Topical Pharmacology for Skin Disorders

Roadmap of Topical Drug Categories

There are eight primary categories of topical drugs utilized in the treatment of skin disorders:

• Retinoids
• Anti-infectives (Antibiotics, Antifungals, and Antivirals)
• Antiseptics and Germicides
• Corticosteroids
• Immunomodulators
• Antipsoriatics
• Enzymes and Keratolytics
• Local Anesthetics

Retinoids

Retinoids are a class of drugs chemically related to vitamin A. They are used to treat various conditions through specific biological actions.

• Actions:
  • Regulate epithelial cell growth.
  • Stimulate the growth of new blood vessels in the skin, which helps deliver nutrients to the tissue.
  • Help prevent skin cells from clogging tissue pores when applied topically.
• Uses:
  • Both systemic and topical treatment of acne vulgaris.
  • Treatment of Kaposi sarcoma.
  • Treatment of skin wrinkling.
• Adverse Reactions:
  • Local irritation, erythema (redness), and dryness.
  • Stinging, burning sensations, or itching.
  • Sensitivity to weather extremes.
• Contraindications and Precautions:
  • Contraindicated in clients with hypersensitivity to the drug or its components.
  • Contraindicated for use on damaged skin.
  • Contraindicated during pregnancy.
  • Clients must avoid sun exposure or the use of sun lamps while using retinoids.
• Interactions:
  • There are no known drug interactions for topical retinoids.

Topical Anti-Infectives

Topical anti-infectives encompass three subtypes: antibiotics, antifungals, and antivirals. Each subtype targets specific types of microorganisms.

• Antibiotic Drugs:
  • Actions: Exert a direct local effect on specific microorganisms. They are either bactericidal (killing bacteria) or bacteriostatic (inhibiting bacterial growth).
  • Uses: Treatment of primary and secondary skin infections and acne vulgaris. They also prevent infection in minor wounds such as cuts, scrapes, and burns.
• Antifungal Drugs:
  • Actions: Inhibit the growth of fungi.
  • Uses: Treatment of tinea pedis (athlete's foot), tinea cruris (jock itch), tinea corporis (ringworm), cutaneous candidiasis, and other superficial fungal infections of the skin.
• Antiviral Drugs:
  • Actions: Inhibit viral replication.
  • Uses: Treatment of initial episodes of genital herpes. They are applied directly to lesions to accelerate recovery.
• Adverse Reactions (All Subtypes):
  • Rash, itching, urticaria (hives), dermatitis, irritation, and redness.
  • Superinfection: A new infection that develops during the treatment of the original infection.
• Contraindications:
  • Known hypersensitivity to the drug or any of its components.
• Precautions in Pregnancy:
  • Topical antibiotics: Used cautiously in pregnancy $(Category\,C)$ and during lactation.
  • Acyclovir and penciclovir (antivirals): Used cautiously in pregnancy $(Category\,B)$ and during lactation.
  • Econazole (antifungal): Used cautiously in pregnancy $(Category\,B)$ and during lactation.
• Interactions:
  • There are no significant interactions known for these drugs.

Topical Antiseptics and Germicides

These agents are used primarily to reduce the presence of microorganisms on the skin.

• Definitions:
  • Antiseptic: An agent that stops, slows, or prevents the growth of microorganisms.
  • Germicide: An agent that kills bacteria.
• Actions: The specific mechanism is not well understood, but they function to reduce the number of bacteria on the skin surface.
• Uses:
  • Surgical scrubs and preoperative skin cleansers.
  • Hand hygiene.
  • Home use for cleansing skin to prevent infection in minor cuts and abrasions.
• Examples: Chlorhexidine and povidone-iodine.
• Adverse Reactions and Contraindications:
  • Adverse reaction: Allergic skin rash and itching.
  • Contraindicated in clients with known hypersensitivity to the drug or its components.
  • No significant precautions or interactions exist when used as directed.

Topical Corticosteroids

Corticosteroids are used for their potent anti-inflammatory properties when applied to the skin.

