L12 Dermatological 2025_formatted_text

THE UNIVERSITY OF WESTERN AUSTRALIA

DENT 3005: Introduction to Pharmacology¹

Dermatological drugs

Dr Thuy Linh Truong thuy.truong@uwa.edu.au

Learning Outcomes²

Learning objectives

1. Understand the classes and mechanisms of major classes of dermatological drugs
2. Recognise common dermatological conditions relevant to dentistry
3. Recognise oral and dental side effects of dermatological drugs
4. Understand drugs interactions with dental medications
5. Applied knowledge to clinical scenarios

Skin Anatomy³

An image depicting the layers of the skin and associated structures.

• Epidermis
  • Stratum corneum
  • Stratum lucidum
  • Stratum granulosum
  • Stratum spinosum
  • Stratum basale
• Dermis
• Subdermis

Associated Structures:

• Hair follicles
• Erector pili muscle
• Sebaceous glands
• Arteriole
• Capillaries
• Eccrine glands
• Sensory nerve
• Fat, collagen, fibroblasts

Drugs for Eczema⁴

• Aka dermatitis
• Characterized by skin inflammation & itching
• Most common: atopic eczema
• MOA: anti-inflammatory, immunosuppressive & anti-mitotic activity against cutaneous fibroblasts
• Adverse reactions: depends on potency, length of tx, age, site & extent of disease

Drug therapy	Generic name
Moisturizers	☺
Corticosteroids	Betamethasone
	Clobetasol
	Clobetasone
	Desonide
	Hydrocortisone
	Methylprednisolone
	Mometasone
	Traimcinolone
Tars	Coal tar
	Ichthammol
	Wood tars
Calcinuerin inH	Pimecrolimus

Topical Corticosteroid Preparations (Therapeutic Guidelines)⁵

Drug (brand examples)	Strength	Preparations
Mild corticosteroids [NB1][NB2]
desonide (Desowen)	0.05%	lotion
hydrocortisone (DermAid)	0.5%, 1%	cream, ointment, topic liquid, spray
hydrocortisone acetate (Cortic DS, HydroCortic, Hysoderm, Sigmacort)
Moderate corticosteroids [NB1][NB2]
betamethasone valerate (Antroquoril, Betnovate 1/5, Celestone-M, Cortival 1/5)	0.02%	cream
betamethasone valerate (Betnovate 1/2, Cortival 1/2)	0.05%	cream, ointment
clobetasone butyrate (Eumovate, Kloxema)	0.05%	cream
triamcinolone acetonide (Aristocort, Tricortone)	0.02%	cream, ointment
Potent corticosteroids [NB1][NB2]
betamethasone dipropionate (Diprosone, Eleuphrat)	0.05%	cream, ointment, lotion
betamethasone valerate (Betnovate)	0.1%	cream, ointment
methylprednisolone aceponate (Advantan)	0.1%	cream, ointment, fatty ointment, lotion
mometasone furoate (Elocon, Momasone, Novasone, Zatamil)	0.1%	cream, ointment, hydrogel, lotion
Very potent corticosteroids [NB1][NB2]
betamethasone dipropionate (Diprosone OV)	0.05% in optimised vehicle	ointment in optimised vehicle
clobetasol propionate (Clobex)	0.05%	cream, ointment, lotion, shampoo [NB3]

OV = optimised vehicle

NB1: Potency classification for each drug is based on the results of vasoconstrictor studies. Potency classifications based on vasoconstrictor effect typically correlate with therapeutic potency; however, many other factors determine therapeutic potency in a patient (eg area of application, frequency and duration of treatment).

NB2: Formulation of a drug can affect potency; a topical drug prepared as a cream is less potent than the same drug prepared as an ointment.

NB3: A commercial product is available for clobetasol propionate as a shampoo. Clobetasol propionate as a cream, ointment or lotion is not registered for use in Australia, but is available through the Special Access Scheme (for certain indications) or from compounding pharmacies; only use these under specialist supervision.

