CM- Approach to Scaling Disorders

Question 1

Define the terms guttate, nummular, pityriasis.

Answer 1

Guttate - drop shaped
Nummular- shaped like a coin
Pityriasis- bran-like flakes of scale

Question 2

What is a scale?

Answer 2

piece of stratum corneum. Usually they are so small that they go undetected, but in disorders, abnormal stratum corneum accumulates and forms visible flakes

Question 3

What are the 3 main functions of skin?

Answer 3

1. mechanical protection
2. prevent water loss
3. immunological defense

Question 4

Describe the normal development of the skin [keratinization].
What 3 disruptions to keratinization can lead to scaling?

Answer 4

Pool of stem cells in basal cells mature as they rise to the stratum corneum. The end result takes 2 weeks and is an anucleate, non-viable corneocyte that populates the most superficial layer of the epidermis [80% protein, 20% lipids]
Shedding takes 2 weeks after degradation of the lipids and cell adhesion proteins.

Scaling can be caused by:

1. increased proliferation of basal keratinocytes
2. abnormal maturation
3. increased retention of corneocytes

Question 5

What is the effect of inflammation on scaling?

Answer 5

Inflammatory conditions –> released cytokines–> increased proliferation of basal keratinocytes

This results in excess, incompletely matured keratinocytes–> nucleated stratum corneum [parakeratosis]

Question 6

What is parakeratosis?

What is the cause?

Answer 6

It is nucleated stratum corneum cells. It is caused by increased proliferation of basal keratinocytes leading to excess of incompletely matured cells

Question 7

What is the pathogenesis of psoriasis?

Answer 7

1. genetic predisposition [HLA-B27]

2. immune triggers that inappropriately activate the immune response

Question 8

What is the histology of psoriasis?

Answer 8

1. inflammatory cells in the epidermis and dermis
2. accumulation of neutrophils [munro’s microabsesses]
3. increased mitoses in keratinocytes, fibroblasts, endothelial cells
4. thickened epidermis [acanthosis]
5. retention of nuclei in the horny layer with absence of granular layer
6. parakeratotic hyperkeratosis [nucleated stratum corneum]

Question 9

What are the 5 clinical patterns of psoriasis?

Answer 9

1. plaque type [classic and most common]
2. guttate type [drop-shaped]
3. Inverse [ axilla, gluteal cleft] macerated/less obvious
4. erythrodermic -diffuse over whole body
5. pustular - localized to palms or soles

Question 10

What 3 diagnostic clues point to psoriasis?

Answer 10

1. Koebner phenomenon - primary lesion induced by trauma to the skin
2. Nail involvement - pits, oil-drop changes, onycholysis [detachment of nail from nail bed]
3. arthritis [asymmetric]

Question 11

What areas of the body tend to be affected by psoriasis?

Answer 11

1. scalp
2. nails
3. sacral area
4. extensor surfaces
5. shins & knees
6. elbows
7. palms and soles

Question 12

What is the pathogenesis of secondary stage syphilis?

Answer 12

Cutaneous dissemination of treponema pallidum

Question 13

Describe the histology of secondary syphilis.

Answer 13

1. epidermal hyperkeratosis [thickening of stratum corneum]
2. perivascular monocytes, lymphocytes and plasma cells in the dermal layer
3. dilation and proliferation of capillaries and lymphatics in the dermis
4. silver stain shows spirochetes

Question 14

What is the “classic” presentation of secondary syphilis?

Answer 14

1. red/brown macules or papules on trunk AND extremities [freq. palms and soles]
2. diffuse hair loss/ lateral 1/3 of eyebrow loss
3. “great imitator” - can mimic:
   - ptyriasis rosea
   - guttate psoriasis
   - lichen planus
   - sarcoidosis
4. condyloma lata- vesicles/pustules or mucus patches

Question 15

What is the histology of seborrheic dermatitis?

Answer 15

1. parakeratosis focally around the edges of follicular ostia [opening where hair emerges from the follicle]
2. spongiosis [intracellular edema] with neutrophilic infiltrate

Question 16

What are common locations for seborrheic dermatitis?

Answer 16

1. scalp
2. eyebrows
3. eyelids
4. nasolabial folds
5. ears
6. sternum
7. axillae
8. submammory folds
9. umbilicus
10. groin
11. gluteal creases

Question 17

What are the 5 types of seborrheic dermatitis?

Answer 17

1. Classic - “greasy” yellowish scales on face, dandruff on scalp
2. infantile - prominent scalp involvement
3. “sebopsoriasis”- mixed psoriasis and seborrheic dermatitis
4. Erythroderma
5. immunosuppressed have it florid and treatment resistant

Question 18

What is the histology of pityriasis rosea?

