Trichoscopy: The new method for the diagnosis of hair disorders.
Trichoscopy is hair and scalp dermoscopy with the use of a hand-held dermoscope or polarized light video microscope.
The following should be observed carefully: loss of orifices, micropustules and/or hair tufting with six or more hairs. In cases that it is not possible to observe the loss of hair orifices in the hair loss area, diagnosis as noncicatricial alopecia is established.
In the category of noncicatricial alopecias, alopecia areata is most commonly encountered and should be mainly considered for differential diagnosis. In this case, the first points to be checked include yellow dots, black dots and/or broken hairs.
The most characteristic feature of androgenetic alopecia and tinea capitis is the diversity of hair diameter (>20%) and comma hairs, respectively.
At first, dermoscopy was used for the observation and diagnosis of pigmented skin lesions, such as melanocytic nevus and melanoma, while for the diagnosis of hair diseases it was suggested that dermoscopy, especially when no immersion gel was used, is a different method for hair diseases as compared to classical dermoscopy. This method was called trichoscopy at a later stage.
Given the fact that trichoscopy is a non-invasive method that facilitates access to hair and scalp, it is a really useful tool in clinical practice.
Through trichoscopy it is possible to examine and make the diagnosis of hair disorders such as alopecia and disorders of the hair shaft without skin biopsy, which would be essential in any other case to make a diagnosis.
In conclusion, trichoscopy is a really powerful tool for the diagnosis of hair loss disorders. Nevertheless, final diagnosis should be conducted based on the assessment of both trichoscopic and clinical images. In cases of unresolved contradictions, repetitive examination and histopathological investigation are recommended. Furthermore, the algorithm for hair loss concerns only a limited number of hair loss disorders and therefore expansion to a wider range of conditions is required.
Classification of Alopecias
- Normal alopecias
- Alopecia areata
- Androgenetic alopecia
- Alopecia due to the effects of other harmful factors
- Diffuse alopecias depending on the phototrichogram’s images
- Telogen effluvium
- Anagen effluvium
- Mixed alopecia
- Diffuse alopecias depending on the harmful agent/factor
- Diffuse alopecia in endocrine disorders
- Diffuse alopecia due to medications and chemical compounds
- Diffuse alopecia due to nutritional and metabolic disorders
- Chronic diffuse alopecia
- Traumatic Alopecias
- Traction alopecias
- Cicatricial alopecia
CAUSES & PATHOGENESIS
- Genetic factors
- Psychological factors
- Immunological factors
- Endocrinological factors
- Other factors
- Syphilitic alopecia
- Post-inflammatory and cicatricial alopecias
- Topical treatments
- Irritants (Anthralin 2-3%)
- Topically applied minoxidil
- Topically applied allergens (DNCB Diphencyprone)
- Systemic therapies
- Zinc sulphate
CAUSES OF DIFFUSE ALOPECIA
- Fe deficiency
- Endocrine causes (hypothyroidism – Addison disease)
- After pregnancy and discontinuance of contraceptives
- Rapid weight loss
- Anorexia nervosa
- Protein – caloric malnutrition
- Lack of essential fatty acids
- Anagen alopecia
- Cytostatics, X-rays
- Telogen alopecia
- Antithyroid medication
- Boric acid
- Cholesterol lowering medication
- Hypervitaminosis A
- Trauma (chemical – physical)
- Undiagnosed causes
- Developmental disorder and hereditary conditions: skin aplasia, epidermal nevi, porokeratosis of Mibelli, ichthyosis, Darier disease, etc.
- Defects due to natural causes: mechanical traumas, burns, x-ray dermatitis.
- Microbial infections: tinea/ringworm infections, bacterial infections (lupus vulgaris, leprosy, syphilis tritogonos, furuncle, psefdanthrax, folliculitis, acne necrotising), leishmaniasis, viral infections (herpes zoster, chickenpox, smallpox).
- Neoplasias: basal cell carcinoma, cicatricial (scarring) basal cell carcinoma, metastatic carcinomas.
- Various other dermatoses/skin diseases of unknown aetiology: lichen planus, lupus erythematosus, scleroderma, lipoid necrobiosis, sarcoidosis, benign mucous membrane pemphigoid, follicular mucinosis, etc..
- The conversion of circulating testosterone in 5a-dihydrotestosterone in sensitive follicles mediated by the enzyme 5a-reductase
- Increase of 5a-dihydrotestosterone concentration at the sensitive hair follicles leads to the inhibition of the metabolism of these hair follicles
While androgens are responsible for androgenetic alopecia in men, their action is stimulating for all other follicles of the body (beard, underarms, genital area, body).
- Before the age of 20 years old in 5% of men
- Symmetrical fronto-temporal hair thinning
- Mild hair loss along the front line (type Ι)
- During the 3rd decade it can be combined with partial hair loss at the top of the head (type ΙΙ)
- Its onset is at a later age and its progress slower
- Type Ι :25% of women at the age of 40 years old
- Auto-micro-transplantation of single follicular units