Dermatologic diseases are diagnosed by the types of lesions they cause. To make a diagnosis: ( 1) identify the type f lesion(s) the patient exhibits by morphology establishing a differential diagnosis . to obtain the elements of the history, physical examination, and appropriate laboratory tests to confirm the diagnosis. Unique clinical situations, such as the ill ICU patient, lead to different diagnostic considerations.
PRINCIPLES OF DERMATOLOGIC THERAPY
Frequently Used Treatment Measures
A. Bathing
Soap should be used only in the axillae and groin and on the feet by persons with dry or inflamed skin. Soaking in water for 10-15 minutes before applying topical corticosteroids enhances their efficacy (Soak and Smear). Bath oils can be used, but add little above the use of moisturizers, and may make the tub slippery, increasing the risk of falling.
B.Topical Therapy
Nondermatologists should become familiar with a representative agent in each category for each medication ( eg, topical corticosteroid, topical retinoid, etc)
1. Corticosteroids-
Topical corticosteroid creams, lotions, ointments, gels, foams, and sprays are presented in Table 6-2 Topical corticosteroids are divided into classes based on potency. There is little ( except price) to recommend one agent over another within the same class. For a given agent, an ointment is more potent than a cream. The potency of a topical corticosteroid may be dramatically increased by occlusion ( covering with a water-impermeable barrier) for at least 4 hours. Depending on the location of the skin condition, gloves, plastic wrap, moist pajamas covered by dry pajamas ( wet wraps) or plastic occlusive suits for patients can be used. Caution should be used in applying topical corticosteroids to areas of thin skin (face, scrotum, vulva, skin folds). Topical corticosteroid use on the eyelids may result in glaucoma or cataracts. One may estimate the amount of topical corticosteroid needed by using the “rule of nines”.In general, it takes an average of 20-30 g to cover the body surface of an adult once. Systemic absorption does occur, but adrenal suppression, diabetes n1ellitus, hypertension, osteoporosis, and other complications of systemic corticosteroids are very rare with topical corticosteroid therapy.
2. Emollients for dry skin (“moisturizers”)-
Dry skin is not related to water intake but to abnormal function of the epidermis. Many types of emollients are available. Petrolatum, mineral oil, Aquaphor, Vanicream, and Eucerin cream are the heaviest and best. Emollients are most effective when applied to wet skin. If the skin is too greasy after application, pat dry with a damp towel. Vanicream is relatively allergen-free and can be used if allergic contact dermatitis to topical products is suspected. The scaly appearance of dry skin may be improved by urea, lactic acid, or glycolic acid-containing products provided no inflammation ( erythema or pruritus) is present.
3. Drying agents for weepy dermatoses-
If the skin is weepy from infection or inflammation, drying agents may be beneficial. The best drying agent is water, applied as repeated compresses for 15-30 minutes, alone or with aluminum salts (Burow solution, Domeboro tablets).
4. Topical antipruritics-
Lotions that contain 0.5% each of camphor and menthol (Sarna) or pramoxine hydrochloride 1 % (with or without 0.5% menthol, eg, Prax, PrameGel, Aveeno Anti-Itch lotion) are effective antipruritic agents. Hydrocortisone, 1 % or 2.5%, maybe incorporated for its anti-inflammatory effect (Pramosone cream, lotion, or ointment). Doxepin cream 5% may reduce pruritus but may cause drowsiness. Pramoxine and doxepin are most effective when applied with topical corticosteroids. Topical capsaicin can be effective in some forms of neuropathic itch. Ice in a plastic bag covered by a thin cloth applied to itchy spots can be effective.
C. Systemic Antipruritic Drugs
1. Antihistamines
-H1-blockers are the agents of choice for pruritus when due to histamine, such as in urticaria. Otherwise, they appear to benefit itchy patients only by their sedating effects. Hydroxyzine 25-50 mg nightly is a typical dose. Sedating and nonsedating antihistamines are of limited value for the treatment of pruritus associated with inflammatory skin disease. Agents that may treat pruritus better include antidepressants (such as doxepin, mirtazapine, and paroxetine) as well as agents that may act either centrally or peripherally directly on the neurons that perceive or n1odulate pruritus (such as gabapentin, pregabalin, and duloxetine). Aprepitant and opioid antagonists such as naltrexone and butorphanol can be very effective in select patients, but their exact role in the management of the pruritic patient is not yet defined.
