day of fever
and subsides with desquamation.
Measles Exanthem
Infections : Viral exanthems
Disease/
Incubation
Erythema
infectiosum
(2-3 wks)
5th disease
Exanthem
subitum
(5-15 days) 6th
disease
Virus
Clinical Features
Parvovirus B19
Mild / absent prodrome, 3 distinct, stages slapped cheek, generalised exanthem,
reticulate erythema , recurrent phase , no
lymphadenopathy, Complications:
polyarthropathy , gloves and stocking
syndrome.
HHV6, HHV7
Rash begins suddenly when fever subsides on
6th day, Pink almond shaped macules- neck
and trunk, no complications.
Erythema Infectiosum
Exanthem Subitum
 Roseola Infantum. Evolution of Signs and Symptoms.
 Pale pink macules may appear first on the neck.
 Numerous pale pink, almond-shaped macules.
Infections : Viral
Disease/
Incubation
Virus
Clinical Features
Non-specific
exanthem
(variable)
Entero, echo,
coxsackie virus
Morbilliform rash with fever, asymptomatic.
Occ urticarial, petechial vesicular, palms/soles
involved, confused with drug rash.
HFMD
(4-6 days)
Coxsackie virus
A16,
enterovirus 71
Mild prodrome, aphthae, small macules with
vesicular center and red areola, oval,
extremities and buttocks, complications : CNS,
pulmonary edema.
Hand Foot & Mouth Disease
HFM
Infections : Viral
Disease/
Incubation
Varicella
(14-16 days)
Virus
Clinical Features
Low grade fever, malaise, classical dew drops
Varicella-zoster on a rose petal, pleomorphic, centripetal,
complications : pneumonia, CNS, Reyes.
Herpes Simplex
HSV I & II
(2 -14 days)
Primary and recurrent episodes, fever,
malaise, lymphadenopathy, gingivostomatitis,
kaposi’s varicelliform eruption.
Varicella
Primary Herpes
Tzanck smear shows multinucleated
giant cells. Primary cases may be
severe, recurrent or secondary cases
are relatively asymptomatic, with
patients being mostly afebrile.
Infections : Viral
Disease/Incubation
Infectious
mononucleosis
Dengue
Chikungunya
Virus
Epstein Barr
Virus
FlavivirusDengue fever
virus
Chikungunya
virus
Clinical Features
Fever, pharyngitis, lymphadenopathy- triad palatal
enanthem, morbilliform rash, scarlatiniform, urticarial
or petechial, periorbital edema, uncommonly-EM, EN
Severe eruption may be associated with antibiotic Rx
ampicillin , amoxicillin.
Fever, muscle and joint pain, thrombocytopenia
causing petechiae, ecchymoses, mucosal bleeding,
exanthematous rash, generalized erythema with areas
of normal skin.
Fever, arthralgia, exanthem, rash appears 1-10 days,
fades in 1 week, unusual features- vesiculobullous,
purpuric macules, pigmentation, aphthae.
Dengue
Skin Rash and Subconjunctival Haemorrhage
Note the well-defined islands of uninvolved skin in a sea of erythema
Other Infections
Other infections
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Staphylococcal Scalded Skin Syndrome (SSSS) : Staphylococcal aureus
Scarlet fever : streptococcus pyrogenic exotoxin A.
Toxic Shock syndrome : Staphylococcal aureus or streptococcus pyogenes.
Meningococcemia : N. meningitidis
Pseudomonas, Pneumococcal, H. influenza infections.
Enteric fever
Leptospirosis
Syphilis
Rickettsial infections
Clinical picture of sepsis, DIC- Disseminated purpuric papules plaques,
infarcts, peripheral gangrene, purpura fulminans, necrotic areas with eschar
formation.
Staphylococcal scalded skin syndrome
 Also known as Ritter’s disease.
 Phage group II staphylococcus, type 55
and 71, epidermolytic toxin.
 Diffuse erythema, scaling, blisters,
Nikolsky+.
 No mucosal involvement.
