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Skin disease in general practice: an overview

Thomas F Poyner
MB BS FRCP MRCGP DRCOG DPD
GP
Stockton-on-Tees
Founder member
Primary Care Dermatology Society

Sometimes primary care is seen as not coping with patients with serious "real pathology", which is viewed as the concern of secondary care. However, it has been shown that the impact of skin disease on the quality of life of patients seen in primary care is compatible with that of patients seen in secondary care.(1) This raises the question of which factors prompt referral to secondary care.
The National Institute of Clinical Evidence (NICE) has produced a guide to referrals which includes dermatology (www.nice.org.uk). There are guides for atopic eczema in children, acne and psoriasis.(2) The guides, which are currently undergoing pilot studies, give advice on referral times such as "immediate", "urgent", "soon" and "routine".
The development of future services is an area of much concern and debate. Intermediate care is seen as a way of overcoming waiting lists for secondary care and enhancing recruitment to primary care. Enhanced career opportunities for GPs, with up to 1,000 GPs taking referrals from fellow GPs by 2004, has been proposed, with dermatology being cited as one of four key areas.(3)
Technology, especially teledermatology, is seen as a way of overcoming delays in diagnosis. One can either take a single picture of the rash or lesion and then forward it, or have a video-link consultation. One study found the "store and forward" method much cheaper but clinically less effective than a "real-time" consultation.(4)
A trained nurse may be able improve the care of patients with skin diseases. Anecdotal reports suggest that primary care nurses have much to offer such patients.(5) The practice nurse could provide practical advice and demonstrate therapies. One published study involved training a practice nurse in ­dermatology who then ran a clinic attended by adults with either psoriasis or eczema. Although significance was not achieved over the control group with regard to the primary outcome measure, 20% of patients thought they had received a positive benefit from the clinic.(6)
The following offers primary care practitioners a useful guide to the pathology and treatment of specific dermatological conditions.

Acne
Acne can have a major impact on a patient's psychological wellbeing. There is also a possible link between isotretinoin and depression. When prescribing minocycline it is important to be aware of the rare risks of eosinophilic pneumonitis and a lupus-like syndrome, and if treatment with minocycline is continued for more than 6 months, patients should be monitored for hepatotoxicity and systemic lupus erythematosus. Photodynamic therapy of acne vulgaris using topical g-aminolaevulinic acid and a photo­activating light source is a possibility.(7)

Eczema
Patients with eczema have a genetic predisposition and are exposed to environmental triggers. The ­barrier function of the stratum corneum is reduced and there is increased transepidermal water loss. Topical steroids provide a therapy to overcome the acute inflammation. One can either start with a weak steroid and increase the potency, or the reverse. When it comes to treating the hands, you may frequently find that only a potent steroid is effective. One option is to reduce the ­frequency of application of the steroid rather than reduce the potency. Guidelines for the management of atopic eczema have been developed by the Primary Care Dermatology Society (PCDS) (a summary is available at: www.eguidelines.co.uk), which include:

  • General principles of primary care management.
  • The use of emollients.
  • The principles of treatment with topical steroids.
  • Bacterial infection.

Clinical Evidence is now available as a 6-monthly publication along similar lines to the BNF. Important topics covered include atopic eczema, chronic plaque psoriasis, cellulitis, erysipelas, head lice and scabies (see: www. clinicalevidence.org).

