This document describes a study analyzing the differential diagnosis of six erythemato-exfoliative skin disorders (PR, P, LP, CD, SD, PRP) using a database of 366 patients. Statistical analysis identified distinctive clinical and histopathological attributes that helped design an algorithm to diagnose the disorders. The algorithm achieved over 95% correct diagnosis, though had difficulty distinguishing PR from SD. Key attributes differentiating the disorders included definite borders, thinning of the epidermis, elongation of rete ridges, and presence of follicular papules or plugs.

1. Differential Diagnosis
of
Erythemato-Exfoliative
Skin Disorders
Wojciech Francuzik, Aleksandra Skłodowska
Tutor: Prof. Zygmunt Adamski
Student Scientific Working Group of Skin Diseases

2. The difficulties of diagnosing skin
disorders
?

4. What is it? Definetly not this!

5. Materials
Database form the UCI repository was used in
this study, with retrospective diagnosis of six
diseases:
Database consisted of 366 Patients
PR
Pityriasis rosea
P
Psoriasis
LP
Lichen planus
CD
Chronic dermatitis
SD
Seborrhoeic dermatitis
PRP
Pityriasis rubra pilaris
Source: http://archive.ics.uci.edu/ml/datasets/Dermatology

6. METHOD
Clinical Attributes:
1: erythema
2: scaling
3: definite borders
4: itching
5: koebner phenomenon
6: polygonal papules
7: follicular papules
8: oral mucosal involvement
9: knee and elbow involvement
10: scalp involvement
11: family history, (0 or 1)
34: Age (linear)

7. Histopathological Attributes:
12: melanin incontinence
13: eosinophils in the infiltrate
14: PNL infiltrate
15: fibrosis of the papillary dermis
16: exocytosis
17: acanthosis
18: hyperkeratosis
19: parakeratosis
20: clubbing of the rete ridges
21: elongation of the rete ridges
22: thinning of the suprapapillary epidermis
23: spongiform pustule
24: munro microabcess
25: focal hypergranulosis
26: disappearance of the granular layer
27: vacuolisation and damage of basal layer
28: spongiosis
29: saw-tooth appearance of retes
30: follicular horn plug
31: perifollicular parakeratosis
32: inflammatory monoluclear inflitrate
33: band-like infiltrate
METHOD

8. 0, 1, 2, 3
0 & 1

9. Statistical analysis
PR
P
LP
CD
SD
PRP
All othervs & Odds
Ratio

10. Algorithm preparation
PR
P
LP
CD
SD
PRP
Distinctive features
Algorithm design
Over 95% of correct diagnosis

11. Results
P
CD
PRP
Definite borders OR= ∞ (6,856 - ∞)
Thinning of the
suprapappilary epidermis OR= 3402 (527.161-30722.447)
Elongation of the rete ridges OR= ∞ (79,848 - ∞)
follicular papules OR= ∞ (90- ∞)
follicular horn plug OR= 2172,33 (185,951- 62594.677)
follicular parakeratosis OR= ∞ (513.304- ∞)
fibrosis of the papillary dermis OR= ∞ (908.579 - ∞)

12. Results
LP
SD
PR
Polygonal papules OR= ∞ (900,336- ∞)
Melanin incontinency OR= ∞ (∞ -1158,445)
Oral mucosa involvement OR= ∞ (614,1 - ∞)
Polygonal papules OR= 0
Knee and elbow involvement OR= 0 (0- 0,1)
Follicular papules OR= 0
Polygonal papules OR= 0
Clubbing of the rete ridges OR= 0
Saw tooth apparence OR= 0

15. Imperfections
• Unability to differentiate
properly between
Pityriasis rosea and
Seborrhoeic dermatitis

16. Results
LP
SD
PR
Polygonal papules OR= ∞ (900,336- ∞)
Melanin incontinency OR= ∞ (∞ -1158,445)
Oral mucosa involvement OR= ∞ (614,1 - ∞)
Polygonal papules OR= 0
Knee and elbow involvement OR= 0 (0- 0,1)
Follicular papules OR= 0
Polygonal papules OR= 0
Clubbing of the rete ridges OR= 0
Saw tooth apparence OR= 0

17. Results
LP
SD
PR
Polygonal papules OR= ∞ (900,336- ∞)
Melanin incontinency OR= ∞ (∞ -1158,445)
Oral mucosa involvement OR= ∞ (614,1 - ∞)
Polygonal papules OR= 0
Knee and elbow involvement OR= 0 (0- 0,1)
Follicular papules OR= 0
Polygonal papules OR= 0
Clubbing of the rete ridges OR= 0
Saw tooth apparence OR= 0
+ Herald Patch !!!

18. SPECIAL THANKS TO
DATA PROVIDERS:
Professor Nilsel Ilter, M.D, PhD.
Grazi University
Professor Altalay Guvenir PhD.
Bilkent University

19. Collaboration and Open Data Sharing