Scarlet fever
 Pharyngitis,
 Forschheimer’s spots, strawberry tongue
 Lymphadenopathy,
 Scarlatiniform rash generalized within 2
days, Pastia’s lines, fades in 1 week
 Schultz-Charlton test:
Intradermal injection of human scarlet
fever immune serum; a positive
reaction consists of blanching of the rash
in the area surrounding the point of
injection.
Scarlet fever
Toxic shock syndrome
 Toxin-mediated acute life-threatening illness, precipitated by infection
with either Staphylococcus aureus or group A Streptococcus (GAS),
also called Streptococcus pyogenes.
 Characterized by high fever, rash, hypotension, multi-organ failure
(involving at least 3 or more organ systems), and desquamation,
typically of the palms and soles, 1-2 weeks after the onset of acute
illness.
 The clinical syndrome can also include severe myalgia, vomiting,
diarrhea, headache, and nonfocal neurologic abnormalities.
Toxic shock syndrome : Evolution of signs and symptoms
Meningococcal Disease and Purpura Fulminans
 Rapid onset and fulminant course
 Prodrome
 Headache, neck stiffness, nausea,
vomitting, high grade fever and rash
within 2-5 hours
Pseudomonas aeruginosa Infections
Pseudomonas Folliculitis
Pseudomonas infections can present
as folliculitis, ecthyma gangrenosum,
or with features of sepsis
Progression of soft tissue swelling
to vesicle or bulla formation is an
ominous sign.
Enteric fever and Leptospirosis
Rose spots in typhoid
Characteristic rash in leptospirosis
Congenital Syphilis
Rickettsial infections in India
 Scrub Typhus
 Spotted Fever
 Indian Tick Typhus
 Rickettsial Pox
Classical Triad of Rickettsial Pox
 Fever
 Eschar
 Rash : numerous monomorphous papules with a small central
vesicular component
Difference of Chickenpox from Rickettsial Infections
 More number of lesions
 No eschar
 Polymorphic
Common Systemic Features
 Fever
 Myalgia,arthralgia
 G I Symptoms
 Lymphadenopathy
Rickettsial Pox
In ricketssial pox, the site of tick bite can be seen, may show escharification;
the rash can mimic chickenpox. Chicken pox has to be differentiated from
rickettsial pox by the presence of polymporphous rashes at different stages
of evolution and the presence of eschar in the latter.
Drugs
Drug Eruptions (with fever and rash)
Type
Clinical Features
Drugs
Exanthemata
Generalized,
morbilliform
Anticonvulsants, ampicillin,
cephaosporins, dapsone, sulfonamides,
NSAIDS, NNRTI
Urticarial
Wheals, variable,
angioedema
Penicillins, NSAIDs, sulfonamides,
vaccines, radiocontrast media
EM major
Target lesions,
Mucosal involvement
Anticonvulsants, AKT, sulfonamides,
NSAIDs, dapsone, NNRTI
Drug Eruptions (with fever and rash)
Type
Clinical Features
Drugs
SJS/TEN
Atypical target,
bullae, epidermal
necrosis, Mucosal
involvement,
Nikolsky+
Anticonvulsants, AKT, sulfonamides,
NSAIDs, dapsone, NNRTI
DHS
Facial edema, gen
erythema,
lymphadenopathy,
internal organ
involvement
Aromatic anticonvulsants, Sulfonamides
Erythroderma
Generalized erythema Penicillins, sulfonamides, dapsone,
with scaling
anticonvulsants
Drug vs Bug : Exanthem
Clinical Feature
Drug
Bug
Incidence
Uncommon
Common
Fever
++
++++
Constitutional symptoms ++
++++
Lymphadenopathy
++
+++
Pruritus
Present
Usually absent
Mucosal involvement
+
++
Drug vs Bug : Exanthem
Clinical Feature
Drug
Bug
Evolution of rash
Variable evolution,
Characteristic evolution,
subsides slowly after drug prodrome, rash and fever,
withdrawal, 1-2 weeks
subsides faster 3-5 days
