Acne keloidalis nuchae (AKN) involves inflammation at the back of the scalp. It can cause an itchy rash, swollen, painful hair follicles, and sometimes pus-filled bumps.

Scarring can occur also occur as a result of AKN, and the scars may be stiff and raised. Some people may also experience hair loss in the area.

Keep reading to learn more about AKN, including the causes and symptoms, and how to treat it.

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Photography by DermNet New Zealand

Despite its name, “acne keloidalis nuchae” is not a type of acne. Other names for it, some of which are also misleading, include follicular keloidalis, acne keloidalis, and acne cheloidalis nuchae.

This condition causes inflammation and swollen, painful hair follicles at the back of the scalp. Pus-filled lesions may follow, and without treatment, these lesions can form scars.

AKN is much more common in males than females, at a ratio of 20 to 1, according to a 2016 review. It also seems to affect people with darker skin more frequently than people with lighter skin, possibly due to hair type.

Overall, the incidence rate is 0.45% to 9.0%, the same review reports.

AKN usually begins after adolescence. While the exact cause is not clear, the following factors may play a role:

  • Irritation: Tight headgear or shirt collars can cause friction and irritation that may contribute.
  • Hair-cutting: Close shaves and trims can injure the skin or lead to ingrown hairs.
  • Heat or humidity: These conditions can increase inflammation.
  • Male hormones: Since AKN occurs mostly in males, specific sex hormones are likely involved.
  • Genetics: People with coarse or curly hair develop AKN more often than people with other hair types.
  • Infection: This might result from contaminated barber tools.
  • Other skin conditions: People with seborrhea may also develop AKN.
  • Autoinflammation: Molecular structures called antigens in the hair follicle can trigger inflammation.
  • Medications: The immunosuppressant medication cyclosporin and the epilepsy drugs carbamazepine and phenytoin may cause AKN.

The first symptom of AKN is usually an itchy rash around the hair pores at the back of the scalp. It can be tempting to scratch, pick at, or rub the area, but this can cause further irritation.

The rash may turn into papules and pustules. Once these heal, they may leave scars.

A doctor diagnoses the issue by examining the look and feel of the skin. They also ask about hair care routines and other factors that could be causing AKN.

The doctor may also test for an infection, as the result can help guide treatment.

The right approach to AKN depends on the cause and severity of the symptoms. Treatment may begin with over-the-counter products. Skin cleansers that contain benzoyl peroxide or chlorhexidine may help get rid of a bacterial infection, and tar shampoos may also be helpful.

People often need stronger products as the condition progresses. Receiving professional care while the inflammation is still mild may help prevent more severe lesions that lead to scarring.

A family doctor or dermatologist can recommend the best medication for each case of AKN, and it is important to use this exactly as prescribed. Dealing with AKN may involve using the medication for several months.

Sometimes, a person needs to use more than one type of treatment at the same time. The goals are to keep the condition from spreading and prevent scarring.

Treatment options include:

  • Antibiotics: If a bacterial infection is responsible, a doctor can prescribe topical or oral antibiotics, such as cefadroxil, clindamycin, doxycycline, erythromycin, and minocycline.
  • Corticosteroids: These oral, topical, or injected drugs reduce inflammation. Examples include betamethasone, clobetasol, fluocinolone, mometasone, and triamcinolone.
  • Retinoids: These topical or oral products also reduce inflammation. Examples include isotretinoin, acitretin, and tretinoin. They work by increasing cell turnover and keeping the pore unclogged.
  • Laser and light therapy: These treatments destroy hair follicles and can improve the appearance of lesions. People may need several sessions to treat AKN.
  • Surgery: Doctors only suggest this when all of the other options have not worked.

Recent research has focused on the use of lasers for AKN treatment. One small study suggests that six sessions of alexandrite laser treatment could shrink the lesions and improve the quality of life. Another study reports decreases in lesion size following laser therapy. Confirming these findings will require further research with more participants.

The following preventive methods may be effective:

  • avoiding close shaves and trims, particularly at the barber’s, where tools may not be cleaned thoroughly enough to prevent infection
  • keeping the area clean and dry, also to prevent infection
  • not wearing tight collars and headgear, to prevent irritation
  • avoiding greasy hair products

AKN causes inflammation at the back of the scalp, and it can lead to an itchy rash, pus-filled bumps, scars, and possibly hair loss.

This health issue is more common in males and people with darker skin. A person can take some steps to prevent it.

Various medications and other therapies can treat AKN and help prevent permanent scarring.