Prurigo pigmentosa in a fair-skinned European woman: Dramatic improvement with doxycycline

INTRODUCTION

Prurigo pigmentosa is a rare inflammatory, pruriginous skin disease seen predominantly in young Asian women, with average age of onset in the mid-20s.

OBSERVATION

A 25-year-old fair-skinned European woman presented with a two-year history of pruriginous skin lesions recurring fortnightly. The initial lesions were inflammatory papules, which first emerged on the back of the neck before spreading to the shoulders, below the breasts and the back. The papules resolved leaving a reticular hyperpigmented network that gradually worsened after each episode. The clinical presentation and histopathological findings were consistent with a diagnosis of prurigo pigmentosa. Doxycycline 200mg/day was initiated, with rapid resolution, absence of any further flare-ups and gradual regression of the reticular pigmentation.

DISCUSSION

Prurigo pigmentosa is a skin disease of stereotypical presentation marked by frequent inflammatory flare-ups involving the trunk that are followed by periods of remission with residual hyperpigmentation. Herein we report a case observed in a fair-skinned French female subject. It is important that dermatologists are able to recognize it and distinguish it from other forms of pruriginous papular dermatosis, owing to the dramatic efficacy of tetracyclines in controlling the inflammatory flares and in reducing the adverse aesthetic impact of hyperpigmentation.

[Hookworm-related folliculitis in a woman performing skin bleaching in Benin]

Hookworm-related cutaneous larva migrans is caused by the subcutaneous migration of hookworm larvae. The characteristic sign is a serpiginous cutaneous track. Folliculitis is an uncommon clinical manifestation. We report a case of hookworm-related folliculitis in a woman performing skin bleaching. A 33-year-old woman presented with a widespread cutaneous eruption made of erythematous and itchy follicular papulo-nodules, with erythematous serpiginous tracks, about 5-10cm long and numerous streaks of scratching, located on the limbs, buttocks and trunk. The cutaneous lesions occurred two days after contact with the floor of a warehouse contamined by faeces of cats. The lesions have been evolving for a week and have been treated with antibiotics without success. Clinical examination found cutaneous atrophy, purple stretch marks and hyperpigmentation of dorsal parts of fingers joints. The patient reported having been using bleaching cosmetics containing topical steroids and hydroquinone for twelve years. She was cured within 4 weeks with oral albendazole 400mg per day during 7 consecutive days.

Taxonomy and phylogeny of Cutibacterium (formerly Propionibacterium) acnes in inflammatory skin diseases

Since its discovery, Propionibacterium acnes has undergone various name changes, and has been known since 2016, as Cutibacterium acnes. Herein we set out the history and rational of these taxonomic changes together with a description of a new genus, Cutibacterium, which includes five species within the cutaneous ecosystem. Modern microbiological techniques allow finer distinction between species and subspecies while also enabling the identification of separate subtypes within the population of Cutibacterium acnes. Phylogeny and molecular typing techniques thus provide a better understanding of the subtypes involved in certain inflammatory skin diseases, including acne, folliculitis and progressive macular hypomelanosis.

Disseminate recurrent folliculitis as the presenting picture of hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) has a polymorphous clinical presentation. Herein we report two cases of HS revealed by disseminate recurrent folliculitis. PATIENTS AND METHODS CASE 1: A 31-year-old woman consulted for disseminate recurrent folliculitis on the trunk and proximal segments of the limbs that had been ongoing for several years. No other cutaneous lesions were seen, particularly in the classic area for HS lesions. Weight loss and treatment with azithromycin 500mg/day resulted in complete remission, but relapse occurred on dosage reduction. CASE 2: The elder sister of patient 1, who was also obese and 10 years her senior, presented a similar clinical history, although in addition, she was presenting lesions characteristic of HS on her armpits and inguinal folds; further, she had undergone an operation 3 years earlier for pilonidal sinus. Three months of combined treatment with rifampicin and clindamycin 900 mg/day followed by long-term doxycycline 200mg/day resulted in marked improvement.

DISCUSSION

Disseminate folliculitis is not infrequent during the course of HS; it forms part of the clinical picture and is particularly common in the follicular phenotypic variant; however, it is not part of the diagnostic criteria as defined consensually by the Hidradenitis Suppurativa Foundation. The cases we report suggest that a setting of disseminate recurrent folliculitis may constitute the mode of presentation of HS, and may even represent an atypical monosymptomatic form of HS.

CONCLUSION

Disseminate recurrent folliculitis constitutes part of the clinical picture of HS; if it is isolated, screening should be performed for personal or familial signs of HS.

[Pseudomonas aeruginosa in dermatology]

Pseudomonas aeruginosa, a ubiquitous Gram-negative bacillus characterized by its greenish color and sweetish smell, is at the origin of potentially severe forms of dermatosis, such as ecthyma gangrenosum which marks immunosuppression or reveals blood-poisoning, especially in children. It frequently colonizes chronic wounds and serious burns, and spongiotic or acantholytic dermatosis, especially when severe or localized in skinfolds. It requires special care because of its high resistance to antibiotics and antiseptics. It can also involve folliculitis favored by water sports or a nail disorder (chloronychia).

[Cutaneous lesions during hot-tub hypersensitivity pneumonitis: Pseudomonas folliculitis ?]

BACKGROUND

Interstitial lung disease, cutaneous rash and elevated serum angiotensin converting enzyme (ACE) may suggest diagnoses other than sarcoidosis.

PATIENTS AND METHODS

A 58-year-old man had presented dyspnoea for 2 years with increased angiotensin-converting enzyme, as well as an interstitial syndrome and micronodules. The possibility of sarcoidosis was raised. Systemic corticosteroids resulted in improvement of the dyspnoea although it recurred on dose reduction. We noted fluctuating eczematous macules of the limbs with a histology of aspecific folliculitis. The identification of Mycobacterium avium complex (MAC) in the bronchoalveolar wash prompted us to initiate antimycobacterial therapy, but this was to no avail. Review of the CT-scan and questioning of the patient (daily use of a Jacuzzi for 7 years) resulted in diagnosis of hypersensitivity pneumonitis due to MAC. The cutaneous lesions were taken to indicate "hot tub folliculitis". Discontinuation of hot-tub use and a short course of oral corticosteroids resulted in healing within 4 months, with no recurrence at 2 years.

DISCUSSION

HTL is a form of hypersensitivity pneumonitis due to the presence of MAC in the water of Jacuzzis. This condition regresses spontaneously without treatment on discontinuation of Jacuzzi use. Hot-tub folliculitis due to Pseudomonas aeruginosa (PA) presents as macules and papules on covered skin areas (swimsuit) within 48hours of bathing and often declines within 2 weeks.

CONCLUSION

Our case is original as regards the concomitant lung and cutaneous involvement associated with Jacuzzi use, with an immunoallergic mechanism for the MAC and probably an infectious mechanism for the PA.