Skin biopsy
Interface dermatitis
Perivascular mononuclear
Laboratory values
Eosinophilia, abnormal
liver enzymes
Lymphocytosis
Severe Urticaria and erythema multiforme
Early Lesions of TEN
Extensive Skin Involvement in TEN
Arthritis, Fever and Rash
 Viral infections
 Acute rheumatic fever
•
Rubella
 Kawasaki disease
•
Parvovirus B-19
 Urticarial vasculitis
•
Gonococcemia
 Acute sarcoidosis
 Other infections
 Still’s disease
•
Meningococcemia
•
Lyme borreliosis
•
Familial mediterranean fever
•
Secondary syphilis
•
Hyperimmunoglobulinemia D
syndrome
 Periodic fever syndromes
Vasculitis : Palpable purpura
Erythema Chronicum Migrans
(Lyme disease) caused by
Borrelia burgdorferi
Dysaesthesia (Pain/ paraesthesia/ pruritus) without obvious
primary lesion
 Delusion of parasitosis
 Neurodermatitis
 Neuropathy or stroke
 Notalgia paresthetica
 Polycythemia vera
 Porphyria
 Impending bullous impetigo, cellulitis
 Herpes virus infections
Painful Nodules
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Eccrine spiradenoma
Neurilemmoma
Glomus tumor
Leiomyoma
Angiolipoma
Dercum’s disease (adiposis dolorosa)
Neuroma and neurofibroma (sometimes)
Dermatofibroma (sometimes)
Arthropod bite or sting
Blue rubber bleb nevus
Chondrodermatitis nodularis helicis
Cutaneous endometriosis
Erythema nodosum
Erythema Nodosum
Hypo/Depigmented Lesions
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Halo nevus
Idiopathic guttate hypomelanosis
Lichen sclerosus
Lupus erythematosus (discoid
lesions)
Molluscum contagiosum
Nevus depigmentosus
Pityriasis alba
Postinflammatory
hypopigmentation
Scars
Stucco keratosis (keratosis alba)
Tinea versicolor
Vitiligo
 Albinism
 Chediak–Higashi syndrome
 Chemicals (hydroquinone, phenol,
etc.)
 Hypomelanosis of Ito
 Incontinentia pigmenti
 Leprosy
 Nevus anemicus
 Piebaldism
 Pinta
 Tuberous sclerosis (ash-leaf
macules)
 Hypopigmented mycosis
fungoides
Hypo-/Depigmented Lesions
Hansens
Post kalaazar dermal leishmaniasis
Hypo-/Depigmented Lesions
Discoid lupus erythematosus
Vitiligo
Hypo /Depigmented Lesions
Hypopigmented mycosis fungoides.
Malar Rash
Clinical Entity
Distinguishing clinical features
Distinguishing laboratory
features
Acute cutaneous lupus
erythematosus
Photosensitivity, rash spares
nasolabial folds; clinical
evidence of active SLE
Positive ANA with confirmed SLE
serology and other laboratory
parameters
Dermatomyositis
Violaceous erythema often with
edema; involves eyelids,
periorbital and/or malar areas
but spares nasolabial folds;
often pruritic
Positive ANA, elevated muscle
enzymes (amyopathic form can
occur, however); myositisspecific autoantibodies
Allergic contact or
airborne dermatitis
History of contact exposure
Negative ANA, positive patchtest results
Rosacea
Papules and pustules
Negative ANA
Malar Rash
Clinical Entity
Distinguishing clinical features
Distinguishing laboratory
features
Seborrheic dermatitis
Greasy or scaly macules and
papules that involve the
nasolabial folds, cheeks, chin
and scalp
Negative ANA
Eczematous (atopic)
dermatitis
Papulo-vesicular lesions after
first sun exposure following
winter in northern latitudes;
might be difficult to distinguish
from ACLE and photo-induced
eruptions in early phases
Negative ANA
IgE can be elevated
Malar Rash
Clinical Entity
Distinguishing clinical features
Distinguishing laboratory
features
Polymorphous light
eruption
Papulo-vesicular lesions after
first sun exposure might be
