Can scalp cysts cause hair loss?

Scalp cysts refer to growths that form under the skin of the head. They typically appear as small rounded bumps and can vary in size, ranging from a few millimetres to several centimetres in diameter. Often painless, these cysts are most commonly discovered by chance, during hair brushing, a visit to the hairdresser, or during a medical examination. Although most scalp cysts are benign, some can cause aesthetic discomfort, local sensitivity, or even pain if they become infected. That's why it is advisable to consult a healthcare professional if in doubt about a scalp cyst. This also helps to rule out the risks of basal cell carcinoma, a type of scalp cancer.

Generally, scalp cysts do not lead to hair loss.

However, in rare instances, certain cysts have been linked to localised alopecia. Indeed, in 2012, a scientist reported 11 cases of pseudocysts on the scalp associated with hair loss around the growth. Pseudocysts are flesh-coloured rounded masses whose etiology is unknown, although a follicular occlusion, similar to that occurring in the case of sebaceous cysts, is suspected. After two consecutive monthly treatments with intralesional triamcinolone acetonide (2.5 mg/mL), the pseudocysts completely disappeared and the hair regrew normally. In the case of pseudocysts, hair loss therefore seems possible. However, it is worth noting that these growths are quite rare.

Another rare case of cysts associated with hair loss: Alopecic and Aseptic Nodules of the Scalp (AANS). This is an underdiagnosed condition that presents with one or more inflammatory nodules on the scalp accompanied by non-scarring alopecia above. The nodules can be soft, fluctuating or firm. Although the etiology of AANS is not clearly identified, a process of follicular obstruction or deep folliculitis has been theorised. AANS are generally treated with oral antibiotics, such as doxycycline, intralesional corticosteroids or with excision. Once the nodules are removed, hair usually regrows normally.

Note : The two conditions mentioned above are rare. In most cases, scalp cysts correspond to sebaceous cysts or lipomas and do not cause alopecia.