Eczema

Drugs for Psoriasis⁶

• Chronic inflammatory disease: plaque psoriasis is most common form
  • Affecting elbows, knees, buttocks, scalp
• Drug therapy rationale: induce remission, reduce severity & extent, relieve sx
• If possible, minimise & eliminate triggers
  • Stress, trauma, smoking, alcohol, infections, drugs induced
• Topical tx adjunct to photo-therapy
• Systemic tx guided by dermatologists due to serious side effects

Drug therapy	Generic name
Topical treatment	Moisturisers
	Corticosteroids
	Calcipotriol
	Salicylic acid
	Coal tars
	Dithranol
Systemic treatment	MTX
	Cyclosporin
	Acitretin
	Injectable cytokine modulators
	IL inH
	TNF-alpha antagonists
Other drugs	Methoxsalen

Drugs for Acne⁷

• Acne vulagris: common skin condition
• Rationale of tx: improve complexion, px scarring, limit disease duration, reduce psychological stress
• Endocrine evaluation
• Topical tx choice
  • Retinoids, benzoyl peroxide & azelaic acid,
  • Antibacterials
• Oral tx choice
  • Antibacterials
  • Hormonal tx
  • Isotretinoin

Drug therapy	Generic name
Retinoids (top)	Adapalene
	Isotretinoin
	Tazarotene
	Tretinoin
Retinoids (oral)	Acitretin
	Isotretinoin
Other	Azelaic acid
	Benzoyl peroxide

Drug therapy	Generic name
Antibacterial (top)	Clindamycin
	Erythromycin
	Metronidazole
	Mupyrocin
	Silver sulfadiazine
	Sodium fusidate
Antibacterial (oral)	Doxycycline 1${}^{\text{st}}$ line
	Erythromycin

Factors Contributing to Acne⁸

• Excess oils
  • The oily substance that protects your skin can contribute to acne when too much is produced.
• Slower skin cell turnover
  • Dead skin cells that normally just fall off can get stuck in skin oils instead and clog your pores.
• Bacterial growth
  • A specific bacteria that is normally harmless begins to multiply if it gets trapped in a clogged pore.
• Inflammation
  • Multiplying bacteria trigger inflammation that results in red, swollen, painful, and pus-filled pimples.

Acne Treatment Guidelines⁹

	Mild	Moderate	Moderate to severe	Severe
	Comedonal	Papular/pustular
First line therapy	Topical retinoid	Topical retinoid + BPO or BPO/topical AB	BPO/topical AB or Topical retinoid + BPO	Topical AB + BPO + topical retinoid or Oral AB + BPO + topical retinoid
Alternatives	Salicylic acid			Oral isotretinoin
Alternatives for female patients			Hormonal therapy $\pm$ BPO/topical AB or Topical retinoid	Hormonal therapy $\pm$ BPO/topical AB or Topical retinoid
Maintenance therapy	Topical retinoid $\pm$ BPO or BPO/topical AB		Topical retinoid $\pm$ BPO or BPO/topical AB	Topical retinoid $\pm$ BPO or BPO/topical AB

Pharmacological Management of Acne – Key Points¹⁰

• Benzoyl Peroxide: Kills P. acnes, reduces inflammation, unclogs pores; use with antibiotics to reduce resistance
• Topical Retinoids (Tretinoin, Adapalene): Increase cell turnover, prevent comedones; Adapalene = fewer side effects
• COCs + Spironolactone: Reduce androgen-driven sebum production; ideal for hormonal acne
• Oral Antibiotics (Doxycycline, Erythromycin): Antibacterial + anti-inflammatory; avoid long-term monotherapy
• Isotretinoin: Reduces sebum, bacteria, and inflammation; reserved for severe/refractory acne

Important Interactions & Considerations

• Use benzoyl peroxide (AM) + retinoids (PM) to avoid inactivation
• Avoid vitamin A supplements and tetracyclines during isotretinoin therapy
• Avoid same-class oral + topical antibiotics to prevent resistance

Drugs for Skin Infections¹¹

• Tinea: superficial fungal infection
  • Azoles & other antifungal
  • [Azoles]: lots of drug interactions
• Antibacterials
  • Indication: acne vulgaris, rosacea, impetigo, px infection in burns staph infection
• Antivirals
  • Indication: mild herpes simplex

Drug class	Generic name
Azoles	Bifonazole
	Clotrimazole
	Econazole
	Ketoconazole
	Miconazole
Other antifungals	Amorolfine
	Ciclopirox
	Nyastatin
	Terbinafine
	Tonaftate

Indication	Generic name
Herpes labialis	Acyclovir
	Penciclovir
Cutaneous herpes simplex	Idoxuridine & lignocaine

Scabicides & Pediculicides¹²

• Scabies: permethrin $1^{st}$ line
• Head lice: pediculosis (infestation by louse)
  • Drug & non-drug tx available

Scabicides & pediculicides
Head lice	Scabies
Benzyl alcohol	Benzyl benzoate
Dimeticone	Crotamiton
Isopropyl myristate	Permethrin
Maldison	Ivermectin
Permethrin

Drugs for Warts

• Caused by HPV
• Classified according to location & morphology
  • Cutaneous: flat planter & palmar warts
  • Anogenital: involves vulva, vagina, cervix, penis, scrotum, urethra & rectum
  • Extracutaneous: oral & laryngeal lesions