difficult to distinguish from ACLE Negative ANA
and photo-induced eruptions in
early phases
Photo-induced, drugrelated eruptions
History of prior exposure,
confined to sun-exposed areas
Negative ANA
Exaggerated flushing
reactions (functional or
medical, carcinoid,
pheochromocytoma)
Not photosensitive
Negative ANA
Malar Rash
SLE
Rosacea
Thickened Nerves
 Mnemonic : LANDS
•
Leprosy
•
Amyloidosis
•
Neurofibromatosis
•
Diabetes
•
Sarcoidosis
Bubo
 Cat-scratch disease
 Chancroid
 Lymphogranuloma venereum
 Tularemia
 Bubonic plague
Genital Ulcer Disease
Infectious
Non-infectious
 Herpes simplex virus (HSV)
 Behcet’s disease
 Syphilis
 Squamous cell carcinoma
 Chancroid
 Trauma
 Lymphogranuloma venereum
(LGV)
 Drug-induced
 Donavanosis
 Granuloma inguinale
 HIV
Herpes progenitalis
Bechet’s Disease
Annular Lesions
Annular macules or minimally elevated plaques
 Cutis marmorata
 Erythema multiforme
 Erythema ab igne
 Erythema chronicum migrans
 Erythema marginatum
 Livedo reticularis
 Purpura annularis telangiectoides
 Targetoid hemosiderotic hemangioma
Annular papules or plaques with no scale
 Basal cell carcinoma
 Granuloma annulare
 Sebaceous hyperplasia
 Desmoplastic trichoepithelioma
 Sarcoidosis
Granuloma annulare
Annular plaques with some scale or crust
 Basal cell carcinoma
 Eczema, especially nummular
 Prurigo
 Annular lichen planus
 Lupus erythematosus (especially Ro-positive SCLE)
 Pityriasis rosea
 Psoriasis
 Reiter’s disease (circinate balanitis)
 Seborrheic dermatitis
 Tinea corporis
 CD30+ Anaplastic Large Cell T Cell Lymphoma
 Cutaneous small vessel vasculitis
Annular plaques with some scale or crust
Secondary Syphilis
Tinea Corporis
Prurigo Nodularis
Annular plaques – infiltrative with or without scaling
 Lupus vulgaris
 Chromomycosis
 Hansen’s disease
 Elastosis perforans serpiginosa (EPS)
 Erythema annulare centrifugum ( EAC)
 Erythema gyratum repens (EGR)
 Erythrokeratodermia variabilis
 Ichthyosis linearis circumflexa
 Mycosis fungoides
 Porokeratosis
 Necrolytic migratory erythema
Annular plaques
Icthyosis linearis circumflexa
Lupus vulgaris
Erythema annulare centrifugum
Annular plaques
CD30+ Anaplastic Large Cell T Cell Lymphoma: Annular plaque
with scaling and erythema along with subcutaneous nodules
Annular vesicles or pustules
 Linear IgA bullous dermatosis
 Pemphigus
 Subcorneal pustular dermatosis
 Fixed drug eruption
Subcorneal pustular dermatoses
MCQ’s
Q.1)
A.
B.
C.
D.
All of the following may present as annular vesicles, except:
Linear IgA bullous dermatosis
Pemphigus
Subcorneal pustular dermatosis
Hansen’s disease
Q.2)
A.
B.
C.
D.
All of the following may cause genital ulcer, except :
Herpes simplex
Squamous cell carcinoma
Cutis marmorata
Behcet disease
MCQ’s
Q.3)
A.
B.
C.
D.
All of the following may present with thickened nerves, except :
Amyloidosis
Cat scratch disease
Neurofibromatosis
Sarcoidosis
Q.4)
A.
B.
C.
D.
Malar rash with negative ANA is found in :
Polymorphous light-induced eruption
Acute cutaneous lupus erythematosus
Systemic lupus erythematosus
Dermatomyositis
MCQ’s
Q.5) A 8 year old child, came with chief complaints of hypopigmented
lesion over forearm since last 8 months,
The diagnosis of Leprosy was made based on the presence of the
following except :
A. Hypoaesthesia
B. Hypohydrosis
C. Hypotrichosis
D. Loss of triple response of lewis
Photo Quiz
Q. Describe the lesion and give differential diagnosis.
Photo Quiz
Q. Give a differential diagnosis.
Thank You!