Chapter 50 Topical steroids
1. When were corticosteroids discovered? When were they first used therapeutically?
• 1948: First reported use of cortisone and adrenocorticotropic hormone (ACTH) in the treatment of rheumatoid arthritis
3. How is the potency of topical steroid medications determined?
At present, the most widely used topical steroid ranking system of potency is based on the vasoconstrictor assay, where test medications are applied in serial dilutions to the forearms of the volunteers for a standard length of time. Many believe that this one measure of biologic function correlates with clinical effectiveness. Although it is difficult to compare studies because of a lack of standardization, a recent study demonstrated that therapeutic index did not correlate with the vasoconstrictor assay or clinical outcome.
4. How do topical steroids inhibit cutaneous inflammation?
The steroid molecule binds to specific cytoplasmic steroid receptors that are transported to the cell nucleus, where it interacts with high-affinity binding sites on nuclear DNA. Steroid-induced proteins, called lipocortins, are then synthesized by the target cells. There is good evidence that these proteins inhibit phospholipase A2, an enzyme necessary for formation of inflammatory mediators (e.g., arachidonic acid, prostaglandins, leukotrienes, and platelet-activating factor) that decrease vascular permeability. Another immediate effect of topical steroids is to produce vasoconstriction, thus decreasing tissue edema, erythema, and heat. The steroid molecule can also bind to cell membranes, altering their function. Inflammatory cells show reduced migration and function at sites of inflammation.
5. How are topical corticosteroids classified as to potency?
Many authors in the United States classify topical corticosteroids into seven categories of potency: 1) superpotency, 2) high potency, 3) high midpotency, 4) midpotency, 5) low midpotency, 6) mildly potent, and 7) low potency. The authors of this book prefer to rank them into four classes of potency (Table 50-1).
6. How many topical steroid medications are available in the United States?
Group III: Midpotency (antiinflammatory activity = 10–100)
Epocrates Rx lists over 100 brand name and generic topical products that contain corticosteroids; this does not include the various vehicles and concentrations. It is not necessary to learn all of the steroid names and preparations. Familiarity with one preparation in each potency class is often sufficient.
Group II: High Potency (antiinflammatory activity = 100–500)
| Group I: Super Potency (antiinflammatory activity = 500) |
OTC, Over-the-counter.
* The individual steroid molecules can be moved up or down in the potency ranking by changing the vehicle of the topical formulation.
Epocrates Rx (database for Parental Drug Association [PDA]), Version 1.0: Epocrates, Inc, San Mateo, CA. Copyright 2006 [updated Dec 14, 2009; cited Dec 14, 2009]. Available from: http://www.epocrates.com.
7. What are the differences between brand name and generic topical steroid products?
8. With so many products available, how do you decide which product to prescribe for your patient?
There are anatomic site differences in relative absorption: forearm = 1, back = 1.7, sole = 0.14, palm = 0.83, scalp = 3.5, cheek = 13, eyelid and scrotum = 42. A multitude of additional factors must be considered, including: chronicity of disease being treated, percentage of body surface involvement, patient age, specific medication, vehicle, frequency of application and technique, potential side effects, presence of coexisting factors, and cost. Importantly, if the product is unpleasing, patient compliance may be compromised.
9. What specific directions should be provided when prescribing super-, high-, and midpotency topical steroids?
10. Why is the vehicle important when recommending a topical corticosteroid?
The choice of vehicle may affect several factors that relate to potency, including bioavailability, lipid solubility, and the partition coefficient of each product. A vehicle should also be selected based on indication, disease severity and extent, body region to be treated, as well as patient preference. A steroid molecule in an ointment base will result in the most potent preparation, because it is the most occlusive with the greatest penetration. This is followed by creams, lotions, solutions, gels, and sprays. Compounding, dilution, or addition of ingredients to a proprietary product should be discouraged. This practice can affect the uniformity, stability, and/or bioavailability of the active ingredient. Also, the cost is greater because additional labor is required.
11. Are certain vehicles preferred for particular types of lesions or anatomic sites?
Ointments work best on chronic, thickened skin lesions and should be avoided when the dermatosis is acute, vesicular, and weeping. Solutions, gels, sprays, or foams are recommended for dermatoses in hairy areas. Creams or lotions are best for intertriginous locations. Gels and sprays can also be used to treat inflammatory lesions on mucosal surfaces.
12. A patient has 5% total body surface area (TBSA) involvement. How much topical steroid should be prescribed for twice daily application for a 1-week-on and 1-week-off treatment cycle? The patient will return in 4 weeks for follow-up.
Topical medications are frequently under- or overprescribed, and only a thin layer of medication is necessary. Use the fingertip unit (FTU) application technique and percent of TBSA to calculate the amount needed: 1 FTU equals approximately 0.5 gm of medication and will treat 2% TBSA in the average adult. The patient will need approximately 35 grams for the next 4 weeks. Calculation: (5% TBSA/1 application) × (1 FTU/2% TBSA) × (0.5 grams/1 FTU) × 14 day × (2 applications/1 day) = 35 grams.
NOTE: One FTU is the amount of medication expressed from a tube with a 5-mm opening that extends from the distal interphalangeal crease to the tip of the finger (Fig. 50-2). One palm size, including fingers, represents 1% TBSA.
14. When are combination topical steroid and antiinfective products indicated?
The combination products are often marginally effective and expensive. The most commonly prescribed products are Mycolog II (nystatin/triamcinolone) and Lotrisone (clotrimazole/betamethasone). Lotrisone is approved by the U.S. Food and Drug Administration (FDA) for tinea cruris/corporis/pedis in adults and children more than 12 years of age.