Drugs for wart
Generic name	Brand name
Glutaraldehyde	Diswart
Imiquimod	Aldara
Podophyllotoxin	Wartec
Pophyllum resin	Extemporaneous preps
Salicylic acid

Key Dermatological Drugs: Detailed Profiles¹³

Imiquimod

• MOA: Stimulates immune response via interferon and cytokines
• Indications: Genital/perianal warts, superficial BCC (non-surgical), facial/scalp actinic keratoses
• ADR: Local skin reactions (e.g. redness, burning, erosion, pigment changes)
• Brands: Aldara, Aldiq

Podophyllotoxin

• MOA: binds to tubulin, arresting mitosis in metaphase and leading to epithelial cell death
• Indication: anogenital warts
• Brand name: condyline paint

Drugs for Actinic Keratosis¹⁴

• Is a precursor for SCC
• Typically affecting elderly
• Rough, scaly patch on skin cause by prolonged sun exposure

Drugs for actinic keratosis
Generic name	Brand Name
Diclofenac	Solaraze
5-fluorouracil	Efudix
Imiquimod	Aldara
Ingenol mebutate	Picato
Methyl aminolevulinate	Metvix

Drugs for Alopecia

• Androgenic alopecia
• May marginally stimulate hair growth
  • Benefit stops when tx stops 🙁
  • 3-4 mo to notice effect

Drugs for alopecia
Generic name	Brand Name
Finasteride	Finapen, Propecia
Minoxidil	Regaine

5-Flurouracil (skin)¹⁵

• MOA: Antimetabolite that blocks DNA/RNA synthesis by inhibiting thymidylate synthase and disrupting RNA function
• Effect: Cytotoxic to abnormal skin cells
• Indications: Actinic keratoses, Bowen’s disease (intra-epidermal SCC)
• Brands: Efudix, Tolak

Dermatological Drugs: Dental Implications¹⁶

• Corticosteroids: ADRs!!!
• Systemic drugs for psoriasis
  • Cyclosporin: overgrown, thickened, swollen, bleeding gums
  • MTX & adalimumab: mouth ulcers & blisters, bleeding gum
• Patient education
  • Routine visits, OH, fluoride
• Retinoids ADR
  • Dry lips, mouth & skin: scaling, redness, burning, pain
  • Dry throat: hoarse voice
  • Bleeding and swollen gums

Corticosteroids: Adverse Drug Reactions (ADRs)¹⁷

• Infection
• Delayed wound healing
• Steroid rosacea
• Perioral dermatitis
• Skin atrophy
• Bruising
• Acne
• Facial flushing
• Pupura
• Depigmentation
• Telangiectasia
• Steroid induced crushing’s

Dermatological Conditions: Dental Implications¹⁸

Cold Sores (Herpes Simplex Virus Type 1)

• Highly contagious, especially during blistering/early stages
• Risk of transmission to patients and practitioners even with gloves
• Reschedule non-urgent dental treatments until healed
• Avoid aerosol-generating procedures during active lesions

Extracutaneous Warts

• May be present in the oral cavity
• Refer to oral medicine specialists for persistent or atypical lesions

Actinic Keratosis

• Rough, scaly lesions due to sun exposure
• Potential to progress to squamous cell carcinoma
• Refer for dermatological assessment if identified

Key Takeaways

• Dentists often spot conditions with broader health implications
• Prioritize infection control and early detection in practice

References¹⁹²⁰

• Ritter JM, Flower RJ, Henderson G, Loke YK, MacEwan D, Robinson E, editors. Rang & Dale’s pharmacology. 10th ed. Edinburgh: Elsevier; 2023
• Australian Medicines Handbook Online [Internet]. Adelaide (AU): Australian Medicines Handbook Pty Ltd;2000. Dermatologcicals; [updated 2025; cited 2025]. Available from: UWA Onesearch
• Pharmaceutical Society of Australia. Australian Pharmaceutical Formulary and Handbook: A Guide to Best Practice. 25th ed. Canberra: Pharmaceutical Society of Australia; 2021
• Ali K. Clinical dental pharmacology. 1st ed. Oxford: Wiley-Blackwell; 2023
• Bullock S, Manias E. Fundamentals of pharmacology. 8th ed. Frenchs Forest, NSW: Pearson Australia; 2017
• MIMS Australia. eMIMSelite: Consumer medicine information, specific clinical monograph [Internet]. Sydney: MIMS Australia; [updated 2025; cited 2025 Apr 17]. Available from: UWA Onesearch

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