• Actions:
  • Exert localized anti-inflammatory activity.
  • Reduce itching, redness, and swelling in inflamed skin.
  • Crisaborole: A specific nonsteroidal topical medication that reduces inflammation associated with eczema by blocking the enzyme phosphodiesterase 4.
• Uses:
  • Psoriasis, dermatitis, rashes, and eczema.
  • Insect bites.
  • First-degree and second-degree burns, including sunburn.
• Localized Adverse Reactions:
  • Burning, itching, irritation, redness, and dryness of the skin.
  • Allergic contact dermatitis.
  • Secondary infection.
• Systemic Adverse Reactions: These occur with extensive or prolonged use and include:
  • Hypothalamic-pituitary-adrenal (HPA) axis suppression.
  • Cushing syndrome.
  • Hyperglycemia and glycosuria.
• Contraindications and Precautions:
  • Contraindicated for hypersensitivity.
  • Contraindicated as monotherapy for bacterial skin infections.
  • Contraindicated for use on the face, groin, and axilla.
  • Contraindicated for ophthalmic (eye) use.
  • Precautions: Use cautiously in pregnancy $(Category\,C)$ and during lactation.
• Interactions:
  • No known significant drug interactions.

Topical Immunomodulators

Immunomodulators are used to manage inflammatory and neoplastic skin conditions by altering the immune response.

• Actions:
  • Reduce inflammation by stopping the production of cytokines.
  • These drugs are not systemically absorbed.
• Uses:
  • Flare-ups of atopic eczema.
  • Actinic keratosis.
  • Genital or perianal warts.
  • Certain types of skin cancers.
• Adverse Reactions: Localized burning, itching, and skin redness.
• Contraindications and Precautions:
  • Contraindicated for immunocompromised clients.
  • Contraindicated for clients requiring long-term use of the drug.
  • Tacrolimus: Contraindicated for clients allergic to macrolide antibiotics.
  • Precautions: Use cautiously in pregnancy and lactation.
  • Safety Warning: Fluorouracil (an anticancer agent for actinic keratosis) must be kept away from children and pets.

Topical Antipsoriatics

These agents are specifically intended for the treatment of psoriasis.

• Actions and Uses: Used to remove the plaques associated with psoriasis.
• Adverse Reactions:
  • Burning, itching, and skin irritation.
  • Anthralin: May cause temporary discoloration of the hair and fingernails.
• Contraindications and Precautions:
  • Contraindicated for hypersensitivity.
  • Anthralin and calcipotriene: Used cautiously in pregnancy $(Category\,C)$ and lactation.
  • Fluorouracil: Similar to immunomodulators, must be kept away from children and pets.

Topical Enzymes and Keratolytics

This group involves drugs that physically alter or break down skin tissue.

• Topical Enzymes:
  • Actions: Aid in the removal of dead soft tissue by hastening the breakdown of proteins into simpler substances, a process known as proteolysis.
  • Uses: Treatment of necrotic tissue in chronic dermal ulcers and severely burned areas.
  • Adverse Reactions: Mild, transient pain; numbness; dermatitis.
  • Contraindications: Hypersensitivity; wounds in contact with major body cavities; wounds where nerves are exposed; fungating neoplastic ulcers.
  • Precautions/Interactions: Caution in pregnancy $(Category\,B)$ and lactation. Certain detergents may impair enzymatic activity.
• Topical Keratolytics:
  • Actions and Uses: Remove excess growth of the epidermis. Used for warts, calluses, corns, and seborrheic keratoses.
  • Adverse Reactions: Transient burning sensation, rash, dry skin, scaling. Flu-like symptoms may occur, specifically with Actinex (masoprocol).
  • Contraindications: Use on moles, birthmarks, warts with hair growth, warts on mucous membranes, or infected skin. Contraindicated for prolonged use in clients with diabetes or impaired circulation, and in infants.
  • Precautions: Caution in pregnancy $(Category\,C)$ and lactation.

Topical Local Anesthetics

Local anesthetics are applied topically to provide temporary relief from discomfort.

• Actions: Temporarily inhibit the conduction of impulses from sensory nerve fibers.
• Uses: Relieve itching and pain caused by minor burns, fungal infections, insect bites, rashes, sunburns, and plant poisoning (e.g., poison ivy).
• Examples: Benzocaine, dibucaine, and lidocaine.
• Adverse Reactions: Local irritation, dermatitis, rash, burning, stinging, and tenderness.
• Contraindications: Hypersensitivity to any component of the preparation.
• Precautions and Interactions: Use cautiously in clients receiving class I antiarrhythmic drugs such as tocainide and mexiletine. The toxic effects of these drugs are additive and potentially synergistic.

Nursing Process: Assessment

Preadministration Assessment

• Objective Data:
  • Provide a full description of skin lesions. Photography may be used for documentation.
  • Measure areas of involvement and document size, color, and appearance.
  • Assess vital signs and utilize a pain scale.
  • Record infection culture results.
  • For retinoids: Obtain a pregnancy test.
• Subjective Data:
  • Document the client's description of their condition, including sensations of pain, burning, or itching.
  • Record the onset and duration of symptoms.
  • Record allergy history, specifically drug allergies.
  • Note remedies attempted before seeking professional care.

