INTRODUCTION

A wide variety of skin diseases exist, many of which are treated not only by dermatologists but also by general physicians, paediatricians and other healthcare providers.^{1, 2} Some skin diseases require specialist treatment. Consequently, patients with these conditions are often referred from general primary clinics and primary dermatological clinics to other medical institutions for further secondary or tertiary care. However, it has not been fully evaluated at those clinics, which skin conditions necessitate such referrals. Several surveys have indicated that skin diseases are not managed by only dermatologists.^3-9 Therefore, identifying which skin conditions often require specialised care beyond primary treatment could be invaluable for many clinicians. In Japan, patients can visit primary dermatological clinics directly without first consulting general primary care physicians, and some are referred from those primary dermatological clinics to other medical institutions for various reasons. We investigated the referral patterns, by skin disease categories, from a primary dermatological clinic to other medical institutions. The Ueo Dermatology Clinic in Saiki City, Oita, Japan, which is the sole clinic specialising in dermatology in the area (2022 population: 67,126), served as the study site. Using the clinic's medical records, we analysed which skin diseases or disease categories were most frequently referred to other medical institutions. This study aims to identify skin conditions that often require further care when treated at a primary dermatological clinic. Although this survey was conducted in a primary dermatological clinic rather than a general clinic, it would be beneficial for many clinicians to know which skin conditions are not resolved at a primary dermatological clinic.

METHODS

RESULTS

Referral patterns from a primary dermatological clinic to other medical institutions on patients with certain skin diseases

Table 2 summarises the patient numbers and referral rates for each disease category. 'Eczema and dermatitis' was the most frequently seen category (Table 2); indeed, the top-three indications treated in the clinic were 'atopic dermatitis,' 'contact dermatitis' and 'acute eczema' (Table 1). Next, we visualised the critical categories for referrals by generating scatter plots with the numbers of all patients and referrals by disease category (Figures 1 and 2). For general referrals, the categories 'Malignant skin tumours and melanomas' and 'Benign skin tumours' showed high numbers of referrals, even though the combined number of patients in these categories was less than 1000 (Figure 1). For emergency referrals, the number of referrals for the category 'Viral infections' was the highest, followed by those for 'Drug-induced skin reactions' and 'Bacterial infections' (Figure 2). With regard to actual diseases, as shown in Table 1, the number of basal cell carcinoma, squamous cell carcinoma, epidermal cyst and subcutaneous tumour reflected high general referral numbers; the number of herpes zoster, drug-induced skin reactions and cellulitis reflected high emergency referral numbers, in each category. Although low numbers, the rates for general and emergency referrals were high in the categories of 'Blistering Diseases,' 'Connective Tissue Diseases' and 'Vasculitis, Purpura and Other Vascular Diseases' (Table 2). The reasons for the referrals are presented in Supporting Information: Table S2. For both general and emergency referrals, the need for consultation with doctors in departments other than dermatology ranked high among the reasons for referrals. Based on our findings, we provide a summary of the key skin disease categories at a primary dermatological clinic requiring referral to other medical institutions (Supporting Information: Figure S1).

Table 2. Referral rates by the skin disease categories.

Category of dermatological disordera	Major diseases included in each categoryb	Cases (n)/general referral rates/emergency referral ratesc
Eczema and dermatitis	Atopic dermatitis, acute eczema, contact dermatitis and seborrhoeic dermatitis	4495/0.24%/0.02%
Viral infections	Verruca vulgaris, herpes zoster, herpes simplex and molluscum contaginosum	1567/0.38%/2.36%
Disorders of the skin appendages	Acne vulgaris, rosacea and alopecia areata	1325/1.36%/0.00%
Fungal diseases	Tinea pedis, tinea unguium, Candida intertrigo and malassezia folliculitis	1233/0.00%/0.00%
Urticaria, prurigo, and pruritus	Urticaria, acute prurigo and chronic prurigo	961/0.21%/0.10%
Skin diseases caused by arthropods and other noxious animals	Insect bite, tick bite and caterpillar dermatitis	948/0.00%/0.00%
Benign skin tumours	Seborrhoeic keratosis, epidermal cyst, pyogenic granuloma and ganglion	903/6.31%/0.00%
Bacterial infections	Cellulitis, impetigo, folliculitis and furuncle	697/0.14%/1.15%
Disorders of keratinisation	Ichthyosis vulgaris, psoriasis vulgaris, callus and clavus	557/1.44%/0.18%
Physicochemical injury	Burn, traumatic injury, pernio and ulcer	457/0.44%/0.88%
Others	Aphtha, cheilitis, neuropathy and psychiatric disorders	212/10.85%/1.42%
Drug-induced skin reactions	Drug-induced skin reaction and fixed drug eruption	205/1.95%/4.39%
Pustular diseases	Palmoplantar pustulosis	205/9.27%/0.00%
Disorders of skin colour	Vitiligo vulgaris, melasma and senile lentigo	121/6.61%/0.00%
Erythema, erythroderma	Erythema multiforme, eczematous erythroderma, erythema annulare centrifugum and Stevens–Johnson syndrome	72/5.56%/6.94%
Malignant skin tumours and melanomas	Squamous cell carcinoma, basal cell carcinoma, actinic keratosis and Bowen's disease	70/75.71%/1.43%
Nevi and neurocutaneous syndrome	Melanocytic nevi, nevus of Ota and sebaceous nevus	70/20.00%/0.00%
Vasculitis, purpura, and other vascular diseases	IgA vasculitis, pigmented purpuric dermatosis, senile purpura and purpura simplex	62/11.29%/4.84%
Photosensitive diseases	Photosensitivity and sunburn	51/0.00%/0.00%
Metabolic disorders	Lichen amyloidosis and xanthelasma palpebrarum	39/5.13%/0.00%
Blistering diseases	Bullous pemphigoid	24/20.83%/8.33%
Disorders of the dermis and subcutaneous fat	Erythema nodosum and granuloma annulare	21/14.29%/0.00%
Connective tissue diseases	Discoid lupus erythematosus, systemic lupus erythematosus, localised sclerosis and dermatomyositis	10/20.00%/10.00%
Mycobacterial infections	Mycobacterium marinum	1/0.00%/0.00%

