Skin inflammation + infections

Question 1

What are the 5 cardinal signs of acute inflammation?

Answer 1

Redness, heat, swelling (accumulation of exudate), pain, loss of function (Virchow)

Question 2

What causes redness and heat in inflammation?

Answer 2

Vasodilation and increased blood flow

Question 3

What causes swelling in inflammation?

Answer 3

Fluid exudate accumulation

Question 4

Which cell is the primary antigen-presenting cell in the epidermis?

Answer 4

Langerhans cells are antigen-presenting dendritic cells (transport antigens to lymph nodes/ PRESENT ANTIGENS TO CD4+ T helper cells)

Question 5

What cell type mediates IgE-dependent allergic reactions (e.g., urticaria)?

Answer 5

Mast cells (degranulate histamine, leukotrienes)

Question 6

Which cell type is elevated in granulomatous inflammation (e.g., TB)?

Answer 6

Macrophages (form epithelioid/Langhans giant cells)

Question 7

What mediates mast cell/IgE inflammation (e.g., urticaria)?

Answer 7

Allergens (dust mites, nuts) → IgE → mast cell degranulation → histamine → vasodilation, pruritus, bronchospasm

Question 8

What is the mechanism of antibody-mediated inflammation in pemphigus vulgaris?

Answer 8

IgG targets desmoglein-3 → histology shows acantholysis (suprabasal splitting; loss of cohesion between epidermal keratinocytes)

treated with either steroid tablets like mycophenolate or azathioprine BUT BEST FOR IT IS rituximab (targets CD20 on B cells!

Question 9

What causes immune complex-mediated vasculitis?

Answer 9

Immune-complex (IC) deposition (e.g., anti-DNA in SLE) → complement activation → neutrophil recruitment → vessel necrosis

Question 10

What is the hallmark of delayed hypersensitivity (e.g., contact dermatitis)?

Answer 10

Th1 response (IFN-γ, IL-2) → peak inflammation at 48–72 hours (e.g., nickel allergy)

Question 11

What are classic contact allergens?

Answer 11

Nickel (jewelry), rubber (clothing), parabens (cosmetics)

Question 12

How is pemphigus vulgaris treated?

Answer 12

Steroids + immunosuppressants (azathioprine, rituximab)

Question 13

What is omalizumab used for?

Answer 13

Anti-IgE monoclonal antibody for resistant urticaria/asthma

Question 14

What cytokines drive granuloma formation (e.g., sarcoidosis)?

Answer 14

Th1 cytokines (IFN-γ, TNF, IL-2)

Question 15

What are examples of cutaneous autoimmune diseases?

Answer 15

Alopecia areata (hair follicles), vitiligo (melanocytes)

Question 16

What is a new treatment for alopecia areata/vitiligo?

Answer 16

JAK inhibitors (e.g., ruxolitinib)

Question 17

What are the effects of histamine?

Answer 17

Pruritus, vasodilation (H1), bronchospasm, gastric acid secretion (H2)

Question 18

What is Der p1?

Answer 18

Der p 1 is a major allergen produced by the house dust mite Dermatophagoides pteronyssinus

Type of Molecule: Der p 1 is a cysteine protease enzyme.

Function in Mites: It helps the mite digest its food (typically skin flakes) by breaking down proteins.

Dust mite allergen → disrupts tight junctions → crosses mucosa

Question 19

What organism causes impetigo and what is its classic appearance?

Answer 19

Staph. aureus!!! or Strep. pyogenes; honey-colored crusts on face

Question 20

How does cellulitis differ from erysipelas?

Answer 20

Cellulitis: deeper (dermis/subcutis), indistinct borders.

Erysipelas: superficial (dermis only), sharp borders (often Strep. pyogenes)

Question 21

What causes scalded skin syndrome?

Answer 21

Staph. aureus exotoxins → desmosome destruction → widespread blistering

Question 22

First-line treatment for necrotizing fasciitis?

Answer 22

Emergent surgical debridement + broad-spectrum IV antibiotics (e.g., piperacillin-tazobactam + clindamycin)

Question 23

Which HPV types cause plantar warts?

Answer 23

HPV 1, 2, 4 (verruca).

Flat warts: HPV 3, 10, 28.

Question 24

What triggers shingles (herpes zoster)?

Answer 24

Reactivation of VZV in dorsal root ganglia → unilateral dermatomal rash

Question 25

How is molluscum contagiosum spread?

Answer 25

Direct contact/fomites; resolves spontaneously (or cryotherapy if severe)

Question 26

What causes tinea versicolor?

Answer 26

Malassezia overgrowth → hypopigmented/scaly patches (ketoconazole shampoo)

Question 27

Tinea capitis requires what treatment?

Answer 27

Oral antifungals (e.g., griseofulvin or terbinafine) — topical agents fail (hair follicle involvement).

Question 28

Classic presentation of Candida intertrigo?

Answer 28

Red, macerated plaques in skin folds (obesity/diabetes risk factors)

Question 29

Scabies vs. crusted scabies?

Answer 29

Scabies: 10–15 mites, allergic reaction. Crusted scabies: thousands of mites (immunocompromised); treat with permethrin/ivermectin

Question 30

What is the hallmark rash of Lyme disease?

Answer 30

Erythema migrans (expanding red oval, non-painful, ~1 week post-tick bite) caused by Lyme disease by Borrelia genus e.g. Borrelia burgdorferi

Question 31

Acne vulgaris causative pathogen + pathogenesis?

Answer 31

Propionibacterium acnes + sebum → follicular clogging → inflammation (treat with benzoyl peroxide/retinoids)

Question 32

Hot tub folliculitis culprit?

Answer 32

Pseudomonas aeruginosa (treated with ciprofloxacin if severe)

Question 33

Leprosy skin findings?

Answer 33

Pale/pink anesthetic patches (M. leprae; treat with rifampicin/dapsone/clofazimine)

Question 34

Toxic epidermal necrolysis (TEN) vs. staphylococcal scalded skin syndrome (SSSS)?

Answer 34

TEN: Drug-induced, full-thickness necrosis. SSSS: Staph. aureus toxins, superficial split (granulosum)

Question 35

Cutaneous TB (lupus vulgaris) appearance?

Answer 35

Painful facial nodules/ulcers (anti-TB drugs: rifampicin/isoniazid)

Question 36

what is the antigen and antibody for 1) Systemic Lupus Erythematosus (SLE) 2) polyartiritis nodosa

Answer 36

1) Systemic Lupus Erythematosus (SLE)= antigen is DNS; antibody is Anti-DNA 2) polyartiritis nodosa= antigen is Hepatitis B surface antigen (HBsAg); antibody is Anti-HBs Ab

Question 37

Barber's itch (looks like pimples with white top) and impetigo (honey crusted cornflakes round mouth) are usually caused by same causative pathogen, which is?

Answer 37

Both Barber's itch/rash and impetigo are usually caused by staphylococcus aureus