Folliculitis decalvans: Hair loss on scalp

Folliculitis decalvans is a rare chronic condition. Inflammation of the hair follicles causes painful, scarring hair loss (alopecia) on the scalp. This condition with unknown cause is associated with a certain type of bacteria. The doctor therefore also uses antibiotics to treat the disease. However, treatment is difficult and therefore other medications and therapies are available to slow down scarring hair loss. The bald spots on the scalp are permanent and hair regrowth is no longer possible. Finally, the disease has a chronic and variable course.

  • Epidemiology of folliculitis decalvans
  • Causes
  • Symptoms: Scarring hair loss on scalp
  • Diagnosis and examinations
  • Treatment of round or oval spots
  • Prognosis of chronic hair condition
  • Complications of hair loss


Epidemiology of folliculitis decalvans

This is a common primary form of alopecia (hair loss) with an incidence of 1.9-11.2% in patients suffering from a form of scarring alopecia. Men usually suffer from the hair condition from adolescence onwards, while women usually do not develop the disease until the fourth decade.


The cause of the non-infectious condition is not known as of October 2020, but the pathologist sometimes cultures Staphylococcus aureus (staphylococcal bacteria) from the skin lesions. Scientists suspect that patients with the disease react abnormally to the bacteria. The inflammatory disease may also be a form of an autoimmune disease in which the immune system attacks its own cells, causing inflammation of the hair follicles. Folliculitis is not usually hereditary, although there are rare reports in the medical literature of the hair condition affecting members of the same family.

Symptoms: Scarring hair loss on scalp

The scalp is usually affected by the chronic inflammation. Very rarely, other hair-bearing areas of the skin are affected, such as the arms, legs, chest, pubic area and/or face (more common in men).In folliculitis decalvans, the infected scalp shows papulopustular (bumps and pimples) that often coalesce. This is accompanied by an itchy and painful scalp. Redness, swelling and crusting then develop on the affected part of the scalp. Afterwards, pus-filled patches develop on the back of the head and crown, but any other part of the scalp may be affected. Ultimately, purulent, scarring hair loss occurs (cicatricial alopecia). This is manifested by one or more round, oval or irregular bald spots that slowly enlarge. A frequent clinical finding is ‘tufting folliculitis’. The patient loses clumps of five to fifteen hairs that come together from the scalp.

Diagnosis and examinations

Diagnostic research

The doctor usually diagnoses folliculitis on the scalp based on its appearance. The doctor sometimes takes a swab from an affected area on the scalp and then has it examined in the laboratory for the presence of a bacterial infection. Often (but not always) the pathologist finds the bacterium Staphylococcus aureus . Because a fungal infection (ringworm) sometimes resembles folliculitis decalvans, the laboratory also tests skin scrapings or plucked hairs for the presence of a fungus. Sometimes the doctor takes a small skin sample (biopsy) and has it checked under a microscope to confirm the diagnosis. The doctor must locally anesthetize the scalp via an injection. He then has to apply stitches to close the wound, which leads to a small scar.

Differential diagnosis

Some other conditions with a similar appearance to decalvans folliculitis include:

  • acne keloidalis
  • acne necrotica
  • bacterial folliculitis
  • central centrifugal cicatricial alopecia
  • chronic discoid lupus erythematosus (CDLE)
  • cicatricial alopecia nno
  • dissecting cellulite from the scalp
  • dissecting folliculitis (perifolliculitis capitis abscedens et suffodiens)
  • hidradenitis suppurativa (chronic skin disease)
  • kerion
  • lichen planopilaris (hair loss of the scalp)
  • pseudopelade of Brocq
  • seborrheic dermatitis (skin disease with dandruff and red skin)


Treatment of round or oval spots

This chronic inflammatory disease is a challenge for the doctor to treat. Folliculitis decalvans sometimes responds to oral (taken by mouth) antibiotics, but usually returns after interruption of treatment. The doctor also uses systemic photodynamic therapy, which produces positive results in a number of patients. Other possible treatments include isotretinoin (Myorisan, Claravis), a prescription form of vitamin A, and oral corticosteroids to reduce inflammation and its spread.

Prognosis of chronic hair condition

Folliculitis decalvans usually has a long course of variable severity. The disease is usually progressive, but the symptoms often disappear spontaneously at a certain point. However, flare-ups are possible. The hair loss is permanent because the hair follicles are destroyed. Because the patient suffers from permanent hair loss, this has a negative impact on the quality of life.

Complications of hair loss

Severe scarring sometimes occurs. The development of squamous cell carcinoma, a form of skin cancer, is another rare complication.

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