• ^a All skin diseases treated in the Ueo Dermatology Clinic were classified into a category. The categories are arranged in descending order of the number of patients.
• ^b Major diseases from each category, treated at Ueo Dermatology Clinic, are listed, with up to four diseases per category.
• ^c The number of patients of each category treated in the Ueo Dermatology Clinic, and general and emergency referrals rates (percentages; calculated as referral cases/total cases in each category × 100) are shown.

DISCUSSION

Although several studies have investigated referred patients with skin conditions at hospitals, including urgent consultations at dermatology departments, surveys at primary dermatological clinics like this study are lacking.^10-14 The differences between the results at a primary dermatological clinic and those at hospitals are interesting. The results of cutaneous infection, including herpes zoster and cellulitis and cutaneous adverse drug eruptions are shared between a primary dermatological clinic and hospitals. Indeed, multiple severe complications of herpes zoster are known, for example, acute encephalitis, keratitis and motor paralysis, resulting in severe prognoses.^{15, 16} Moreover, cellulitis is the most common reason for skin-related hospitalisation¹⁷; sometimes, urgent drug change or discontinuation should be considered for patients with adverse drug eruptions, requiring hospitalisation or consultation with physicians of departments other than dermatology.^18-20 These match the reasons for emergency referrals (Supporting Information: Table S2). On the other hand, eczema occupied a large number of referred patients with skin conditions at hospital analyses,^10-14 but not our analysis. Although this discrepancy may be caused by the fact that this survey was conducted at a dermatological clinic, multiple referred patients with eczema were included in our survey (Figure 1); however, more than that, numerous patients with eczema were treated at our clinic. Conversely, skin tumours are inconspicuous in hospital analyses because of their low number.^10-14 Analyses at hospitals are precious, but our survey at a primary dermatological clinic highlights skin conditions during primary care. Notably, 'Blistering Diseases,' 'Connective Tissue Diseases,' and 'Vasculitis, Purpura, and Other Vascular Diseases' were very rare in both surveys. However, they showed high rates of referrals from the primary dermatological clinic to other medical institutions. This information allows general primary clinicians to judge smooth referrals to other medical institutions for further secondary or tertiary care.

This study had two limitations, as follows. (i) This study was performed in Japan, and disease epidemiology and the medical system's response will vary by region and country. (ii) The results of the present study were derived from a single institution and dermatologist.

This study identified several skin conditions often requiring additional care when treated at a primary dermatological clinic. Based on these findings, seamless cooperation between primary clinics and specialised medical institutions is anticipated.

AUTHOR CONTRIBUTIONS

Conceptualization: Takashi Sakai. Data curation: Daisuke Ueo. Formal analysis: Erika Ochiai and Jun Sese. Investigation: Daisuke Ueo. Methodology: Takashi Sakai. Project administration: Takashi Sakai. Resources: Daisuke Ueo. Supervision: Takashi Sakai and Yutaka Hatano. Visualisation: Daisuke Ueo, Takashi Sakai, Erika Ochiai, and Jun Sese. Writing—original draft preparation: Daisuke Ueo and Takashi Sakai. Writing—review and editing: All authors.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflict of interest.

ETHICS STATEMENT

This study was approved by the ethics committee of the Oita University Faculty of Medicine and was performed in accordance with the principles of the Declaration of Helsinki and its subsequent amendments. This study employed the opt-out method for patient consent.