A presentation was devoted to common scalp pathologies during Paris Dermatology Days (JDP 2024) . After exploring the squamous pathologies, the Dr Philippe Assouly (dermatologist at the Sabouraud center, Saint-Louis Hospital, Paris) set out to describe the diseases that can lead to hair loss, such as effluvium and alopecia, by distinguishing between scarring and non-scarring forms. [1].
Diagnostic clinique
“When we talk about hair loss, we distinguish between alopecia and effluvium,” explained the dermatologist in the preamble. Alopecia covers a decrease in hair density, with or without excessive hair loss, while effluvium is excessive hair loss, with or without a decrease in hair density.
Faced with hair loss – neither more nor less than a symptom – the first step is to establish the cause, “knowing that the severity is not proportional to the extent of the loss”, clarified the dermatologist.
Acute telogen effluvium
Acute telogen effluvium is one of the most common causes of consultation for scalp pathologies, much more so in women. This is a diffuse hair loss with a rather sudden onset, all the more visible as it occurs preferentially in the parieto-temporal areas, where the hair density is, initially, lower. The first cause is the season, in this case autumn due to the growth of telogen hair in summer, and its loss two months later. “There is no point in taking tablets or giving injections, it is of no use, it is a seasonal physiological phenomenon,” assured the speaker. You should also look for a high fever (> 39°C for 3 days), following flu, Covid-19, dengue fever, which can cause significant hair loss, which will subsequently grow back. Weight loss (diet), significant diarrhea, a procedure with prolonged anesthesia, syphilis, physical stress or the start of treatment with minoxidil can be responsible for acute but transient telogen effluvium.
Chronic telogen effluvium
Among the causes of chronic telogen effluvium (> 6 months), always think of endocrine diseases, primarily the thyroid and hypothyroidism, points out Dr. Assouly. Also worth mentioning: severe, poorly balanced chronic pathologies (hepatic, renal, pancreatic, etc.), advanced cancer or lymphoma, lupus, deficiencies (iron, vitamins, zinc, etc.). Depression or an anxiety-depressive state can contribute to effluvium, as can an inflammatory dermatosis (acute eczema of the scalp, psoriasis, burns, etc.).
To establish the diagnosis, we carry out a traction test, in short, “we pull and look at the amount of hair that falls out”. To find the cause, if people are well, the biological assessment to be carried out is very limited: CBC, ferritin or serum iron, TSH, B12. “We adapt according to the calling signs. And if there is no cause, we reassure and there is no need to give treatment,” considers the specialist.
What treatment?
Effluvium is either related to a known cause or called chronic idiopathic telogen effluvium. In the latter case, it is more the prerogative of women around menopause, with a hair cycle which becomes irregular which generates this idiopathic effluvium.
How to treat telogen effluvium? “Either there is a cause, and we treat it, or we do nothing. However, if this hair loss generates significant stress, minoxidil can be prescribed, warning that the hair will fall out en masse in the first weeks, before it begins to grow back. It is possible to give a placebo (sulphur-containing amino acids, vitamins, etc.), knowing that there are exorbitantly expensive treatments such as PRP (platelet-rich plasma) injections, light therapy and mesotherapy, which have not been proven of their effectiveness,” advises the dermatologist.
Effluvium anagène
The case of anagen effluvium is very particular, it is a sudden hair loss, either under the effect of chemotherapy or under the effect of a toxic agent. The toxic process can be of chemical origin: thallium, mercury, arsenic, copper, cadmium, bismuth or of plant origin: colchic cytostatics, cantharidin, cashew nuts, cucurbits. Another cause of sudden hair loss: radiotherapy, which blocks mitoses, with the consequence of a permanent loss beyond 45 Gy, and regrowth after 2 to 4 weeks otherwise.
Non-scarring alopecia
Alopecia, for its part, can be of two types: scarring or non-scarring. Female androgenic alopecia is an example of non-scarring alopecia, with the main sign being a thinning of the hair on the top of the head (known as a Christmas tree shape). We speak of anisotrichia in dermoscopy, with more than 20% of hair having a reduced caliber. Female androgenic alopecia is very common, with a variable age of onset. “The whole question is to know if we are in the presence of hyperandrogenism (acne, seborrhea, hair growth, cycle disorders). In the absence of hyperandrogenism, there is nothing to do. On the other hand, the presence of hyperandrogenism will lead to a hormonal assessment being carried out, then possibly to seeking the advice of an endocrinologist. If the onset is very sudden, and is accompanied, a fortiori, by a very male distribution with a decline in the fronto-temporal gulfs, then we must look for a tumor cause, for example, ovarian,” considers Dr. Assouly.