Ongoing Assessment

• Inspect the affected area for changes and adverse reactions.
• Do not apply the drug if new changes are noted or if the client reports new problems.
• Check treatment sites $1\,\text{day}$ or more after the application.
• Report signs of extreme redness or infection at the application site.

Nursing Process: Diagnosis and Planning

Nursing Diagnoses

• Altered Skin Integrity related to the inflammatory process or increased sensitivity to the drug.
• Acute Pain related to the skin condition or drug sensitivity.
• Infection Risk related to pathogen entry into affected areas.
• Altered Body Image Perception related to changes in skin and mucous membranes.

Planning and Expected Outcomes

• Achieving an optimal response to therapy.
• Effective management of adverse drug reactions.
• Confidence in and understanding of the prescribed medication regimen.

Nursing Process: Implementation and Administration

General Implementation

• In clinical settings, apply topical drugs and manage wound devices as directed by the provider.
• Teach clients correct self-administration techniques for home use.

Administration by Drug Class

• Topical Anti-infectives: Cleanse the skin with soap and warm water before each application unless otherwise ordered. The area may be covered or left exposed.
• Topical Antifungals: Monitor for improvement. If inserting drugs vaginally, ask the client about discomfort or other sensations after insertion.
• Topical Antiseptics/Germicides: Follow provider or label instructions exactly. Use caution with clothing as iodine can stain. Do not keep these at the bedside of confused clients.
• Topical Corticosteroids: Wash the area with warm water and soap before application. Apply the drug sparingly while the skin is still moist.
• Topical Enzymes: Cleanse and prepare the area as directed. Apply wound suction devices if ordered.
• Topical Antipsoriatics: Apply carefully and only to specific lesions. Inspect application areas and report excessive irritation.
• Topical Anesthetics: Cleanse and dry the area before the first application and ensure all previous residue is removed. For oral or perioral application, instruct the client not to eat food for $1\,\text{hour}$ after use.

Nursing Process: Monitoring and Management

Monitoring Client Needs

• Altered Skin Integrity: Advise clients to keep nails short to prevent scratching damage. Use warm water and mild soap for cleaning; rinse and dry thoroughly.
• Acute Pain: Use cool, wet compresses or a bath to relieve itching. Maintain a cool environment.
• Infection Risk: Observe skin for signs of infection. If necessary, use bath oils, creams, and lotions to prevent skin from becoming dry or flaky.
• Altered Body Image Perception: Allow the client to verbalize concerns. Develop a therapeutic relationship and reassure them that treatment will cause lesions to diminish or disappear.

Client and Family Education

• General Tips: Educate on skin preparation, proper application technique, whether to cover the skin, adverse effects to watch for, and when to notify the provider.
• Retinoids: Female clients must have a negative pregnancy test within $2\,\text{weeks}$ of starting the drug and use birth control if sexually active.
• Anti-infectives: Protect skin from ultraviolet rays if using gentamicin. If using clindamycin, report severe diarrhea, stomach cramps, or bloody stools.
• Antifungals: Do not alter the frequency or amount of application without consulting a provider. For ringworm, use separate towels and cloths to prevent spreading the infection.
• Antivirals: Use a finger cot or glove during application to prevent autoinoculation of other body sites. Note that this drug does not prevent transmission of infection to others.
• Corticosteroids: Apply as a light film and rub in gently. Do not use bandages, dressings, cosmetics, or other skin products over the treated area unless directed.

Evaluation

• Therapeutic effect is achieved.
• Adverse reactions are identified, reported, and managed.
• Skin remains intact and the client is free of pain.
• No evidence of infection is observed.
• Body image perceptions are managed.
• Client and family demonstrate confidence and understanding of the drug regimen.

Questions & Discussion

Pharmacology in Practice — Topical Corticosteroids

Scenario: A client is seen at urgent care with inflamed skin resulting from severe insect bites. The primary healthcare provider has prescribed topical corticosteroid therapy.

Question: The nurse should know that which of the following is the action of a topical corticosteroid?

• A) Reduces itching, redness, and swelling
• B) Reduces the number of bacteria on the skin
• C) Prevents infection in the bite wounds
• D) Cleanses the skin thoroughly

Answer: A) Reduces itching, redness, and swelling.