Papulosquamous disease: psoriasis, dermatophyte infections, lichen planus, pityriasis rosea

Question 1

Define psoriasis? RFs?

Answer 1

A chronic autoimmune disease characterised by well-demarcated, erythematous, scaly plaques.

Skin trauma (Koebner phenomenon)
Infection: Streptococcus, HIV
Drugs: BB, Anti-malarials, Lithium, Indomethacin/NSAIDs (BALI)
Withdrawal of steroids
Stress
Alcohol + smoking
Cold/dry weather
FHx
Obesity
European descent

Question 2

Presentation of psoriasis?

Answer 2

itchy

well-demarcated circular-to-oval bright red/pink plaques WITH overlying white or or silvery scale.

scales are loose and easily removed by scratching.

distributed symmetrically over extensor body surfaces and the scalp.
e.g. palms, soles, nails, elbows, knees, lower back, perineum, anterior tibial surface.

Nail changes are seen:
- nailbed pitting (depression)
- Onycholysis (separation)
- Subungual hyperkeratosis (thickening)

Question 3

Triggers of psoriasis?

Answer 3

Strep infection
Drugs
UV light exposure
Trauma
Hormonal changes
HIV infection and AIDS
Smoking
Alcohol
Psychological stress

Question 4

Management of psoriasis?

Answer 4

Pt education
It is not an infectious disease.

Lifestyle:
- smoking cessation
- reduce alcohol
- weight loss
- manage stress and anxiety​

Topical:
- cream/lotions/gel
- Vitamin D Analogues – calcipotriol​ and tacalictol

Scalp psoriasis
– salicyclic acid with coal tar/sulphur​

Mild or moderate topical steroid for facial, flexural and genital.

Question 5

Define dermatophyte infections? Found where? Transmission?

Answer 5

Group of fungi that infect non-viable keratinised skin structures​.

Epidermal dermatophytosis – invades stratus corneum​

Trichomycosis – affects hair and hair follicles​

Onychomycosis – affects nail

Worse in humid climates or warm moist body areas.
Found in soil.
Transmission human or animals.

Question 6

Diagnosis and tx of dermatophyte infections?

Answer 6

KOH (potassium hydroxide) microscopy

Tx:
- clotrimazole, miconazole, terbinafine

Question 7

Define lichen planus?

Answer 7

a chronic T-cell mediated inflammatory disorder.

is a rash that can affect different parts of your body, including the inside of your mouth.

Question 8

Presentation of lichen planus?

Answer 8

Four P’s
- pruritic
- purple
- polygonal papules

Coalesce into plaques

Found in wrists, ankles, shins, penis, mucous membranes.

Question 9

Tx for lichen planus?

Answer 9

Strong topical steroid
UV therapy
Sedating antihistamine (chlorphenoxamine)
Monitor mucous membrane cases for SCC.

Question 10

Define pityriasis rosea?

Answer 10

A self-limiting rash that resolves after 10 weeks.

Unknown causes, maybe human herpes virus.

Question 11

Presentation of pityriasis rosea? Tx?

Answer 11

Occurs after a viral infection e.g. URTI
may have viral symptoms -headache, fatigue, loss of appetite

herald patch
red-pink oval/discoid plaque with a peripheral colarette of scale

found on trunk or upper arm/thigh
may be misdiagnosed as ringworm

Tx:
- self-limiting
- antihistamines, emollients, steroids (if intense itching)