Treatment consists of adapting contraception if necessary, treating hyperandrogenism if necessary, and giving minoxidil. “The AMM recommends 2%, but we most often give 5% in small quantities. We monitor hyperpilosity and adjust the dose accordingly, because it will have to be taken over the long term,” specifies the dermatologist.
Example of male androgenic alopecia, Credit: dreamstime
Among men, we talk male androgenic alopecia – again an excessively physiological phenomenon – which results in a retreat of the temporo-frontal gulfs with a different pattern depending on ethnic origins and a thinning of the hair on the top of the skull. Around a hundred genes are involved in this fall but family history constitutes an additional risk. Treatment involves minoxidil 5% applied locally (or oral minoxidil but off-label), the other option being finasteride 1 mg/day, with provision of a document from the ANSM to warn of the adverse effects of this product. These treatments must be taken for life. “Remember to take photographs because patients always have the impression that the phenomenon is getting worse,” advises Dr. Assouly. If you decide not to treat yourself, sun protection – cream or hat – is essential. Hair transplants are also an option.
Another type of non-scarring alopecia, scaly, this time: ringworm. It is found mainly in children but also in postmenopausal women. It results in short, broken hair but above all in scales/crusts/pustules. Any alopecia of this type should suggest ringworm and, if there is the slightest doubt, a mycological sample should be requested. Dermatoscopy can nevertheless direct towards the type of fungi. Treatment consists of terbinafine if trichophytic suspicion, itraconazole if microsporic suspicion. It is important to cut the hair around the area and apply local treatment with topical antimycotics. “Remember to treat those around you and the pet if necessary” adds the speaker.
Alopecia areata is the leading cause of non-scarring patchy alopecia. It is an autoimmune disease that can occur at any age. Lymphocytic inflammation of the hair follicle bulb causes hair loss and possibly creates changes to the nails. “It is not a psychological illness, even if it sometimes occurs after an event” indicates the dermatologist.
Example of alopecia areata, Credit: dreamstime
There are two important clinical signs: exclamation point hair and relative white hair. No systematic assessment to prescribe, but look for another autoimmune disease, particularly thyroid. The treatments for alopecia areata are topical corticosteroids (class 4 lotion), injections of depot corticosteroids diluted into the dermis, from the age of 13, systemic corticosteroid therapy in certain cases, janus kinase inhibitors with baricitinib (reimbursed for a few months). ), ritlecitinib (since a few days in pharmacies), contact immunotherapy (diphencyprone), phototherapy (PUVA) in certain cases, and methotrexate (off-label) – “discussed and debatable”. Do not hesitate to contact patient associations, who will help you do the best you can, advises the dermatologist. Hair prostheses reimbursed at 60% by social security are also an option.
THE traumatic alopecia are another possible cause of hair loss: brutal traction (household accident), traumatic traction alopecia (due to excessive tension of the hair when wearing a bun or very tight braids on afro hair), alopecia by pressure (post intervention or coma), chemical trauma (with straightening products) or alopecia resulting from self-inflicted dermatosis (by trichotillomania, trichoteiromania or trichtemnomania).
Faced with non-scarring alopecia, we must, finally, know how to mention syphillis, which causes clearing alopecia and also affects the eyebrows.
Cicatricial alopecia
The diagnosis of scarring alopecia, that is to say a smooth scalp without hair openings, requires a whole protocol which will possibly involve biopsies. Among the main causes, we find lichen planus pilaris which results in small centrifugal and coalescing plaques, accompanied by erythema and perifollicular hyperkeratosis. There are two forms: the classic plaque form and frontal fibrosing alopecia. The latter affects 97% of women and is characterized by a progressive retreat of the implantation line and damage to eyebrow hair.
Other non-scarring alopecia pathologies to be aware of are discoid lupus erythematosus (which preferentially affects black skin), décalvante folliculite, dissecting cellulite of the scalp or even occipital fibrosing folliculitis.