17. What are the effects of topical steroids on the epidermis?
Thinning of the epidermis can occur within 7 days of use of superpotent topical steroids. After 3 weeks of potent topical steroid use, all layers of the epidermis are reduced in thickness by about one half. The thinning of the epidermis, particularly the stratum corneum, impairs the barrier function of the epidermis, thus increasing transepidermal water loss and skin irritancy.
18. What are the effects of topical steroids on the dermis?
Within 1 to 3 weeks of using superpotent topical steroids, the dermal volume is measurably reduced. This is due to decreased fibroblast production of dermal ground substance, primarily hyaluronic acid, and decreased dermal water content. Abnormal synthesis of collagen and elastin results in dermal atrophy (Fig. 50-3), skin fragility, striae (Fig. 50-4), telangiectasias, poor vascular support with skin purpura, and decreased wound healing.
19. What are the systemic side effects of topical steroid therapy?
The superpotent topical steroids are over a thousand times more potent than hydrocortisone. Infants and children are more at risk for systemic side effects because they have greater surface-to-body ratio than adults, and they may not be able to metabolize the steroid molecule efficiently.
| LOCAL CUTANEOUS SIDE EFFECTS | SYSTEMIC SIDE EFFECTS |
|---|---|
Figure 50-3. Cutaneous atrophy and slight hypopigmentation from intralesional corticosteroids.
(Courtesy of the Fitzsimons Army Medical Center teaching files.)
Adults can show hypothalamic-pituitary-adrenal (HPA) axis suppression within 3 to 4 days by use of as little as 7.5 gm of superpotent topical steroid daily. However, it is rare to see clinical Cushing’s syndrome in an adult patient. Superpotent topical steroids are not recommended for children under age 12 (see Table 50-2).
20. Are there topical steroid addicts?
Yes. These patients often present with a mild dermatitis that respond well to topical steroids. However, when the topical steroid is discontinued, the symptoms quickly return and are more profound. Thus, the patient is reluctant to discontinue the steroid use despite the perpetuation of the syndrome.
21. What is periorificial dermatitis?
Periorificial dermatitis is frequently associated with the inappropriate use of topical steroids (Fig. 50-5). It occurs most commonly in adult, fair-skinned caucasian women who have a family history of rosacea. The rash is characterized by inflammatory follicular papules and pustules with a background of erythema and scaling located on the chin, perioral, and perinasal skin, and less commonly on the eyelids. Most patients respond well to discontinuation of the topical steroid and oral antibiotics of the tetracycline class for 4 to 6 weeks. Some patients flare when the steroid is discontinued, and some have recurrences.
22. What is tinea incognito?
The symptoms produced by dermatophyte infections are due to the body’s immune response to the offending fungal organism. Topical steroids decrease the inflammatory response and initially alleviate the symptoms. In decreasing the body’s defense mechanisms, however, they allow the organism to proliferate, alter the typical clinical picture, and delay the correct diagnoses.
Key Points: Topical Steroids
1. Approximately 2% total body surface area (TBSA) requires 1 fingertip unit (FTU) or 0.5 gram of topical steroid medication. One percent of the patient’s TBSA can be estimated as 1 palmar surface, including the fingers.
2. Provide written instructions and demonstration of proper FTU application technique to enhance compliance when using topical steroids. Specifically indicate that only low-potency topical steroids may be used in areas of thin skin (i.e., face, neck, axilla, inframammary, infrapannus, groin).
3. Tachyphylaxis may develop with prolonged use of topical steroids. To avoid this, recommend intermittent pulse dosing (i.e., 1 week of “rest” between weekly treatment periods).
23. Can topical steroid medications cause contact dermatitis?
24. Mrs. Jones brings her 9-month-old infant with moderate atopic dermatitis to your office. What topical steroid do you prescribe?
Only low-potency steroids should be used in children under age 1. Once-daily application limited to areas of active inflammation after bathing is often sufficient, and the product should not be used more than twice daily. The treatment regimen should include skin lubrication to prevent rapid evaporation and transepidermal water loss. Oral antihistamines are often necessary for pruritus.
25. A 40-year-old woman presents with a 5-year history of chronic dermatitis on her palms. Lesions are plaques with abundant scale. What topical steroid do you prescribe?
Superpotent topical steroid is indicated because of the severity of disease. Additionally, the palmoplantar surfaces have reduced absorption when compared to other anatomic sites. The patient should be downgraded to a high- or midpotency topical when lesional thickness is improved. Proper lubrication and hand protection from irritants are also important for therapeutic success. If the patient requires prolonged treatment with high- or superpotency topical steroids, then alternating with nonsteroid therapies, such as topical tar or phototherapy, should be considered.
26. A 35-year-old woman with moderate psoriasis presents with scalp, facial, and body plaque lesions. What topical steroid do you prescribe?
Prescribe more than one topical steroid for this patient. A high-potency topical steroid lotion or solution would be recommended for the scalp, a low-potency cream for the face, and a high- or superpotency ointment for the trunk and extremities. When the psoriasis improves, the steroid can be downgraded to a lower-potency product or fewer applications. Topical steroid holidays or alternate treatments (i.e., anthralin, tar, vitamin D analog, phototherapy, methotrexate, biologics) should be considered for difficult chronic cases.
27. Mrs. Smith brings her 6-month-old infant with a 2-week history of diaper dermatitis to your office. What topical steroid do you prescribe? Would you recommend any other topical therapy?
For the diaper area, use only a low-potency topical steroid applied three times daily for no more than 7 to 10 days. The diaper area has air-tight occlusion, increasing the risk of local and systemic side effects (see Table 50-2). Any diaper dermatitis that has persisted for more than 3 days should be treated for secondary candidal infection. Avoid use of combination steroid/antifungal preparations.