Immunomodulatory therapy for eczema
Side-effects are related to the application site, the patient' age, the potency of the steroid and the duration of the application. The skin of the face is thinner, the potential for side-effects is greater, and there is a risk of ocular complications. Interest has focused on alternatives to topical steroids, especially for inflammatory skin diseases that affect the face.
Tacrolimus is a macrolide immunosuppressant; topical tacrolimus is available in some countries, including the USA and Japan. It is prescribed for short- and long-term intermittent treatment of moderate-to-severe atopic dermatitis. A 0.03% or 0.1% ointment is used for adults, and a 0.03% ointment for children; the drug is not recommended for children under the age of 2 years. Tacrolimus can cause burning, stinging and irritation, most often in the first few days of application. If this is a problem, changing the frequency of application to daily or missing a few days can help. Tacrolimus ointment does not significantly increase the risk of viral infections, including warts, and it does not easily penetrate the thick skin of the hands and feet. As it is expensive, the cost of treatment is bound to be an area of controversy.
Pimercrolimus (SDZ ASM 981) is an ascomycin macrolactam derivative and a selective inhibitor of inflammatory cytokine release. It is under investigation for the treatment of a number of inflammatory skin conditions. A 1% cream has been used twice daily in atopic dermatitis and has been found to be effective and well tolerated. Topical pimercrolimus cream has also been shown to be effective in the treatment of chronic hand dermatitis.
Vaccines could become part of the treatment of atopic eczema, and it may even be possible to prevent atopic eczema by giving mothers probiotics in late pregnancy and during breastfeeding. Probiotics affect the gut flora, which may affect immunomodulatory mechanisms in atopic eczema. Oolong tea has been used in Japan to treat recalcitrant atopic eczema. This oral medication is thought to suppress type I and type IV allergic reactions.(8)

Psoriasis
Psoriasis used to be thought of as a disease primarily of hyperproliferation, and the major pathology was considered to be in the keratinocytes. The primary pathology is now thought probably to be a T-cell response. In plaque psoriasis there is binding of T-cells to endothelial cells and movement of T-cells from the circulation into the dermis. Activation of ­T-cells results in the release of inflammatory mediators that stimulate the keratinocytes into proliferation, resulting in the production of plaques.
Much of the advice we provide has little scientific basis. A systematic review found no firm evidence on how to treat acute guttate psoriasis.(9) Patients often ask whether they should use sunbeds to treat their plaque psoriasis. A controlled study of ultraviolet-A sunbed treatment for psoriasis showed that a short course does improve psoriasis in some patients but that the degree of improvement is small.(10) Patients who need more than occasional phototherapy are probably best referred to a dermatology unit so that they can minimise the risks and maximise the benefits of phototherapy.

Gene therapy
Genetic skin diseases may be due to a missing or defective gene, and it may be possible to introduce a genetic correction or modification. The familial diseases may be amenable to genetic interventions that block pathways associated with the production of inflammation.
The topical application of a "gene cream" would be attractive, although this may not be feasible. One possibility is a gun firing microparticles that release DNA, which then goes into keratinocytes. A direct injection approach and the grafting of genetically modified keratinocytes are other possibilities.

Infection
Treating secondary infection can improve eczema. However, there is a risk of developing resistant bacteria if antibiotics are prescribed inappropriately. Cyclical therapy with 1% hydrocortisone cream plus 2% fusidic acid and just 1% hydrocortisone cream is a safe and effective method of treating atopic eczema and is not associated with drug resistance to fusidic acid.(11)
Pityriasis rosea was originally thought to be a virus-induced skin disease.(12) However, some recent work has shown that oral erythromycin can be beneficial. In a double-blind placebo-controlled trial, a complete response was observed in 73% of the treatment group and none of the placebo group.(13)
The treatment of fungal nail disease has to be balanced against its cost and the risk of systemic ­therapies. Topical treatments for nail infections may look ­attractive as they are free from systemic side-effects and are easy to use, but they are of unknown efficacy.(14)
We know that two-thirds of common warts resolve in 2 years. This really questions the need for any active intervention. However, genital warts is a more emotive subject. Imiquimod is an effective treatment as a ­self- administered therapy for outpatient use. It can cause mild erythema and there are cost implications. A vaccine for genital herpes is being studied and may be effective for females.

Cancer
The increasing longevity of the population and the desire for sun exposure are creating an increase in consultations for actinic (solar) keratoses (see Figure 2b). Although the risk of malignant change with an actinic keratosis is small, there is a documented transformation rate to squamous cell carcinoma that warrants management of the condition. Treatment options for actinic ­keratoses in primary care include cryotherapy and 5-fluorouracil cream. While both treatment modalities are effective against actinic keratoses, 5-fluorouracil is also active against subclinical lesions that have yet to develop fully. Superficial basal cell carcinomas can also be treated with surgery or 5-fluorouracil, while the latter is additionally effective in Bowen's disease.
Photodynamic therapy has recently become available in some dermatology departments and can be used to treat Bowen's disease, superficial basal cell carcinoma and actinic keratoses.

