The causes of blepharitis
The most common cause is infectious (Staphylococcus). Anterior blepharitis, reaching the skin of the eyelid and/or eyelashes can be of allergic origin, with red patches of rash. The allergy is due to products that have been applied to the eyelid (makeup, creams...) or present in the air (pollens...), and the eye is often also affected. If allergy is suspected, please consult an allergist to determine what the substances responsible are, which can then be avoided.
Certain diseases of the skin such as psoriasis or eczema can affect the skin of the eyelids.
It can also be due to an infection (herpes, shingles, Golden staph, demodex...). In this case, there may also be a skin rash on the eyelid.
Posterior blepharitis may be inflammatory, as part of broader immune diseases such as Gougerot-Sjögren syndrome (a disease with multiple manifestations, including joint problems and dry eye) or affecting the skin across the body. But it is most often due to a dysfunction of Meibomian glands . These tiny glands present on the edge of the eyelids are responsible for producing lipids (fat) that form the "meibum" and mix with tears to lubricate the surface of the eye.
Sometimes they become inflamed:
• When the meibum is too thick and clogs the hole of the gland, which then appears as a small white dot.
• With certain illnesses, affecting both the face and eyelids, such as rosacea, seborrheic dermatitis... These diseases are characterized by inflammation and excessive production of sebum in the skin and meibum in the eyelids. Pustules (spots) can be seen on the face or scalp and on the edge of the eyelids.