L43 Drugs used in Skin Disorders →↑↓

Question 1

Drugs for common skin disorders

Answer 1

→ Antimicrobial agents

→ Antihistamines
→Histamine receptors in human skin mast cells (both H1 and H2)
→First and second generation H1 blockers H2 blockers:cimetidine, ranitidine & famotidine
→ Glucocorticoids
→ Cytotoxic & immunosuppressives
Antimetabolites: methotrexate, azathioprine and fluorouracil (5-FU)
Alkylating agents: cyclophosphamide
→ Calcineurin inhibitors: cyclosporine, tacrolimus & pimecrolimus
→ Retinoids

Question 2

→ Retinoids

Answer 2

VitaminA-like
→ Bind to nuclear retinoid receptors
→Retinoid functions: inhibit cell proliferation (growth &
development), immune defense & vision

Correct abnormal follicle keratinization, reduce bacterial
counts and inflammation
→ First line for acne treatment

Retinoic acid:
tretinoin
MoA
→Increase cell turnover → skin peeling
S/E
→May be irritating (avoid contact with eye and mucous membrane)
(photolabile and inactivated by
benzoyl peroxide)

Adapalene: similar to tretinoid but stable in sunlight and to benzoyl peroxide

Question 3

Treatment Pruritus

Answer 3

Emollients (cream, ointment & lotion)
Coolants (menthol risk of G^PD deficiency, camphor, calamine)
Miscellaneous OTC products
Antihistamines(topical and systemic)
Steroids (topical)
Immunosuppressants and anti- inflammatory
(normally not required)

Question 4

Treament of Acne or acne vulgaris

Answer 4

Benzoyl peroxide and azelaic acid

Benzoyl peroxide
→ penetrate and converted to benzoic acid
→ Both have antimicrobial activity against P acnes
→ Skin drying and peeling effect
→ Benzoyl peroxide combination with antibiotics (e.g. clindamycin and erythromycin)

Question 5

Treament of Eczema (濕疹) /dermatitis (皮膚炎)

Answer 5

Moisturizer to relief dryness (avoid soaps and detergents)
→ Itch relief with antihistamines (topical or oral)
→ Corticosteroids: start with weak-mild groups and higher potency may be required
→ Immunosuppresants in sever and persistent cases
→ Some similarity to treatment of urticaria (see below)

Question 6

Treatment of Urticaria

Answer 6

Acute urticaria
Chronic urticaria (more than 6 weeks)
→ Identify and remove trigger if possible
→ Cooling medications
→ Antihistamines
→ Glucocorticoids
→ Combination with glucocorticoids

Question 7

Treatment of Psoriasis

Answer 7

Immune-mediated chronic skin problem
→ Skin cells to grow too quickly → thick, white, silvery or red patches of skin

Skin cream and moisturizers
→ Topical corticosteroids or retinoids (combination)
→ Immunosuppressants for severe cases
→ Systemic methotrexate or cyclosporine
→ Antibodies against inflammatory factors
(Secukinumab, ixekizumab, and brodalumab are three anti-IL-17 medications used for treating psoriasis)

Question 8

Treatment of Hyperkeratotic disorders

Answer 8

Warts and Corn

Treatment
Salicylic acid
→Soften stratum corneum

α-Hydroxy acids
→Similar effect as salicylic acid

Urea
→Softening and moisturizing effect
→ Increase solubilization and removal of
cells from stratum corneum