2. Systemic corticosteroids
References
American Academy of Dermatology. Medical student core curriculum. http:/ /www.aad.org/ education-and-quality-care/ medical-student-core-curriculum Apfelbacher CJ et al. Oral H 1 antihistamines as monotherapy for eczema. Cochrane Database Syst Rev. 2013 Feb28;2: CD00770. [PMID: 23450580] Berger TG et al. Pruritus in the older patient: a clinical review. JAMA. 2013 Deel 1;310(22): 2443-50. [PMID: 24327039] Elmariah SB et al. Topical therapies for pruritus. Semin Cutan Med Surg. 2011 Jun;30(2):118-26. [PMID: 21767774] Stander S et al. Medical treatment of pruritus. Expert Opin Emerg Drugs. 2012 Sep;l7(3):335-45. [PMID: 22870909] Steinhoff Metal. Pruritus: management algorithms and experimental therapies. Semin Cutan Med Surg. 2011 Jun;30(2): 127-37. [PMID: 21767775] .
Sunscreens
Protection from ultraviolet light should begin at birth and will reduce the incidence of actinic keratoses, melanoma, and some nonmelanoma skin cancers when initiated at an)1 age. The best protection is shade, but protective clothing, avoidance of direct sun exposure during the peak hours of the day, and daily use of chemical sunscreens are important.
Fair-complexioned persons should use a sunscreen with an SPF (sun protective factor) of at least 15 and preferably 30-40 every day. Sunscreens with high SPF values (> 30) usually afford some protection against UV A as well as UVB and are helpful in managing photosensitivity disorders. The actual SPF achieved is about one-quarter or less than that listed on the product, since patients apply only one-qu.arter as much sunscreen per unit area when compared with the amount used in tests to determine the listed SPF. Repeated daily applications enhance sunscreen efficacy. Aggressive sunscreen use should be accompanied by vitamin D supplementation in persons at risk for osteopenia ( eg, organ transplant recipients).
References
Bodekrer M et al. Accumulation of sunscreen in human skin after daily applicatio11s: a stt1dy of sunscreens with different ultraviolet radiation filters. Photodermatol Photoimmunol Photomed. 2012 Jun;28(3):127-32. [PMID: 22548393] Jou PC et al. UV protection and sunscreens: what to tell patients. Cleve Clin J Med. 2012 Jun;79(6):427-36. [PMID: 22660875j Liu W et al. Sunburn protection as a function of sunscreen a_ppU-cation thickness differs between high and low SPFs. Photodermatol Photoimmunol Photomed. 2012 Jun;28(3):120-6. [PMID: 22548392] Mar V et al. Nodular melanoma: a distinct clinical entity and the largest contributor to melanoma deaths in Victoria, Australia. J Am Acad Dermatol. 2013 Apr;68(4):568-75. [PMI.D: 23182058] Ou-Yang H et al. High-SPF sunscreens (SPF>70) may provide ultraviolet protection above minimal recommended levels by adequately compensating for lower sunscreen user application amounts. J Am Acad Dermatol. 2012 Dec;67(6):1220-7. [PMID:22463921].Petersen B et al. Sunscreen use and failures-on site observations on a sun-holiday. Photochem Photobiol Sci. 2012 Dec13;12(1):190-6. [PMID: 23023728] Robinson JK et al. Prevention of melanoma with regular sunscreen use. JAMA. 2011 Jul20;306(3 ):302-3. [PMID: 21712528]
Complications of Topical Dermatologic Therapy
Complications of topical therapy can be largely avoided. They fall into several categories allergy, irritation, and overuse.
A. Allergy
Of the topical antibiotics, neomycin, and bacitracin have the greatest potential for sensitization. Diphenhydramine, benzocaine, vitamin E, aromatic essential oils, bee pollen, preservatives, fragrances, and even the topical corticosteroids themselves can cause allergic contact dermatitis.
B. Irritation
Preparations of tretinoin, benzoyl peroxide, and other acne medications should be applied sparingly to the skin.
C. Overuse
Topical corticosteroids may induce acne-like lesions on the face (steroid rosacea) and atrophic striae in body folds.