About half of nails with suspected fungus do not have a fungal infection. Because other nail conditions, such as nail dystrophies, may look similar in appearance, it is important to ensure accurate diagnosis of nail disease before beginning treatment.

By confirming a fungal infection, patients are not inappropriately at risk for the side-effects of antifungal therapy, and nail disease is correctly treated. 

Ameen M, Lear JT, Madan V, Mohd Mustapa MF, Richardson M. British Association of Dermatologists’ Guidelines for the Management of Onychomycosis 2014. British Journal of Dermatology 2014; 171(5): 937-958.

Mehregan DR, Gee SL. The cost effectiveness of testing for onychomycosis versus empiric treatment of onychodystrophies with oral antifungal agents. Cutis 1999; 64(6): 407–10.

Patients with early, thin melanoma, such as melanoma in situ, T1a melanoma, or T1b melanoma ≤ 0.5mm, have a very low risk of the cancer spreading to the lymph nodes or other parts of the body. Further, patients with early, thin melanoma have a 97 per cent five-year survival rate, which also indicates a low risk of the cancer spreading to other parts of the body. As such, the performance of sentinel lymph node biopsy is unnecessary.

Additionally, baseline blood tests and radiographic studies (e.g. chest radiographs, CT scans, and PET scans) are not the most accurate tests for the detection of cancer that is spreading because they have high false-positive rates. These tests have only shown benefit when performed as indicated for suspicious signs and symptoms based on the patient’s history and physical exam.

Bichakjian CK, Halpern AC, Johnson TM, Foote Hood A, Grichnik JM, Swetter SM, Tsao H, VH, Chuang TY, Duvic M, Ho VC, Sober AJ, Beutner KR, Bhushan R, Smith Begolka W. American Academy of Dermatology: Guidelines of care for the management of primary cutaneous melanoma. Journal of the American Academy of Dermatology 2011; 65(5): 1032–47.

National Comprehensive Cancer Network. National Comprehensive Cancer Network clinical practice guidelines in oncology (NCCN Guidelines®): melanoma. Revised 2012. Fort Washington (PA): NCCN, 2012.
 

In healthy individuals, the use of Mohs micrographic surgery for low-risk, small (< 1cm), superficial or non-aggressive (based on appearance under a microscope) squamous cell carcinomas and basal cell carcinomas is inappropriate for skin cancers on the trunk and extremities.

In these areas of the body, the clinical benefits of this specialized surgical procedure do not exceed the potential risks. It is important to note that Mohs micrographic surgery may be considered for skin cancers that appear on the hands, feet, ankles, shins, nipples, or genitals because they have been shown to have a higher risk for recurrence or require additional surgical considerations.

Connolly SM, Baker DR, Coldiron BM, Fazio MJ, Storrs PA, Vidimos AT, Zalla MJ, Brewer JD, Smith Begolka W; Ratings Panel, Berger TG, Bigby M, Bolognia JL, Brodland DG, Collins S, Cronin TA Jr, Dahl MV, Grant-Kels JM, Hanke CW, Hruza GJ, James WD, Lober CW, McBurney EI, Norton SA, Roenigk RK, Wheeland RG, Wisco OJ. Appropriate use criteria for Mohs micrographic surgery: a report of the American Academy of Dermatology, American College of Mohs Surgery, American Society for Dermatologic Surgery Association, and the American Society for Mohs Surgery. Journal of the American Academy of Dermatology 2012; 67(4): 531–50

National Comprehensive Cancer Network. National Comprehensive Cancer Network clinical practice guidelines in oncology (NCCN Guidelines®): Basal cell and squamous cell skin cancers. Revised 2011 February. Fort Washington (PA): NCCN, 2011..
  

The presence of high numbers of the staphylococcus aureus bacteria on the skin of children and adults with atopic dermatitis is common. It is widely believed that staph bacteria may play a role in causing skin inflammation, but the routine use of oral antibiotic therapy to decrease the amount of bacteria on the skin has not been definitively shown to reduce the signs, symptoms (e.g. redness, itch), or severity of atopic dermatitis. In addition, if oral antibiotics are used when there is not an infection, it may lead to the development of antibiotic resistance.

The use of oral antibiotics can also cause side effects, including hypersensitivity reactions, or exaggerated immune responses such as allergic reactions. Although it can be difficult to determine the presence of a skin infection in atopic dermatitis patients, oral antibiotics should only be used to treat patients with evidence of bacterial infection in conjunction with other standard and appropriate treatments for atopic dermatitis.

Bath-Hextall JF, Birnie AJ, Ravenscroft JC, Williams JC. Interventions to reduce Staphylococcus aureus in the management of atopic eczema: an updated Cochrane review. British Journal of Dermatology 2010; 163: 12–26.    

The use of topical antibiotics on clean surgical wounds has not been shown to reduce the rate of infection compared to the use of non-antibiotic ointment or no ointment. Topical antibiotics can aggravate open wounds, hindering the normal wound-healing process.

When topical antibiotics are used in this setting, there is a significant risk of developing contact dermatitis, a condition in which the skin becomes red, sore, or inflamed after direct contact with a substance, along with the potential for developing antibiotic resistance. Only wounds that show symptoms of infection should receive appropriate antibiotic treatment.

Dixon AJ, Dixon MP, Dixon JB. Randomized clinical trial of the effect of applying ointment to surgical wounds before occlusive dressing. British Journal of Surgery 2006; 93(8): 937–43.

Smack DP, Harrington AC, Dunn C, Howard RS, Szkutnik AJ, Krivda SJ, Caldwell JB, James WD. Infection and allergy incidence in ambulatory surgery patients using white petrolatum vs bacitracin ointment. A randomized controlled trial. Journal of the American Medical Association 1996; 276(12): 972–7.

Campbell RM, Perlis CS, Fisher E, Gloster HM Jr. Gentamicin ointment versus petrolatum for management of auricular wounds. Dermatologic Surgery 2005; 31(6): 664–9.
   

Sheth VM, Weitzul S. Postoperative topical antimicrobial use. Dermatitis 2008; J19(4): 181–9.

Gehrig KA, Warshaw EM. Allergic contact dermatitis to topical antibiotics: epidemiology, responsible allergens, and management. Journal of the American Academy of Dermatology 2008; 58(1): 1–21.