Dermatological grouping differential diagnosis

Question 1

Erythematous maculopapular rashes

Answer 1

Infection:MMR erythema infectosium, drug induced, DRESS, secondary syphilis
Autoimmune/inflammatory: lupus erythematosus, dermatomyositis, sarcoidosis
Other: EM, pityriasis rosea

Question 2

Vesiculobullous

Answer 2

Infectious: HSV, VZV, HFMD
AI: pemphigus vulgaris, bullous pemphigoid, dermatitis herpitiformis
Other: burns, porphyria cutanea tarda, epidermolysis bullosa

Question 3

Scaling and plaques

Answer 3

Inflammatory: psoriasis, eczema/atopic dermatitis, seborrheic dermatitis
Infectious: tinea corporis, secondary syphilis, pityriasis versicolor
Other: ichythosis, cutaneous T cell lymphoma, lichen simplex chronic

Question 4

Nodules/tumours

Answer 4

Infectious: mycobacterial (TB, leprosy), deep fungal (sporotrichosis, cryptococcosis)
Neoplastic: BCC, SCC, melanoma
Inflammatory/other: sarcoid, rheumatoid nodules, erythema nodosum

Question 5

Urticarial and angioedema

Answer 5

Drug or food allergies
Serum sickness
AI urticaria
post-strep urticaria
Hereditary angioedema
Idiopathic urticaria

Question 6

Hypopigmented or depigmented lesions

Answer 6

Disorders: vitiligo, albinism, post-inflammatory hypopigmentation
Infectious: tinea versicolor, leprosy, pityriasis alba, guttate hypomalanosis

Question 7

Purpuric/hemorrhagic lesions

Answer 7

HSP, PNA
ITP, DIC
Trauma

Question 8

Ulcers

Answer 8

Infectious: pyoderma gangrenous, leishmaniasis, mycobacterial ulcers
Vascular: venous states, arterial, diabetic foot
Pressure sores

Question 9

Pruritic

Answer 9

Dermatitis: atopic, contact
Infestations: scabies, lice
Systemic: CKD, liver disease
Other: prurigo nodular, drug reactions