Answer 18

1. parakeratosis that is patchy or diffuse and contains serum
2. spongiotic dermatitis with perivascular lymphocytic infiltrate

Question 19

A patient presents with a herald patch [open ring] on the trunk with crops of smaller round to oval salmon-color patches following lines of cleavage [“christmas tree pattern”]. There are peripherally attached thin scales.
What does this pattern describe?

Answer 19

Pityriasis rosea

Question 20

Describe the histology of pityriasis lichenoides.

Answer 20

1. parakeratosis and spongiosis in the epidermis
2. keratinocyte necrosis
3. erythrocytes in the epidermis
4. wedge-shaped inflammatory cell infiltrate in the dermis

Question 21

Describe the acute and chronic presentation of pityriasis lichenoides.

Answer 21

Acute - bright red, erythematous papules that can erode/ulcerate

Chronic:

1. red-brown lesion
2. micaceous [aluminum silicate chalky residue] scale
3. post inflammatory hyperpigmentation

Question 22

You are looking at a slide and see:

1. irregular acanthosis with hypergranulosis
2. hyperkeratosis
3. Civatte/colloid bodies
4. band like infiltrate at dermal-epidermal junction
5. pigment incontinence - loss of melanin from basal cells with accumulation in upper dermis melanophages

What is the likely diagnosis?

Answer 22

Lichen planus

Question 23

A patient presents with flat-topped, polygonal violaceous papules that coalesce into plaques. The surface has a fine scale with a network of white lines [Wickham striae] going through.
The lesions are primarily on the wrist, pretibial area and mucus membranes including oral lesions - buccal mucosa with white papules in reticular pattern. The patients nails are rough with longitudinal ridging, thinning and pterygium formation.

What does the patient have?

Answer 23

Lichen planus

Question 24

What is the histology of lichen simplex chronicus?

Answer 24

1. Hyperplasia of the epidermis
2. hyperkeratosis
3. hypergranulosis
4. acanthosis
5. elongated and irregular rete ridges
6. spongiosis

Question 25

A patient present with a thickened and hyperpigmented plaque. Skin lines are visible and the area is sharply demarcated. There is some excoriations and pruritus is a prominent feature. What is the likely diagnosis?

Answer 25

Lichen simplex chronicus

Question 26

Most ichthyoses have non-specific histology but share what 2 features? Which 2 types of ichthyoses have unique features and what are they?

Answer 26

1. compact hyperkeratosis 2. normal or thickened granular layer Ichthyosis vulgaris - decreased or absent granular layer Epidermolytic hyperkeratosis- 1. hypergranulosis with giant keratohyalin granules 2. keratinocyte lysis resulting in subcutaneous vacuolization and vesicles

Question 27

You look at histology of a skin lesion and see: 1. hypergranulosis with giant keratohyalin granules 2. keratinocyte lysis with subcutaneous vacuolization and vesicles What is the diagnosis?

Answer 27

Epidermolytic hyperkeratosis

Question 28

What is the inheritance pattern of ichthyosis vulgaris? What is the mutation in? What is the presentation?

Answer 28

It is an autosomal dominant mutation in filaggrin. Patient will present with non-inflamed scaling that can be fine or thick. Patients can also present with: 1. atopic dermatitis 2. keratosis pilaris 3. hyperlinearity 4. thickening of palms and soles

Question 29

What is the mutation in X-linked ichtyosis? What area of the body is most affected? What areas are spared?

Answer 29

It is a mutation in steroid sulfatase. Neck is almost always involved Palms, soles, and face are spared

Question 30

What is the inheritance pattern and mutation in lamellar ichtyosis? How do newborns present? How do adults present?

Answer 30

autosomal recessive mutation in transglutaminase 1, ABCA12. Newborns have colloidion membrane Adults have thick, plate-like scale

Question 31

What is the inheritance pattern and mutation in epidermolytic hyperkeratosis?

Answer 31

Autosomal recessive mutation in Keratin 1 or 10 Newborns present with blisters and erosions Later in life, erosions are replaced by hyperkeratosis

Question 32

What do you do if there is a possibility of fungal origin for a scaling disorder?

Answer 32

KOH scraping for microscopic analysis

Question 33

How does scaling of papulosquamous lesions present?

Answer 33

predominant papules/plaques with prominent scaling

Question 34

How does scaling of erythrodermic lesions present?

Answer 34

widespread erythema with fine/subtle scaling

Question 35

Differentiate acute, subacute and chronic dermatitis.

Answer 35

Acute -very inflamed/exudative [oozing, weeping, blisters] Subacute - intermediate Chronic- dry, scaly, lichenification