Thalidomide
Thalidomide is a sedative that was withdrawn because of its links with fetal abnormalities. However, research with this drug has been rekindled as it inhibits ­angiogenesis and has immunomodulatory and anti-inflammatory properties. It may be effective in:(15)

  • Behçet's syndrome.
  • HIV-wasting syndrome.
  • Oral lichen planus.

The dermatology-cosmetic interface
Unwanted facial hair can be a serious problem for some women, and topical eflornithine hydrochloride cream can reduce it. The cream interferes with an enzyme involved in hair growth, resulting in slower growth. However, patients need to continue with their current physical methods of hair removal. Improvement may be seen within 4-8 weeks of treatment, but there will be a return to pretreatment levels within 8 weeks after discontinuation.
Localised excessive sweating can cause distress. Intra-dermal botulinum toxin has been advocated for excessive sweating in the axillae.16 New technology enables lasers to have more indications, and ancillary cooling systems reduce the thermal damage to non-target tissue.

References

  1. Harlow D, et al. Impaired quality of life of adults with skin disease in primary care. Br J Dermatol 2000;143:979-82.
  2. National Institute for Clinical Excellence. Referral practice. A guide to appropriate referral from general to specialist services, version under pilot study. London: NICE; 2000.
  3. Department of Health. NHS primary care, general practice and the NHS. London: DoH; 2001.
  4. Loane MA, et al. A comparison of real-time and store-and-forward tele-dermatology: a cost benefit study.Br J Dermatol 2000;143:1241-7.
  5. Kowsnacki S, Penzer R. The Quality Care Patient Interaction Project. Personal communication, October 2000.
  6. Kernick D, Cox A, Powell R, et al. A cost-consequence study of the impact of a dermatology-trained nurse on the quality of life of primary care patients with eczema and psoriasis. Br J Gen Pract 2000;50:555-8.
  7. Itoh Y, Ninomiya Y, Tajima S. Photodynamic therapy has been shown to be effective in treating intractable acne. Br J Dermatol 2001;144:575-9.
  8. Uehara M, Sugiura H, Sakurai K. A trial of oolong tea in the management of recalcitrant atopic dermatitis. Arch Dermatol 2001;137(1):42-3.
  9. Charlmers RJ, O'Sullivan T, Owen CM, Griffiths CE. Interventions for guttate psoriasis. Cochrane Databases of Systematic Reviews.
  10. Turner RJ, Walshaw D, Diffey BL, Farr PM. A controlled study of ultra-violet-A sunbed treatment for psoriasis. Br J Dermatol 2000;143:957-63.
  11. Chu T. Incidence of resistance to fusidic acid in atopic eczema patients treated with topical fusidic acid. Poster presentation, American Academy of Dermatology, 59th Annual Meeting.
  12. Kemf W, Burg G. Pityriasis rosea - a virus-induced skin disease? Arch Virol 2000;145(8):1509-20.
  13. Sharma PK, Yadav TP, Gautam,et al. Erythromycin in pityriasis rosea.J Am Acad Dermatol 2000;42:241-4.
  14. Crawford F, Hart R, Bell-Syer S,et al. Athlete's foot and fungally-infected toenails. BMJ 2001;322:288-9.
  15. Calabrese L, Fleischer AB. Thalidomide: current and potential clinical applications. Am J Med 2000;108(6):487-95.
  16. Heckmann M, Ceballos-Baumann AO, Plewig G, and the Hyperhidrosis Study Group. Botulinum toxin A for axillary hyperhidrosis (excessive sweating). N Engl J Med 2001;344:488-93.

Resources
Acne Support Group
PO Box 230
Hayes
Middlesex UB4 0UT

National Eczema Society
W:www.eczema.org

Psoriasis Association
7 Milton Street
Northampton
Northants NN2 7JG

Psoriatic Arthropathy Alliance
PO Box 111
St Albans
Herts AL2 3JQ