Corticosteroids for Atopic Dermatitis

Topical corticosteroids exert their effect through many mechanisms, including anti-inflammatory, immunosuppressive, antiproliferative, and vasoconstrictive effects.

Selecting a Corticosteroid

Consider the following factors when selecting a topical corticosteroid:

• How old is the patient?
  • In general, a less potent preparation is required in infants than in older children or adolescents. For example, for the management of flares of atopic dermatitis, a low-potency preparation (eg, hydrocortisone ointment 1% or 2.5%) usually is sufficient in an infant, while in an adolescent, a mid-potency (eg, triamcinolone 0.1%) or high-potency (eg, mometasone 0.1%) product is needed.

• What area will be treated?
  • Absorption of steroids varies with the thickness of the skin in various regions of the body.
  • Absorption is greatest in areas where the skin is thin (eg, face, perineum) and lowest where the skin is thick (eg, palms, soles). Thus, only a low-­potency preparation should be used on the face, while a mid-potency (or high-potency) product will be needed to manage dermatitis on the feet.
  • Absorption is also increased in occluded or warm and opposed areas of skin. Hence, in areas such as the axillae, groin, or diapered area of an infant, low-potency preparations are typically recommended.

How much should you dispense?

For treatment of a small area, prescribing a small tube (eg, 15 g) is sufficient; however, larger amounts may be needed. Some rules that help determine the amount to prescribe include the following:

• One gram of product covers a 10-cm x 10-cm area (perhaps 30% more coverage if an ointment is used rather than a cream). Note that 0.5 g is the amount of cream dispensed from a standard tube that extends from the tip of the adult finger to the flexural crease overlying the volar distal interphalangeal joint (this is called a finger-tip unit [FTU]).
• In an older child (6–10 years), it takes
  • 2 FTU (1 g) to cover the face and neck
  • 2.5 FTU to cover the hand and arm
  • 3.5 FTU to cover the chest and abdomen
  • 4.5 FTU to cover the foot and leg
• When managing atopic dermatitis that involves a significant portion of the body, prescribing amounts of 227 or 454 g (0.5 or 1 lb), rather than small tubes, may be necessary.

Adverse Effects

When used appropriately topical corticosteroids are very safe; however, using too potent a preparation, particularly in an inappropriate location or for too long, may result in adverse effects.

• Local adverse effects: atrophy, striae, easy bruising, hypertrichosis, and acne-like eruptions. To prevent these effects, use only low-potency preparations on the face, axillae, and groin (including the diaper area); limit the duration of use of all corticosteroids (ie, advise use “twice a day when things are bad, not at all when things are good”); and use high-potency preparations very discriminately.
• Systemic adverse effects: hypothalamic-pituitary-adrenal axis suppression, Cushing syndrome, growth restriction, glaucoma, and cataracts. Systemic adverse effects are most likely to occur when very potent agents are used (even for short periods) or when moderately potent preparations are used over large areas of the body for long periods, especially in young infants, where the ratio of skin to body surface area is larger.
  
  

The development of this information was made possible through support from Sanofi and Regeneron.