Acta Dermato-Venereologica 99-1CompleteContent | Page 15

CLINICAL REPORT
47
Rosacea and Demodicosis: Little-known Diagnostic Signs and
Symptoms
Fabienne M. N. FORTON 1 and Viviane DE MAERTELAER 2
Dermatology Clinic, and 2 Institute of Interdisciplinary Research in Molecular Biology, Biostatistics Department, Université libre de Bruxelles,
ULB, Brussels, Belgium
1
Papulopustular rosacea and demodicosis are characte-
rized by non-specific symptoms, which can make clini-
cal diagnosis difficult. This retrospective study of 844
patients assessed the diagnostic importance of clini-
cal signs and symptoms that are poorly recognized as
being associated with these conditions. In addition to
well-known signs (vascular signs (present in 80% of
patients), papules (39%), pustules (22%) and ocular
involvement (21%)), other signs and symptoms (dis-
creet follicular scales (93%), scalp symptoms (pruri-
tus, dandruff or folliculitis; 38%) and pruritus (15%))
may also suggest a diagnosis not only of demodico-
sis, but also of papulopustular rosacea. Facial Demo-
dex densities (measured by 2 consecutive standardi-
zed skin biopsies) were higher when ocular or scalp
involvement was present, suggesting more advanced
disease, but further investigations are needed to con-
firm this hypothesis. Recognition of these clinical signs
and symptoms should encourage dermatologists to
perform a Demodex density test, thus enabling appro-
priate diagnosis to be made.
Key words: Demodex;
scalp; dandruff; pruritus.
rosacea;
SIGNIFICANCE
Papulopustular rosacea and demodicosis are common facial
skin conditions that can be difficult to diagnose clinically.
In addition to well-known clinical signs, such as vascular
signs and papules, in our study of patients with known pa-
pulopustular rosacea or demodicosis, we showed that other
clinical signs (discreet facial follicular scales, dandruff, fol-
liculitis on the scalp, facial or scalp pruritus) are also fre-
quently present. Presence of these signs and symptoms
should therefore encourage dermatologists to perform
further diagnostic tests (e.g., the recently described test
based on the high density of Demodex mites observed in
these conditions), to ensure accurate diagnosis.
The diagnosis of PPR and demodicosis from clinical
signs alone can be difficult, but can be confirmed using
a new diagnostic test (30) based on the high skin Demo-
dex density (Dd) in these patients (30–36). In addition
to well-known clinical signs, many patients with PPR
demodicosis;
Accepted Sep 18, 2018; Epub ahead of print Sep
18, 2018
Acta Derm Venereol 2019; 99: 47–52.
Corr: Fabienne Forton, Dermatology Clinic, rue Frans Binjé,
8, BE-1030 Brussels, Belgium. E-mail: fabienne.forton@
skynet.be
P
apulopustular rosacea (PPR) and de-
modicosis are common skin conditions
with non-specific signs and symptoms (1–3).
PPR is characterized mainly by central face
distribution of persistent erythema and pa-
pulopustules (1, 2) (Fig. 1). Most cases of
demodicosis are pityriasis folliculorum (Fig.
2) or rosacea-like demodicosis (3–7), this
being considered by some authors as the
same disease as PPR (8–11). Less frequently,
demodicosis can manifest as folliculitis or
abscesses (3, 12–15), hyperpigmentation
(3, 5, 16), follicular eczematids (defined as
erythema, dilated pores, granular skin, some
papules and non-follicular scales) (3), isola-
ted inflammatory papules (3, 17), and ocular
demodicosis (5, 16, 18–29).
Fig. 1. A 25-year old man with papulopustular rosacea and extensive demodicosis
involving the entire head. (A, C) Papulopustular rosacea on the face; (B) typical
cylindrical dandruff at the base of the eyelashes (black arrows); (B, D) visible pityriasis
folliculorum (blue arrows) on the upper left eyelid and on the pre-auricular zone; (D)
papulopustular rosacea involving the left ear lobe. He also had dandruff on the scalp.
SSSB1+SSSB2 values are indicated on the figure. Patient permission was obtained. This
patient, seen recently, was not included in the study.
This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta
Journal Compilation © 2019 Acta Dermato-Venereologica.
doi: 10.2340/00015555-3041
Acta Derm Venereol 2019; 99: 47–52